Overextended clam?

[LCDRDATA]

We bought a croseus clam for our 75 gallon setup at the end of August. We knew it had to be fairly high up in the tank to get enough light. It didn't seem happy the first 2-3 places we put it - we kept getting up in the morning to find it "face down" on the bottom of the tank after it had let go and fallen off of where we'd placed it. It's been where it is now for a couple of months, though, so I think we've solved that problem.

However, we noticed early on that the mantle was extended much farther out than we'd expected. :confused: It's something like 3-4 inches beyond the edge of the shell:

http://reefcentral.com/gallery/data/500/194807hypermantle_1.jpg
http://reefcentral.com/gallery/data/500/194807hypermantle_2.jpg

Is this normal, and if not, why might it be doing this? We're feeding it regularly with DT's phytoplankton, and water parameters are good (we've just been through a nitrate spike, but that seems to be over, and there was never any difference in this regard before, during, or now after). Any insights are greatly appreciated!

[tmcgaughey]

great question.. i'm along for the ride

[Reef Newb11]

What lighting do you currently have? it could be that the clam is reaching for more light. You could try placing a small flat rock underneath the clam and get it to attach to that then you should be able to move it higher up and hopefully he wont keep jumping off.

[LCDRDATA]

The current lighting is two twin 48" T5s - one has two 10,000K (I believe) bulbs, the other has one 10,000K and one actinic. The 10,000Ks might all be 14,000Ks, but it's definitely one or the other.

We thought about trying to place it higher, but it's within 5" of the surface as is, and there didn't seem to be anyplace more than about an inch closer to the surface - the one place that was higher was the second location we tried, only to find it face down in the sand the next morning.

If it ever lets go of its current location (it has shifted an inch or two since being placed) we'll try to get it anchored to something we can then move, but I'm very hesitant to try to pry it off of the rock it's currently anchored to.

Here are a couple more pics; although they're not the greatest quality I think you can see what I'm asking about:

http://reefcentral.com/gallery/data/500/194807hypermantle_3.jpg
http://reefcentral.com/gallery/data/500/194807hypermantle_4.jpg

But I understand that it may be looking for more light. Are there any other possibilities?

[Lenny718]

In all my years in the hobby I never saw a clam extend so much, I will also be tagging along to find out.

[E.intheC]

I'm along for the ride as well.. hopefully the clam will be okay!

[tmcgaughey]

sounds like you need a bunch more lighting
that doesn't sound like much for a clam at the bottom of your tank

[jedheuer]

Hi,

Not an expert here but I have had a similar experience. I would guess that you you have too little light for the clam and it is hyper extending in order to compensate for the lack of light.

I have a clam that looks almost exactly like yours. I run 36" 8x 39w T5 HO 10,000 K bulbs over my 40g tank. The clam sits on a rock on the sand 16" below the lights. I placed a peice of eggcrate over the tank to keep some clown fish from jumping out and that reduced my light somewhat. The clam started hyper extending exactly like yours and now is bleaching around the edges of his mantle. I removed the eggcrate and will change the bulbs if the clam doesn't recover soon.

Based on my experience with 8 x 36" t5's, I would think that you need much more light than 4 t5s over your 75 for your clam.

Best of luck, you've got a nice clam there!

[LCDRDATA]

So far it looks like three votes for more light - any other ideas? Do you think it's just light, or light and some other factor? In the meantime, as a stop-gap I have a 26W 6500K compact fluorescent in a plant light spot fixture and I'm putting it directly over the clam - we'll see if that helps while working on a more permanent solution.

Given the way our tank is set up, the most straightforward options to boost light would be either what I've just described, some kind of more powerful/focused spot lighting, or an additional twin 48" T5 fixture. If I go with another twin T5, those come standard with one 10,000K and one actinic - would that be enough or should I swap out the actinic for another 10,000K bulb? On either my current setup or adding a third twin, would it make any difference if I went to 14,000K or 20,000K bulbs vice the 10,000K? Metal halides aren't an option, as they literally give my wife migraines - just something about the light quality.

In terms of potentially moving the clam closer to the top of the tank - not easy as we'd need some serious rearranging, but better that than losing the clam - how can I get the clam to let go of where it's finally anchored without just ripping it off? To reverse the phrase, I don't want to add injury to insult.

The clam and I are waiting for even more of your good inputs - Thanks!

[phish guy]

do not by any means, rip the clam off. that will most likely kill it. i have heard that cutting the byssal threads with a brand new razor blade will work, but check out the clam forum first.

your clam is definitly reaching for more light. i would definitly say get more light. 4 T5s on a 75 is not enough. at least double your light. try mixing up the bulbs too. go to the equipment forum and see others configurations for their T5s, there are alot, lots more than just 10000ks and atinics.

[jmadison]

I agree more light, way more light.
Get a mixture of spectrums too, ask grimmreeper in the t5 forums
You can cut him free with a scalple or razor, just try to cut as close to the rock as possible.
Are you target feeding with phyto or just adding to the tank?
What are your params? Temps? Light schedule?

[jedheuer]

Defiantly stick with 10000 K bulbs, dont go higher or add more actinics. Clams need high PAR output which roughly speaking starts to go down as you go to a higher kelvin. Actinics also have little PAR. if you like a blue look that your actinics provide you can get 10000 plus blue, which actually put out a high PAR wave but it is visibly bluer.

It is a good idea to get your clam to attach to a small rock incase you need to move it. Maybe you can do this in the future.

[crvz]

I'd also recommend more light. Also, not sure if it was asked, but do you have individual reflectors on the T5 bulbs? That may help as well.

[khanb31]

well, if there was any clam to pick to put under that amount of lighting.....that was the wrong one. :( Based off of what you said and the looks of the shell type, youve got a crocea clam. Those croceas (along with the maximas) need the highest intensity of light of all the clams we see in the trade. And from my experiences with clams, (have 3 thus far including a crocea), you have no where near the minimum light requirements for that clam.

On a 75 gallon tank, I would recommend a minimum 2x 150W HQI (double ended) metal halide fixture. But, since your wife is bothered by them, That is out of the option which is ok.

My own personal opinion would be to try doubling or tripling of the higher intensity bulbs. I dont know anything about t5's or VHO's but you gotta get more light on that guy. How about some nice individual reflectors for each bulb? That is a very simple way to increase the light concentration/increase of PAR.

Otherwise, if you cant significantly increase the amount of light over that guy, I would suggest selling him to a local reefer who can or trade it out for a lower light clam. Something like a derasa or squamosa.

As for the removing him from the rock. You must be VERY careful about how you move him. When they attach themselves firmly to a rock, the abysal gland makes attachment strings that goes straight up into their innards and any sharp movement could cause irreparable damage. Try to slowly tilt him left, right, back and forward to see if you can spot where the attachment string is. If your wife is able to help you, have her try and shine a flashlight so you can see better.

When you first start to move the clam, its going to feel you tugging on its gland and will retract everything it can into its shell. After this has happened, you will be able to see a small strand that looks like thinned out floss. You want to cut that strand with a razor blade or a modeling knife/scalpel (preferably - you can keep your dexterity with a scalpel) and then place the clam on something like a frag plug. Here is my crocea and here are the best pictures I could get of the strands.

Put him on a frag plug like this.
http://img.photobucket.com/albums/v180/khanb31/IMG_0455.jpg

With strands outlined.
http://img.photobucket.com/albums/v180/khanb31/croceaclam.jpg

Without outlines.
http://img.photobucket.com/albums/v180/khanb31/croceaclam1.jpg

Again, with the strands outlined.
http://img.photobucket.com/albums/v180/khanb31/croceaclam2.jpg

Again without the strands outlined.
http://img.photobucket.com/albums/v180/khanb31/croceaclam3.jpg


As you can see there are multiple strands that have attached to the frag plug. Thankfully because of the shape of the plug, the clam can only attach himself to a horizontal base. This makes it easy for me to remove him if I need too. Just because the clam is able to attach himself to something doesnt mean it will keep the clam in place. The strands actually attached to individual pieces of sand in addition to the frag plug....... so it just goes to show you how versatile the strand attachment can be. Im going to put this in the clam forums.....hopefully it will get a sticky. Everyone always wants to know what these things look like.

Any more questions?

[khanb31]

I made a post about this in the clam forums. Check it out!

http://reefcentral.com/forums/showthread.php?s=&threadid=1518577

[ReefFreek917]

I have 2 ultra blues and both extend the same way. I have 2 400w MH over my 75 and both clams are midway in my tank. I dont think its just a "I need more light" thing. Mine look great and have been in there for almost a year. They just like to extend.



Caleb

[Bonneville08]

I don't have a lot of experience with Tridacnas, having only one Crocea under MH lighting, but I was under the impression that the biggest concerns involved bleaching or gaping. If the mantle is well colored completely and the inhalant siphon is not stretched out, you may be OK.
Extra lighting would probably not hurt if the clam is deeper in the tank, but would watch for signs of central bleaching if the intensity is suddenly increased.
This is obviously not the most popular opinion on this thread, but I still consider it valid.

[LCDRDATA]

First, thanks to everyone for your continued input.

Second, I've cross-posted this thread on the Tridacnid Clams and other Mollusks forum and had a couple of requests for a top-down shot. Unfortunately I saw those requests AFTER :( I'd dosed the tank with Liquid Calcium Reactor so the water is somewhat murky and this isn't the best - I'll try and get a better shot tomorrow

http://reefcentral.com/gallery/data/500/194807hypermantle_5.jpg

I'll admit to being a little conflicted at this point - it's really not clear to me whether light is the issue or not, or even if there is an issue (if ReefFreek917's 800 watts of MH aren't enough to keep one from extending like this, I don't know what would be!). What I have done since I got home from work today is add the 26W 6500K spot I mentioned earlier, and added a pump and flow enhancer to my inlet to significantly increase the overall flow in my tank. Hopefully the photo above - or the one I hope to post tomorrow - will provide a better guide to how this clam is doing. Thanks for the help - please keep it coming!

[ducatimikep]

We also have a Croesus clam in our tank.
It is 10" below the surface of 8 - 54w T5's.
It is extended as yours is. He has been there
For 6 months like this with no moving around
So I assume that he is happy. He looks healthy.
So maybe they just like to extend & there really
Isn't a problem? Ours like to extend late in the afternoon,
If that makes a differance.

[LCDRDATA]

First of all, here's a much better shot looking straight down -

http://reefcentral.com/gallery/data/500/194807hypermantle_6.jpg

Second, a respondent on the other thread asked a number of questions; as they are reasonable I'm cross-posting my answers here as well:

how much liquid Ca are you adding???

Generally, I dose KentMarine Liquid Calcium about twice a week per the label directions.

do you add an ALK as well??

Yes; generally, I dose KentMarine ProBuffer dKh about three times a week per the label directions. The product I used last night is a combination calcium and alk source. I also dose magnesium (stock solution mixed from flake) weekly.

how and where and when do you add them??

I measure them out with a graduated cylinder and add them to the sump where the current can mix them a bit more before they hit the intake. The ProBuffer directs to add in the morning, and I generally dose the calcium either a few minutes later or that evening. The product I used last night recommends dosing in the evening, so that's when I dose with it. I'm not using it as often (I'm running out, while I have plenty of the other two products), but I like to use it when I'm changing my flow because it provides a good visual.

the rolling down of the outside edge of the mantle leads me to believe there is and ALK problem but this wouldn't cause the clam to reach.

[I] please post all you test paramaters???

Temp: ~77
Salinity: 1.026
pH: 8.2
Ammonia, Nitrite, Phosphate: 0
Nitrate: 25 (working on it; coming off a spike and down considerably)
Alkalinity: 2.5 meq/l (dKh 7)
Calcium: 470
Magnesium: 1425

the mantle extension isn't the problem, it the fact that it isn't laying down on the shell, it is reaching for light.

can you ask reeffreek to post a pic of his clam??

ReefFreek917, could you do that please?

OK, hopefully that provides enough additional information to help figure this all out.

[LCDRDATA]

More good information & questions from the Clam forum and (hopefully) good answers and questions from me. Please look over both (I've put the other member's statements in italics) - I'm still interested in anything productive available on this thread as well.

OK, let me try to answer your questions and we'll hopefully get this figured out together. This is a rather lengthy, detailed post, so please be patient and read carefully. :)

try dosing the Ca and ALK slower, it shouldn't cloud the water like that.

For the Liquid Reactor, this kind of cloudiness is normal and expected. The other products don't cloud up like this.

your clam is turning white, there can be little doubt that your clam needs more light and fast. if you look at the mantle, you can see a few spots of blue left but the majority is turning a pale white.

For what it's worth, the good news here is that the clam is actually bluer "in person" than you can tell from the photo. I'm not disputing what you're saying, only that it's not quite as desperate as it appears.

you need to increase the amount of light the clam is getting immediately. it needs to be done very carefully at this point to not shock the clam as this may cause him to dump the remaining zoox., which could be fatal.

This is where it gets a little tricky. How much can we increase the lighting, how fast? Hold that thought - more discussion down a little farther.

can you post a pic of your lighting fixtures?

http://reefcentral.com/gallery/data/500/194807Aqualight_T5.jpg

http://reefcentral.com/gallery/data/500/194807Aqualight_T5_closeup.jpg

do they have individual reflectors??

As you can see, there's no room for individual reflectors. However, as may (or may not) be apparent, the entire inside surface around the bulbs is reflective (I'm guessing aluminized mylar, but that's only a guess), so the vast majority of generated light is going into the tank.

how old are the bulbs?? what kelvin are they?

Three of the four bulbs are less than six months old - the actinic (420 nm) and two of the 10,000K bulbs. The other 10,000K bulb is a year or so old - looking at the fixtures turned so the bulbs are facing up, it looks as though its light output is fairly close to the other 10,000K bulbs.

That's the good news. The bad news is that while I thought these were all 54W bulbs, as it turns out only the older bulb is 54W. The newer bulbs are all 28W bulbs. Again, hold onto that thought for now; we'll discuss more in a moment.

can you move him up??

As a practical matter, no.

http://reefcentral.com/gallery/data/500/194807hypermantle_depth.jpg

This illustrates what I said above in an earlier post. The ruler ends 1/4" or less below the surface of the water, and even with the top and the fixture thickness the bulbs are only about an inch from the surface. So you can see the clam is only about 5" from the lights, which provides not much potential for substantially increasing the available light by moving it higher in the tank. Which brings us to issue number two.

http://reefcentral.com/gallery/data/500/194807hypermantle_foot.jpg

As you can see, the clam has worked itself over a raised area so it's sort of straddling a projection in the rock, with its foot and byssal fibers on either side. It's fairly rough, so I can't see a good way to even consider cutting it off. We placed the clam a couple inches farther back, and over the course of about a week it moved itself to its present location, where it's been anchored ever since - call it two months.

So, the bottom line is that currently the clam is under 2x28W 10,000K, another 10,000K that's supposed to put out 54W but currently putting out about 28W, and a 28W actinic. Add to that a 26W 6500K CF bulb in a 5 1/2" round metal reflector directly over the clam, which got added yesterday - and is (as it turns out) a larger percentage jump than I thought it would be, as the output of that bulb is nearly the same as the other individual bulbs but is concentrated on the clam. So there's already been a significant light increase, although admittedly not what will eventually be required.

Returning to earlier discussion points, the clam needs more light, but not so much more so rapidly that it dies from shock rather than lack of light. The immediate options I see (which aren't mutually exclusive) are as follows:

1) Increase the T5 output by putting replacing the 28W bulbs with 54W bulbs. This one is relatively straightforward - the one fixture already has a 54W bulb in it (although it's old enough that the output isn't where it should be). I've already paired that with a 54W actinic (vice the 28W). The downside of this is that I don't know how safe it is, given this is twice the power draw the unit was designed for. In fact, I've noticed that the clear acrylic cover over the 54W bulb is beginning to melt just over the joint where the glass meets the metal end cap. I also noticed that it's partially cracked there, so there may be something else going on that's responsible for the melting. Either way, that bulb's got to go, but it's unknown if that's a viable option overall.

2) Replace the actinic with another 10,000K bulb. That increases the white light from the two twin fixtures by 25% - my understanding is that while the actinic is pretty, it really does almost nothing in terms of photosynthesis. As I mentioned, for tomorrow I've already swapped out the 28W actinic for a 54W, but that's as much to see how the fixture deals with two 54W bulbs as it is for light output.

3) Increase the time. Right now, my timing cycle is 10am to 10pm, with the actinic/white combo on at 10, the twin white on at 12 and off at 8, and the actinic/white combo off at 10pm. I've put the 26W spot on the same timer as the actinic/white combo. Resetting the timer to have the full set on for a longer period would increase the effective light, although there's obviously a limit (and potentially diminishing returns) with this approach.

4) Add another 26W 6500K CF. While this is only a stop-gap, and isn't actually equivalent to 54W of 6500K (due to the diameter of the parabolic reflectors - I'm guessing effectively about 40W total), it's quick and easy.

5) Add yet another 26W6500K CF by removing enough of the black tank background to aim its reflector through the back of the tank onto the clam. It would be somewhat farther than from the top, but probably still not more than a foot from the focused bulb to the clam. This would also be obnoxious in the long run, but probably bearable for a little while.

I'm hoping some combination of these will do the job until we see which (if any) are viable and sufficient over the longer term, or a better solution can be worked out. However, assuming the existing fixtures can handle the additional power requirement, by doing all five of these we could easily triple or quadruple the light on the clam literally overnight. And most likely kill it from the shock in the process (not to mention what it might do to the rest of the zooanthellate population of the tank - probably the same).

So, with all these factors/alternatives in mind, how fast can we safely increase the light so as to return the clam to health without causing it and the rest of the tank undue shock and stress? Which steps should we add, and in which order? What do you think?

[Juruense]

Those bulbs look pretty shot. You need bulbs with individual reflectors and more of them.

You have room for bulbs with individual reflectors because the reflectors are actually inside the bulb.

I bet you have a problem with algae growth with those old bulbs also...

[LCDRDATA]

Algae hasn't been a problem since I got the phosphates down and nitrates getting there. And I've learned something about individual reflectors as well. I'm assuming such bulbs are labeled as having them; are those only VHO bulbs, and do they need special ballasts?

Any ideas on the rest of my options (or ideas for options I didn't list)? Thanks!

[ReefFreek917]

LCDRDATA,

I appreciate your commitment to improving the conditions for your clam. Here is a top picture of the smaller of my 2 clams. As you can see he is fully extended. At the time of this particular picture he was not as extended as he has been before. Here is my input:

http://s280.photobucket.com/albums/kk197/ReefFreek917/?action=view&current=100_5635.jpg

1) Your clam is a little over extended. This is most likely due to it reaching for more light and trying to filter better. Remember that clams are also filter feeders so light is not all it needs.

2) Try feeding your tank by using reef chili or a mysis/brine shrimp soup.

3) Kent marine calcium sucks. Ditch that junk. ReefBulkSupply.com has a great 2 part solution for calc & alk. Unless you have a lot of SPS I would maybe just do water changes and not owrry to much about the calcium issues. Salt has enough to sustain 1 clam for each water change.

4) GET MH. Go to the used dry goods selling forum. There are tons of single MH setups. I appreciate your attempts to beef up you lighting but spend the $200 on MH not CF.

Good Luck!



Caleb

[pammy]

Hmmm... my Crocea Clam looks like that, and I thought it was very healthy. The only time that my clam hasn't been extended like it is now (first picture below) is when I had a Coral Beauty Angel that was nipping at it a bit (see second picture below, same clam as first picture). As soon as I pulled the Coral Beauty out of the tank, the clam IMMEDIATELY opened way up and has stayed that way for the past 6 months. I've had my Crocea for 18 months now. It's at the bottom of my tank (it also was not attaching up on my rocks). Tank is 19.5" deep, and I have a Elos Light fixture with a 12k Reflux MH bulb (changed from a Elos 10k MH bulb) and 4 24W T5 bulbs (2 x ATI Blue Plus , 1 UVL Super Actinic and 1 UVL AquaBlue). I'm assuming I have plenty of light for it. Pam

CROCEA Clam AFTER pulling Coral Beauty out of tank. Still looks
this extended 6 months after pulling out Coral Beauty:
http://s203.photobucket.com/albums/aa157/matsis1234/?action=view&current=TankCroceaClamAug08.jpg

Crocea Clam when Coral Beauty was nipping it:
http://s203.photobucket.com/albums/aa157/matsis1234/?action=view&current=CroceaClam.jpg

[ReefFreek917]

Love the sun coral pammy.

[pammy]

Thanks ReefFreek. It's one of my favorite corals. It has quite a few more heads now. :)

<a href=showthread.php?s=&postid=13852226#post13852226 target=_blank>Originally posted</a> by ReefFreek917
Love the sun coral pammy.

[pammy]

Here's a photo I just took of my Crocea tonight. I didn't mention that the MH I have is a 150W (and 4 24W T5's) The light fixture is a high end Elos, with high end reflectors. I think the mantel is even a little more extended than in this photo. It was the second photo I snapped, so he hadn't quite extened back after the flash went off.



<a href=showthread.php?s=&postid=13852095#post13852095 target=_blank>Originally posted</a> by pammy
Hmmm... my Crocea Clam looks like that, and I thought it was very healthy. The only time that my clam hasn't been extended like it is now (first picture below) is when I had a Coral Beauty Angel that was nipping at it a bit (see second picture below, same clam as first picture). As soon as I pulled the Coral Beauty out of the tank, the clam IMMEDIATELY opened way up and has stayed that way for the past 6 months. I've had my Crocea for 18 months now. It's at the bottom of my tank (it also was not attaching up on my rocks). Tank is 19.5" deep, and I have a Elos Light fixture with a 12k Reflux MH bulb (changed from a Elos 10k MH bulb) and 4 24W T5 bulbs (2 x ATI Blue Plus , 1 UVL Super Actinic and 1 UVL AquaBlue). I'm assuming I have plenty of light for it. Pam

CROCEA Clam AFTER pulling Coral Beauty out of tank. Still looks
this extended 6 months after pulling out Coral Beauty:
http://s203.photobucket.com/albums/aa157/matsis1234/?action=view&current=TankCroceaClamAug08.jpg

Crocea Clam when Coral Beauty was nipping it:
http://s203.photobucket.com/albums/aa157/matsis1234/?action=view&current=CroceaClam.jpg

[pammy]

Here's a photo I just took of my Crocea tonight. I didn't mention that the MH I have is a 150W (and 4 24W T5's). Bulbs were all replaced this summer. The light fixture is a high end Elos, with high end reflectors. I think the mantel is even a little more extended than in this photo. It was the second photo I snapped, so he hadn't quite extened back after the flash went off. I don't know, but to me, my clam looks healthy, and at 18 months like this in my tank, and he stays put in one spot, he must be doing ok??? Maybe he just likes to show off his beautiful mantel??? ;)

]http://s203.photobucket.com/albums/aa157/matsis1234/?action=view&current=CroceaClam12-1-08.jpg





<a href=showthread.php?s=&postid=13852095#post13852095 target=_blank>Originally posted</a> by pammy
Hmmm... my Crocea Clam looks like that, and I thought it was very healthy. The only time that my clam hasn't been extended like it is now (first picture below) is when I had a Coral Beauty Angel that was nipping at it a bit (see second picture below, same clam as first picture). As soon as I pulled the Coral Beauty out of the tank, the clam IMMEDIATELY opened way up and has stayed that way for the past 6 months. I've had my Crocea for 18 months now. It's at the bottom of my tank (it also was not attaching up on my rocks). Tank is 19.5" deep, and I have a Elos Light fixture with a 12k Reflux MH bulb (changed from a Elos 10k MH bulb) and 4 24W T5 bulbs (2 x ATI Blue Plus , 1 UVL Super Actinic and 1 UVL AquaBlue). I'm assuming I have plenty of light for it. Pam

CROCEA Clam AFTER pulling Coral Beauty out of tank. Still looks
this extended 6 months after pulling out Coral Beauty:
http://s203.photobucket.com/albums/aa157/matsis1234/?action=view&current=TankCroceaClamAug08.jpg

Crocea Clam when Coral Beauty was nipping it:
http://s203.photobucket.com/albums/aa157/matsis1234/?action=view&current=CroceaClam.jpg [IMG

[LCDRDATA]

ReefFreek917, Pammy -

You've both got beautiful clams. I'm not quite ready to try metal halides because something whatever causes the shimmering effect triggers migraines for my wife, and she'd like to be able to look at the tank, too. In fact technically it's her clam. If I could experiment with a relatively low-power MH fixture I might go that route - I think I saw a 70W HQI online somewhere - but I doubt if the LFS (let alone an online retailer) is going to let me "test-drive" one for a month and return it, and I'm not willing to shell out $270 for such an experiment that would likely fail. As for the spot(s), the CF bulbs are just standard GE/Home Depot variety in a 5.5" aluminum reflector. I just made sure to get a 6500K color temperature. They're certainly not a long term solution, just something to start (if only minor) improvement or at least stabilize the situation/keep it from getting worse.

I don't think feeding is a problem - I've got a number of other filter feeders in the tank (both phytoplankton specialists like the clam and more zooplankton types) and they're all happy. As I think I said earlier in the thread I spot-feed a couple times a week, and then leave the skimmer turned off for an hour or so afterwards to keep the phyto in the water column. We had a withered little gorgonian that we got on a piece of live rock setting up the tank and it's growing like a weed.

Back to lighting, at this point I've got two 54W T5HO lights (one "Marine-Glo" actinic, and one "Life-Glo" 6700K) in one of my twin fixtures, plus the 26W 6500K spot directly on the clam. My wife thinks it's blue-ing up a little. The fixture case with those is definitely warmer than the one with the two 28W standard T5s (both 10,000K), but I don't think it's dangerously so. So I've already bumped up the light a fair amount (although not enough for the long run).

My thought is to leave the setup as it is for something like several days to a week before the next increment in light increase - the last thing I want to do is bleach it by jumping too fast. If all is still going well with the twin fixture with the 54W HO bulbs, I'll swap out the 28W bulbs in the second fixture for 54W HO bulbs. What do you think?

One other related question on the dry goods (buy/sell/trade) forums - do you know if there's any way to use a search function on those? There are a bazillion threads. Thanks!

[LCDRDATA]

Well, two developments today. First, the clam decided to let go of the rock it was on all by itself - I'll try to post a picture tomorrow, but right now it's sitting on the sand on top of a small coral fragment we want it to attach to, which should then allow us to place it wherever we want (potentially a tiny bit higher in the tank - although per the previous discussion, there's not much room to climb from where it was). We're putting as much light on it as we can (one of the 26W parabolic reflector units is now shining through the front of the tank about 2" from the clam), but overall it's losing some light until it attaches and we can move it again.

Second, I found a couple half-price(?) specials at HelloLights.com for 48" T-5 HO fixtures - both a 4x54W and an 8x54W unit. So my question is, is the 4x unit enough light, or do I need the 8x unit? Does this answer apply wherever the clam ends up in the tank, or does it need to stay near the top, and is that answer the same for both units? In other words, which unit allows enough light for what kind of placement? - please answer for the 4x unit and for the 8x unit. It looks like the clam is getting lights for Christmas!:D Thanks again!

[LCDRDATA]

Well, we put the clam back where it was, and now it's been about 2-3 weeks since I got the 8-bulb T-5HO unit. Here are a couple shots of the clam today:

http://reefcentral.com/gallery/data/500/194807lighted_clam.jpg

http://reefcentral.com/gallery/data/500/194807lighted_clam_2.jpg

As you can see, the mantle is still greatly extended, but there's much more color generally and blue specifically in the mantle. I think it's going to be all right now, but I wanted to close the loop on this thread. Thanks to everyone for all your help.

[slimy fish]

My vote is more light. Make sure to keep your water crystal clear with carbon or ozone. It won't matter how much light you have if your water is tinted from organics.

[jedheuer]

Way to go LCDRDATA. 8 hoT5 should be plenty of light for your clam (and anything else for that matter). Just be sure to run good bulbs, I am not sure what comes with the unit you got but there can be quite a bit of difference when it comes to individual bulb manufactures. ALso check out the T5 thread if you havent already.

http://reefcentral.com/forums/showthread.php?s=&threadid=1527167