Need advice on lighting for corcea's

[guyguerra]

There are several threads about lights, but I didn't want to hi jack one, and I wanted to be specific about my system, so here's my set up question. I have 3 250 watt 20k MH's, 2 150 watt 10k VHO's and 2 150 watt Actinic. My tank is 26"deep with a 2" sand bed. I just bought my first corcea, and think it's the crown jewel of the tank. I placed him on the sand, as that's where I thought they went. I had some feed back from another post and moved him to the top of my LR structure so that he is 8" below the lights. He is also getting more flow up there, just enough to move his flesh gently. Is this the best spot for him? Is it possible to give them too mush light. He really looked better on the sand, because he contrasted nicely to the sand color. I will want to add another after I get used to keeping one. Do you think they would still thrive 26" below the lights with the amount of lights I have? I just added the halides, that's why I waited to get the clam. It seems like I have a LOT of light. 600 watts of VH's and 750 watts of MH's in a 220 gallon tank. That's about 6 watts a gallon. I also have seen posts that say you should use 10k instead of 20k (I do have the 2 10k VHO's though), but I also have other corals, and it seems like I should stay with the 20k's for the overall tank. Is this ok? Any advice would be appreciated. I'm new to clams, but think they are awesome.
Thanks, Guy

[mbbuna]

some people have success with clams and 20k lighting. so im not going to say that it cant be done. i dont recommend them because the spectrum of these bulbs is much bluer then what the clams would receive in the wild. so watch it closely and if it starts losing color then you may need to make a change.

anything can be exposed to too much light, but 250w MH for a Crocea isnt too much as long as the clam is acclamated slowly.

[eastcoastzigzag]

what is your opinion on 15k?

[guyguerra]

I forgot to mention, so I edited my first post. The VHO's that I have are 10k, would that help offset the 20k MH's?

[mbbuna]

<a href=showthread.php?s=&postid=6253950#post6253950 target=_blank>Originally posted</a> by eastcoastzigzag
what is your opinion on 15k?

in the wild these clams are found in shallow water with a full spectrum of light. the bulbs that duplacate a full spectrum of light are 6500k to 10k

[mbbuna]

<a href=showthread.php?s=&postid=6253958#post6253958 target=_blank>Originally posted</a> by guyguerra
I forgot to mention, so I edited my first post. The VHO's that I have are 10k, would that help offset the 20k MH's?

it wont really offset the 20k. if you take a 20k bulb and put a 10k next to it the light that goes into the tank wont be 15k. it will be 10k and 20k. the clam will be able to use the light from the 10k but VHO's dont drive the light in to the tank like a MH will so the clam would have to be higher to get to benefit from the VHO

[guyguerra]

Would you change to lower k bulbs in a full reef tank then? If so, which brightness. What do you use? Does your clam tank have corals also?

[mbbuna]

thats going to be up to you. i have 10k on both of my tanks

[guyguerra]

I'll start researching it to see what 10k does for corals and how it looks. It seems that a lot of people agree with you that 10k is better for clams.

[fishieness]

yeah, it definatly is. it is a much wider spectrum.
esspecialy blue clams. They are blue because the zoo is reflecting mostly blue light. This means that they are not absorbing mostly blue light. You can keep a clam under a 20000K bulbs, but it would have to acclimate to it over a periode of quite a while actualy.
sometimes, the clam doesnt have this long.

[eastcoastzigzag]

i will be going from a 150watt 10k to a 175 15k.......any acclimation needed?

[Ti]

been 20k for my clams for over a year now.

[guyguerra]

I had the owner of my LFS stop by my house yesterday to help me work on my canopy. He felt that with all the lights I have the clam would do fine on the bottom. That's where he keeps his, with about the same amount of lighting. My son said it well, he said "dad, your going to switch all your lights just because you bought 1 clam?" My fried from the LFS has 20k on his clams, so I'm going to stay with that unless I see a problem. If I do, my son will get a great deal on some slightly used 20k MH's. We'll see how it goes. I like the look that the 20k gives my tank a lot and haven't seen a tank with 10k yet. I'll keep my eye's out for one to see what it looks like.
Ti, I'm glad to see 20k is working for yours.