Losing My Corals

[chatyak]

Please help. I don't know what the issue is here. Only some of my SPS are having their tissue go away... albeit at a snails pace... its been at least 2 months for what you see in the pictures to have happened.

Salinity normally at 1.025 with calibrated refractometer... use reef crystals. Nitrates et al. all in check... I use high capacity GFO from BRS... normal water changes etc.... no drastic changes in water chemistry.... other SPS doing fine... see images attached. :strange:


http://i241.photobucket.com/albums/ff141/chatyak/100_5153.jpg

http://i241.photobucket.com/albums/ff141/chatyak/100_5152.jpg

http://i241.photobucket.com/albums/ff141/chatyak/100_5151.jpg

http://i241.photobucket.com/albums/ff141/chatyak/100_5150.jpg

http://i241.photobucket.com/albums/ff141/chatyak/100_5149.jpg

http://i241.photobucket.com/albums/ff141/chatyak/100_5148.jpg

http://i241.photobucket.com/albums/ff141/chatyak/100_5147.jpg

http://i241.photobucket.com/albums/ff141/chatyak/100_5146.jpg

http://i241.photobucket.com/albums/ff141/chatyak/100_5145.jpg

[chatyak]

It should be noted that the larger acro is where there was a hairy green crab, which I had removed - however it has been gone for some time..

Here are more pictures:

http://i241.photobucket.com/albums/ff141/chatyak/100_5144.jpg

http://i241.photobucket.com/albums/ff141/chatyak/100_5143.jpg




Now here are a couple of the healthy ones.


http://i241.photobucket.com/albums/ff141/chatyak/100_5157.jpg

http://i241.photobucket.com/albums/ff141/chatyak/100_5156.jpg

http://i241.photobucket.com/albums/ff141/chatyak/100_5155.jpg

http://i241.photobucket.com/albums/ff141/chatyak/100_5154.jpg


Thoughts?

[REEF SMAC]

What is your Alk level and how consistant is it?

What is your Phosphate level?

What kind of flow are they getting?

[chatyak]

What is your Alk level and how consistant is it?

What is your Phosphate level?

What kind of flow are they getting?


I do my best to do small weekly water changes and the ALK on the water bin is usually:

dKH 11
CA 500-550
MG 1500-1600


I only have about 5-8 SPS corals, and some LPS... so I don't dose daily... but perhaps I should? I would have thought that the ALK change over the course of a week was minimal... then with small water changes, not a drastic effect.

What do you suggest for course of action? Measure dKH and then measure again in 5-6 days to see how much it is dropping each day?


Phosphates I have not tested in a long time. I have the Hanna photometer with the digital readout and it has always read 0... so "undetectable" or super minimal. I did have a cyano problem a couple of months ago but have reversed that and its 99.5% gone. Had a bacteria unbalance in the tank.

I have two MP40w ES's. One on either side of the tank. They are nice.. but truth be told I think I would add controllable Tunze's in the future. Perhaps I should throw in some Koralias too?

[rogerwilco357]

wow i have the same problem today on a millepora and on an acro like yours the yellow one not sure if the gfo has something to do with it but i just put new gfo in also two weeks ago and this started shortly after but my phosphates are high also out of 8 sps only 2 have been affected hope you find out the problem will keep track of this post.

[daz the reefo]

look like signs of alkalinity swing stress to me.

[Bevin]

How much gac do you use? I stopped using it all together and have never had that problem again.

[Met3112]

Check to see if there is anything eating them. I think your other acros would be stressing if it was alk swings, though stable alk is very important.

Look for asterina stars, especially the blue ones. I have caught these chowing down on my pocillaporas and seriatoporas. And for the person who is about to deny that: No they were not eating the dead flesh they actually eat coral.

Have you dipped any of these to see if anything fell off?

[REEF SMAC]

I do my best to do small weekly water changes and the ALK on the water bin is usually:

dKH 11
CA 500-550
MG 1500-1600


I only have about 5-8 SPS corals, and some LPS... so I don't dose daily... but perhaps I should? I would have thought that the ALK change over the course of a week was minimal... then with small water changes, not a drastic effect.

What do you suggest for course of action? Measure dKH and then measure again in 5-6 days to see how much it is dropping each day?


Phosphates I have not tested in a long time. I have the Hanna photometer with the digital readout and it has always read 0... so "undetectable" or super minimal. I did have a cyano problem a couple of months ago but have reversed that and its 99.5% gone. Had a bacteria unbalance in the tank.

I have two MP40w ES's. One on either side of the tank. They are nice.. but truth be told I think I would add controllable Tunze's in the future. Perhaps I should throw in some Koralias too?

It's good to know what the levels are in the water bin, but what are the levels in your DT? If your DT Alk is running on the low side at say 7.0 (and it might be at 6.0) and your doing water changes with water that is at 11.0 then maybe it's swinging your levels a little too much. Low Alk coupled with a new batch of GFO could definately cause what you're seeing. You might want to back off the GFO use, or at least lower the amount, as you might be overstripping your water with it. Especially if your Phosphate is already at 0.
Are you carbon dosing at all?
I would just for a while, be checking your Alk everyday, for a few days, just to get an idea what's going on. Check it before a water change and then the next day after a water change. Check it berfore you dose and then a while after. Check it 12 hours after you do a GFO change.

It's the fast daily changes that are the problem not the changes that take place over 5-6 days.

I agree with daz on this one.

[chatyak]

It's good to know what the levels are in the water bin, but what are the levels in your DT? If your DT Alk is running on the low side at say 7.0 (and it might be at 6.0) and your doing water changes with water that is at 11.0 then maybe it's swinging your levels a little too much. Low Alk coupled with a new batch of GFO could definately cause what you're seeing. You might want to back off the GFO use, or at least lower the amount, as you might be overstripping your water with it. Especially if your Phosphate is already at 0.
Are you carbon dosing at all?
I would just for a while, be checking your Alk everyday, for a few days, just to get an idea what's going on. Check it before a water change and then the next day after a water change. Check it berfore you dose and then a while after. Check it 12 hours after you do a GFO change.

It's the fast daily changes that are the problem not the changes that take place over 5-6 days.

I agree with daz on this one.


To the fellow who asked about predators... I have looked at the corals and not noticed anything that is eating them ( granted I don't have a microscope).

My total water is around 146 gallons.. and for the GFO I used about 30% of a Phosban 550. Change it out every 4-6 weeks. I wouldn't have thought the phosphate is at 0, due to a minimal trace of cyano left, but perhaps all the available phosphate has been used.

I used to use ROX carbon from BRS as well - but haven't in some time mainly because I couldn't afford it at the moment.

When I do my water changes - I can only change out about 10 gallons at one time, unless I do that a few times in one day (after waiting a few mins for water from sump to get circulated around). So unless I did a lot of water changes at once, I'm not sure how much of an effect the alk would have.

Also - could you explain why to go easy on the GFO - when lower phosphates is what we are aiming for? Are you saying that we should leave some phosphates in the water column? I understand that we don't want the water column to be bare of nutrients, but is not phosphate one of the "enemies" of the home aquaria?

I will go test my water params for the display tank now.


Also - should I dip these corals for a few mins? I have two little fishies revive solution.

[chatyak]

Low Alk coupled with a new batch of GFO could definately cause what you're seeing. You might want to back off the GFO use, or at least lower the amount, as you might be overstripping your water with it.

Could you explain why a new batch of GFO is a bad thing? Because it is a sudden shock of lower phosphates - this in turn affects the corals?

[chatyak]

Okay I have some interesting news to report!

Water Bin Params
---------------
dKH: 11.3
CA: 530 ppm
MG: 1500 ppm
PO4: Not Tested
SG: 1.0265



Display Tank Params
-------------------
dKH: 6.3
CA: 425 ppm
MG: 1410 ppm
PO4: .09 ppm
1.0230



So now the question is - should I be dosing daily or are weekly water changes enough? I think the course of action now is to get the dKH and CA up (and MG) in the display, and then wait 3-4 days and see how far it is dropped. Then I can divide by 3-4 to see what the daily dose is.

I am leaving in 9 days for just over a week though. Would like to get this sorted before then. :sad1:

[mthomp]

Could you explain why a new batch of GFO is a bad thing? Because it is a sudden shock of lower phosphates - this in turn affects the corals?
When you add GFO to your system the GFO will lower your alk pretty drastically. Something I would check is the TDS of your RO water. I had something like this happen to me and that was the culprit.

[chatyak]

When you add GFO to your system the GFO will lower your alk pretty drastically. Something I would check is the TDS of your RO water. I had something like this happen to me and that was the culprit.

I have read that the effect is minimal with regards to alkalinity being lowered by GFO. Why do you say drastically? How much of a change would GFO normally reduce? 1-2 on the dKH?

Also - is the reduction in dKH ongoing or simply when you introduce a new batch of GFO?

[Randy Holmes-Farley]

With those SPS corals (which are high alk users) and no alkalinity additions other than water changes, it is zero surprise that the alk has dropped to 6 dKH, and also not a surprise that the corals are not doing well at 6 dKH, which is very stressful.

Alkalinity additions are a must for SPS tanks. Water changes cannot ever maintain alkalinity in such a system unless you are changing on the order of 20-50% daily.

I show that here:

Figure 23. Alkalinity as a function of time when performing very large daily water changes of 0% (no changes), 5%, 10%, 15% and 30% of the total volume EACH DAY. In this example, alkalinity is present at 4 meq/L (11 dKH) at the start and is depleted at a low rate of 0.2 meq/L per day.

http://reefkeeping.com/issues/2005-10/rhf/images/Figure23sm.GIF

Figure 24. Alkalinity as a function of time when performing very large daily water changes of 0% (no changes), 15%, 30% and 50% of the total volume EACH DAY. In this example, alkalinity is present at 4 meq/L (11 dKH) at the start and is depleted at a moderately high rate of 1 meq/L per day.

http://reefkeeping.com/issues/2005-10/rhf/images/Figure24sm.GIF

[MammothReefer]

I would either dose daily or better yet set up some sort of automated system to do it for you. Be it dosing pumps, or a calcium reactor. SPS require very minimal movement in alk (which can't be achieved without consistent calcium/mag). Ideally I shoot for less then .2dkh swing a day. I'm sure less is even better but I find even the smallest variance in testing can fluctuate by .1dkh or so.

[chatyak]

Dosing pumps will be installed next week.

[dowtish]

Your salinity is low as well. I would shoot for 1.025-26. Also, what kind of lights do you have over the tank?

[chatyak]

Your salinity is low as well. I would shoot for 1.025-26. Also, what kind of lights do you have over the tank?

I try to keep it at 1.025.. just got low on me... letting it rise on its own with no ATO for the time being.

I use T5 lighting :)

[REEF SMAC]

Could you explain why a new batch of GFO is a bad thing? Because it is a sudden shock of lower phosphates - this in turn affects the corals?

It's not so much the shock of lower phosphates as it is the shock of lower Alk that the GFO seems to cause.
Could be the phosphates too I guess if your system were already at zero.

Okay I have some interesting news to report!


Display Tank Params
-------------------
dKH: 6.3
CA: 425 ppm
MG: 1410 ppm
PO4: .09 ppm
1.0230



So here is what I would guess has been why your corals are unhappy.
Your Alk is way lower than I would want it. I like to shoot somewhere between 8 - 9.
Your PO4 is a little high. Not deathly high but stressful. I would get it at least under .05.
Your salinity is a little low. I seem to have better results with it closer to 1.026.

I have read that the effect is minimal with regards to alkalinity being lowered by GFO. Why do you say drastically? How much of a change would GFO normally reduce? 1-2 on the dKH?

Also - is the reduction in dKH ongoing or simply when you introduce a new batch of GFO?

Depending how much GFO relative to your system size, the quality of the GFO, and even the reactor flow rate, would change how much the Alk level is affected.
If your Alk is already too low (which seems to be the case with yours) and then you throw in some new GFO and pull the Alk down even lower. It's probably not gonna go to well for your corals.

The Alk drop with new GFO seems to just last a few days for me. After that is seems to be at the normal level.

Sounds like you need to get you levels up and then find a way to keep them a lot more consistant. Which will probably be at least daily dosing.

:)

[chatyak]

It's not so much the shock of lower phosphates as it is the shock of lower Alk that the GFO seems to cause.
Could be the phosphates too I guess if your system were already at zero.



So here is what I would guess has been why your corals are unhappy.
Your Alk is way lower than I would want it. I like to shoot somewhere between 8 - 9.
Your PO4 is a little high. Not deathly high but stressful. I would get it at least under .05.
Your salinity is a little low. I seem to have better results with it closer to 1.026.



Depending how much GFO relative to your system size, the quality of the GFO, and even the reactor flow rate, would change how much the Alk level is affected.
If your Alk is already too low (which seems to be the case with yours) and then you throw in some new GFO and pull the Alk down even lower. It's probably not gonna go to well for your corals.

The Alk drop with new GFO seems to just last a few days for me. After that is seems to be at the normal level.

Sounds like you need to get you levels up and then find a way to keep them a lot more consistant. Which will probably be at least daily dosing.

:)


Randy homes was saying that the alk should not drastically drop - if at all... to a noticeable point. Perhaps with a lot of GFO relative to the tank size this may be a factor? I will measure the dKH before I change out the GFO and then measure it again the next day and see what it says.

If I am daily dosing, the dKH should still drop if the GFO is the culprit....

[REEF SMAC]

Randy homes was saying that the alk should not drastically drop - if at all... to a noticeable point. Perhaps with a lot of GFO relative to the tank size this may be a factor? I will measure the dKH before I change out the GFO and then measure it again the next day and see what it says.

If I am daily dosing, the dKH should still drop if the GFO is the culprit....

I will definately not be the one to argue with the RC chemistry God that GFO will be the direct cause of an Alk level drop.

I can tell you that with my personal system, when I change out my GFO, I can count on my Alk to drop at least 1 dKH in the next 24 - 48 hours.
I honestly don't know if that is attributed to the GFO itself somehow absorbing Alk. I'm only guessing that's a small part of it.
I would love to know honestly.

I think the other part and probably the biggest reason for the drop in Alk is the fact that the PO4 level dropping (due to the GFO absorbing it) causes your corals to grow faster, a little growth spurt, therefore depleting the Alk out of your water faster. Next thing you know, your Alk is down to 6.

It's coral growth more than anything else that's depleting your Alk level. It's not that the GFO is constantly using it up by any means. GFO is not the "culprit". It's just another part of the overall equation.

You need to be adding Alk (Ca & Mg) to your system at the same rate as your corals are using it up. You will probably need to do daily water testing for a short time to find out what exactly the dosing rate is for your system.
The closer you can get to matching your dosing rate, with the rate your animals are using it up, the better. That is how you keep your params stable.
The more stable your water params are, the better your corals are gonna be looking and growing IME.
:)

[chatyak]

I will definately not be the one to argue with the RC chemistry God that GFO will be the direct cause of an Alk level drop.

I can tell you that with my personal system, when I change out my GFO, I can count on my Alk to drop at least 1 dKH in the next 24 - 48 hours.
I honestly don't know if that is attributed to the GFO itself somehow absorbing Alk. I'm only guessing that's a small part of it.
I would love to know honestly.

I think the other part and probably the biggest reason for the drop in Alk is the fact that the PO4 level dropping (due to the GFO absorbing it) causes your corals to grow faster, a little growth spurt, therefore depleting the Alk out of your water faster. Next thing you know, your Alk is down to 6.

It's coral growth more than anything else that's depleting your Alk level. It's not that the GFO is constantly using it up by any means. GFO is not the "culprit". It's just another part of the overall equation.

You need to be adding Alk (Ca & Mg) to your system at the same rate as your corals are using it up. You will probably need to do daily water testing for a short time to find out what exactly the dosing rate is for your system.
The closer you can get to matching your dosing rate, with the rate your animals are using it up, the better. That is how you keep your params stable.
The more stable your water params are, the better your corals are gonna be looking and growing IME.
:)

Sound advice indeed :) I would agree with your analysis. Now what about the coral turning brown?

In the pictures it is a bit hard to tell - but in person, the coral is now turning brown where it was white or had tissue loss.

Is this the coral re-growing back in some tissue and its brown at first? Or is this some form of algae now growing on the coral since the tissue was lost?

[Randy Holmes-Farley]

An additional way that GFO can cause an apparent alk loss is that reduced phosphate may spur certain calcifying organisms to grow faster. Coralline algae and such, for example. :)

FWIW, it is clear that GFO spurs abiotic precipitation of calcium carbonate, as I mentioned, and that can lower alk. :)

[chatyak]

Thank you sir. So it seems I shouldn't be too worried about the small change in alk when adding GFO - since even if it drops 1-2 dKH, that level is replenished in time with a water change and the dosing... I would think?

Start with 10dkH.... add GFO - drop 1 dKH... now at 9.... dosing keeps it around 9.... do a water change.... goes slightly higher.... etc...

Seems like in the very long run... you may need to manually top up the dKH - or simply top up dKH when you change out the GFO :bounce1:


On a side note - will my corals regrow and what exactly is the brown area on the coral? Is that re-growth or is that some form of algae now covering the once live tissue?

[Randy Holmes-Farley]

Most people do not connect alk dosing to GFO changes because they do not notice enough of an effect to be significant.

But you do need to frequently measure and dose alk in an SPS tnak. :)

[chatyak]

So I tested the params and used the reef calculator on BRS to determine my dose based on water volume - for how much I needed to raise the dKH and CA.

Yesterday was:

dKH: 9.5
Ca: 550


I only dosed the alkalinity portion----- 104ml of Recipe 1 using BRS material (soda ash in a 1 gallon jug of rodi). The calculator said it would bring it up to 10.5

Today I measured and:

dKH: 9.8
CA: 535


I thought it was odd at first... but tested twice and it came to 9.7 or something... so it's on the mark.... my guess is - that the initial dose to raise it was not enough, due to the tank using up the dKH over the course of the day.

So based on my calcium measurement, even by being off by .2 (equaling 10ppm).... to go up or down 1dKH requires about 100ml (for my estimated water volume of 146 gallons) .... and to go from 545 to 535 requires about 100ml of the CA... so it would appear I require 100ml per day of dosing.

Is this on the right track? I think so.... :bounce3:


I will measure again tomorrow at the same time with no dosing until then.

[TprMoore]

So I tested the params and used the reef calculator on BRS to determine my dose based on water volume - for how much I needed to raise the dKH and CA.

Yesterday was:

dKH: 9.5
Ca: 550


I only dosed the alkalinity portion----- 104ml of Recipe 1 using BRS material (soda ash in a 1 gallon jug of rodi). The calculator said it would bring it up to 10.5

Today I measured and:

dKH: 9.8
CA: 535


I thought it was odd at first... but tested twice and it came to 9.7 or something... so it's on the mark.... my guess is - that the initial dose to raise it was not enough, due to the tank using up the dKH over the course of the day.

So based on my calcium measurement, even by being off by .2 (equaling 10ppm).... to go up or down 1dKH requires about 100ml (for my estimated water volume of 146 gallons) .... and to go from 545 to 535 requires about 100ml of the CA... so it would appear I require 100ml per day of dosing.

Is this on the right track? I think so.... :bounce3:


I will measure again tomorrow at the same time with no dosing until then.

FWIW it's worth I too use BRS recipe 1 for my two part needs and although their calculator is helpful, there are variables when mixing. For example, your 2 level cups of soda ash, might not really be level or you may have put more water in which ends up diluting the solution. After every new big batch of two part I mix, I always test for a few days to check the concentration of the new solution. HTH
batch.

[chatyak]

FWIW it's worth I too use BRS recipe 1 for my two part needs and although their calculator is helpful, there are variables when mixing. For example, your 2 level cups of soda ash, might not really be level or you may have put more water in which ends up diluting the solution. After every new big batch of two part I mix, I always test for a few days to check the concentration of the new solution. HTH
batch.

How do you check the solution for concentration?

[JMLewis]

What salt are you using?

I had the exact same issue when using D+D H2Ocean, my alk wasnt swinging, and all my parameters were perfect, same with the newly mixed water. The salt mix was the LAST thing i thought was the problem but as SOON as i tried a different salt mix everything started recovering...

I have a brand new bucket of it in the garage since i was doing so many water changes i was running out fast, but now im to scared to touch the stuff.

BTW selling fresh bucket of D+D H2Ocean...jk but yea it was something that none of my test kits could detect.

[chatyak]

What salt are you using?

I had the exact same issue when using D+D H2Ocean, my alk wasnt swinging, and all my parameters were perfect, same with the newly mixed water. The salt mix was the LAST thing i thought was the problem but as SOON as i tried a different salt mix everything started recovering...

I have a brand new bucket of it in the garage since i was doing so many water changes i was running out fast, but now im to scared to touch the stuff.

BTW selling fresh bucket of D+D H2Ocean...jk but yea it was something that none of my test kits could detect.

I stopped using DD. My salt bucket was filthy. I may have been mixing the salt in the water when the temp was too low - but either way I prefer Reef Crystals. Great parameters and it costs less.... and not a filthy bucket.

My typical batch values at 1.025 are:

dKH: 11ish
CA: 540ish
MG: 1540ish

[newsalt]

I'm having the same issue. I probably lost about 1/4 my SPS in my 180 gallon tank. It seems that it all started when I changed salt. I was using Seachem Reef Salt and switched to Red Sea Coral Pro.

[chatyak]

Well here are the past 3 days of tests....

May 28th 2012 / 550 9.5 (added dose to raise alk)
May 29th 2012 / 535 9.8
May 30th 2012 / 530-540 9.4
May 31st 2012 / 535-540 8.5




Two questions:

1) Why does the calcium not seem to be dropping much at all but the alk is?

2) Why did the alk go down by 0.4 one day and 1 the next? When figuring dosing, should I take the average? 1+0.4/2 = 0.7 etc..

I'm going to raise levels where I want them... then let the tank sit for a week and see how much it drops.



Add-on: Found this neat piece written by Randy: Could be the issue...

One of the interesting features of seawater is that it contains a lot more calcium than alkalinity. By this I mean that if all of the calcium in seawater (420 ppm; 10.5 meq/L) were to be precipitated as calcium carbonate, it would consume 21 meq/L of alkalinity (nearly 10 times as much as is present in natural seawater). In a less drastic scenario, let's say that calcium carbonate is formed from aquarium water starting with an alkalinity of 3 meq/L that it is allowed to drop to 2 meq/L (a 33% drop). How much has the calcium declined? It is a surprise to many people to learn that the calcium would drop by only 20 ppm (5%). Consequently, many aquarists observe that their calcium levels are relatively stable (within their ability to reproducibly test it), but alkalinity can vary up and down substantially. This is exactly what would be expected, given that the aquarium already has such a large reservoir of calcium.

So the first "deviation" from the rule of calcium and alkalinity balance really isn't a deviation at all. If an aquarist is supplying a balanced additive to his aquarium, and calcium seems stable but alkalinity is declining, it may very well be that what is needed is more of the balanced additive, not just alkalinity. This scenario should be assumed as the most likely explanation for most aquarists who should look for more esoteric explanations for alkalinity decline only if calcium RISES substantially while alkalinity falls. Likewise, if alkalinity is rising and calcium seems stable when using a balanced calcium and alkalinity additive system, the most likely explanation is that too much of the additive system is being used.

So that may answer why my calcium seems stable but alk went down.... interesting indeed. The only thing I don't understand here is who should look for more esoteric explanations for alkalinity decline only if calcium RISES substantially while alkalinity falls.

[Randy Holmes-Farley]

Two questions:

1) Why does the calcium not seem to be dropping much at all but the alk is?

2) Why did the alk go down by 0.4 one day and 1 the next? When figuring dosing, should I take the average? 1+0.4/2 = 0.7 etc..



Number 1 is always the way. Even if the only process is calcium carbonate precipitation, each 1 dKH drop in alkalinity (an easily detected drop) is accompanied by only a 6-7 ppm drop in calcium, and the latter is not really even detectable with most kits. The reason the percentage drop inn calcium is so much lower is just that there is so much more calcium in seawater than alkalinity.


For number 2, one day is not really enough to get a good reading due to test kit variances, but there may be other issues as well. It is also much better to figure dosing by trial and error than by predicting the fall and then adding back because pH and alkalinity play a substantial role. For example, it may take a lot more supplement every day to maintain 11 dKH than 7 dKH in the same tank.

I don't think anyone should waste their time looking for other imbalanced demand causes, be here are some:

When Do Calcium and Alkalinity Demand Not Exactly Balance?
http://reefkeeping.com/issues/2004-12/rhf/index.htm

[chatyak]

Number 1 is always the way. Even if the only process is calcium carbonate precipitation, each 1 dKH drop in alkalinity (an easily detected drop) is accompanied by only a 6-7 ppm drop in calcium, and the latter is not really even detectable with most kits. The reason the percentage drop inn calcium is so much lower is just that there is so much more calcium in seawater than alkalinity.


For number 2, one day is not really enough to get a good reading due to test kit variances, but there may be other issues as well. It is also much better to figure dosing by trial and error than by predicting the fall and then adding back because pH and alkalinity play a substantial role. For example, it may take a lot more supplement every day to maintain 11 dKH than 7 dKH in the same tank.

I don't think anyone should waste their time looking for other imbalanced demand causes, be here are some:

When Do Calcium and Alkalinity Demand Not Exactly Balance?
http://reefkeeping.com/issues/2004-12/rhf/index.htm

Sounds good! I am leaving Sunday morning and will be away for 10 days... so I will start with a super-small dosing schedule and then recheck in 10 days. That will give the tank a good period of time to see what the level would be - what do you think?

That way, even if the levels do fall in the tank - the amount they fall is reduced and/or stalled by the small dosing.

Does this seem ok?

[DNA]

These are my weekly alkalinity numbers.
The one with a star * was measured about 2 hours after replacing the GFO.
Even though it was rinsed the fine particulates interfered with the test.
Next week it was back to normal.

9
11,2
10
10
10,7
10,6
10,4
13,5*
10,4
9,6
9,6
9,3
10,4
9,6
9,4

[Randy Holmes-Farley]

Sounds good! I am leaving Sunday morning and will be away for 10 days... so I will start with a super-small dosing schedule and then recheck in 10 days. That will give the tank a good period of time to see what the level would be - what do you think?

That way, even if the levels do fall in the tank - the amount they fall is reduced and/or stalled by the small dosing.

Does this seem ok?

Ah, it is hard to be away from a tank at a time like this.

You are probably already off.

Let us know what happens. :)

[rogerwilco357]

wow ten days Randy is correct your probably off now and it may not be nice when you come back you should leave your corals in a friends tank for the duration good luck..

[Reef_Newbie]

I have the same issue in my tank. The most noticeable ones are the pocillaporas which started to lose polyps from the base up. I do have a few questions that experts on this thread can probably answer them easily...

Can you dose just the Part 2 (alk) of the Two-Part products such as Reef Fusion or C-Balance to bring up Alk to the appropiate level? Or should it be something like 'food grade' baking soda, or do you prefer to use Seachem Reef Builder instead? There are so many products out there which claimed to raise alk level, but I am not so sure which method is best to, safely, bring up alk level over time without harming both corals and fishes. Thanks!

[Randy Holmes-Farley]

Yes, you can use just the appropriate half of a two part, especially for corrections. In general, however, unless calcium is already too high, I'd use both parts equally because calcium is just much slower to decline and so trying to track it with test kits is not trivial until the loss is substantial and you'll need to make up for many days of missed dosing. :)