Yeah... im not knocking the salt at all. if anything this shows that it does what they state its supposed to do. I guess its not a good salt for someone who is keeping LPS with no fish and small feedings. But we will see what happens in the next couple days... U dont think a water change would help?
Also, my phosphate dropped very quickly....
I agree with rtparty that clearer water can significantly increase light penetration and cause bleaching in corals, but I don't think you reported bleaching (only tissue loss).
How quickly did your po4 drop?? What were the readings and what was the timeframe?
The two possible problems I indicated (dropping nutrients too fast and having excessive nutrients) can be two of a few hundred problems that can induce coral stress exhibiting as tissue loss and coral death. With undetectable nitrate and a po4 of 0.02 then excessive nutrients isn't an issue (unless you have a massive amount of algae growing which can mask that actual amounts of nutrients present).
Can you give me a timeframe in which you started using the bioactif salt, started using the phosphate binder, and when you started seeing the tissue loss and coral stress?? Sometimes phosphate removers (GFO) can be too aggressive and cause coral stress. Are there any other significant changes you made since starting bioactif salt - change in feeding routine, dosing any other supplements, adding any other animals, etc....????
The coral stress and tissue loss may or may not be related to the bioactif salt. The organics in the bioactif salt may be contributing the root problem that is occurring or they may actually be the root problem. Tough to tell unless we work through this a bit further.
A common theory around dosing organic carbon sources is that it can cause abnormality in the growth rate of corals symbiotic bacteria. Hans hasn't clearly indicated that the organics that are contained in his salt mix are a carbon source but it sounds like that is what many people (including myself) have assumed.
Two very memorable times in which I had significant coral stress (and some coral death) was when I was dosing organic substances. One instance was when I was using the zeovit products and had been dosing too much of the carbon source. Not catching the signs and symptoms quick enough, because I was new to carbon source dosing, I ended up having many SPS and a few LPS corals (coincidently two chalices included) bleach and die. Once the carbon source dosing was backed down, the remaining living (but bleached and stressed) corals recovered. The second instance was when I was experimenting with amino acid dosing. I was using aspartic acid and after seeing initial positive results I decided to ramp up the dosing. Making dosing changes too quickly and with less than ideal caution, I ended up having very similar results as to when I dosed too much of the zeovit carbon source. Many corals bleached and a few died. Some corals also had tissue recession without bleaching. Once the aspartic acid dosing was stopped the tank slowly returned back to normal. I don't know if aspartic acid provides any significant amounts of carbon and I was under the impression that when dosing AA's the effect of overdose would be increased nitrates and increased algea growth. In both my examples, the issue was clearly related to the organic sources being dosed. Since we haven't the ability to measure the thousands of types of organics present in our tanks and we don't know exactly what organics are contained in bioactif salt, it seems quite logical to me that using the salt can cause imbalances in organic levels and cause negative consequences through various metabolic processes that occur in a reef environment. Since every tank is different and every situation is very different, it is often very tough to pinpoint the exact mechanism of action occuring that causes the coral stress and illness at times.
Making changes one at a time can help narrow down the issue at hand. If the coral stress began after starting the phosphate binder then I'd suggest removing the phosphate binder and monitoring results. If it started shortly after using bioactif salt then maybe resort to using your old salt mix for a month or two and observe the reaction.
I wouldn't recommend making any significant changes while corals are already stressed until you can more clealy identify the problem at hand. Sometimes we assume too quickly that the problem is factor X so we make a change to factor X when in reality (but unknown yet) the problem is factor Y. Now in making a change to factor X we could possibly induce coral stress from that change and we now have coral stress caused by factor X and factor Y.
Unless you have clear indication for it (noticing the coral stress shortly after starting bioactif would be a clear enough indication for me), I wouldn't make any big water changes but merely switch over to your normal salt mix (if your suspicious of the bioactif) and continue your normal water change routine. Because two salt mixes can contain drastically different amounts of elemental concentrations, making a big water change with a different salt mix can cause additional stress to the corals from the resulting elemental shift. If corals are bleaching then you may want to consider moving them lower in the tank to prevent further damage from the lighting while they have limited light protection, however I don't believe you indicated you noticed any bleaching.
Jeremy
