Coral Colours and Amino Acids

[Marlin65]

Originally Posted by Ron99

I do suspect my Alk may have been a bit unstable so I am keeping an eye on that right now. That may also have been the source of or contributed to the problem.

I think this might be part of your problem. I just had a problem with the alk in one of my tanks and all my corals turned brown. They are coming back but it is taking some time.
I do think your fish load could be a problem. When I was running my other tank with fish I had great color then when I transfered just my fish over to my other tank my corals slowly faded in color they did not turn brown but the color faded out over a few weeks. I was not feeding at all at that time as there were no fish.

[simplycoral]

Originally Posted by Ron99

Tank has been running since last May, was set up with established and cycled rock from other tanks so there was no cycle to speak of. Lighting runs 10.5 hours each day. Some corals have been in there since last may much of the others have been in 5 or 6 months. Salinity is stable as I run an ATO. Other parameters seem a fairly stable as well although I don't check every day. But they are similar when I do test. Flow is about 300gph through the sump and I have an MP40 running about 2/3 full power which gives plenty of water movement. Test kits are a mix of Elos and API. I have also tried some hagen test kits too for phosphate and ammonia/nitrate/nitrite. But all read zero or very close to it when I test so I don't think I have a major nutrient issue as I can't see getting false negatives all the time. I'm also not seeing any algae blooms; just the normal dusting on the glass that needs to be cleaned every few days.

I didn't think a cup of skimate per week was that much. I see others pulling that much in a few days.

How old was the rock? There could be a lot of nutrients bound up in the rockwork which is now being released? I don't believe any of the test kits any more most are unable to accurately read low levels and the problem with nutrients is they are often absorbed by the corals and other elements very quickly... Your SPS & Cheato are feeding on the nutrients.

I fill my Skimmer cup every other day with a dark skimate.

Simon