Strange new behavior and some algae...

[luconi]

I have a Biocube 29, and in it I have some soft corals (zoas, a ricordea, and some green star polyps), a sixline wrasse, a clownfish, and a sally lightfoot. For a little while I slacked on water changes and the zoas seemed to get slightly smaller, so I did about a 50% water change over a period of 3 days (I also added the Chemiclean brand red slime remover to get rid of a little that was growing on a rock). Right now it appears as though more green hair algae (which I had nearly none of) is growing AFTER the water changes than before, and the red slime algae just came back. It has probably been about a week since the 50% water change. Is there any reason for this algae growth? The nitrates measured out to be only about 5-10 (the same or less than the amount before the water change. I do not use tap water for water changes, but buy premixed saltwater that is made with RO/DI water. (I'm using activated carbon by the way, and during water changes I siphon the substrate that is not covered with rocks).

Also, there has been odd behavior in my two fish. The things I explained that I did earlier, like the 50% water change over a period of 3 days and using the red slime remover, I have done before the strange behavior and the fish behaved normally. Their strange behavior is that they seem afraid to come out of the rockwork. First, it was just the clownfish who seemed afraid, but now it is the sixline also. Strangely, neither will come out boldly during feeding time, and this is VERY abnormal for them. The sixline seems to come out when it is NOT feeding time, but hides when I try to feed them the mysis shrimp. Are there any reasons for this quick and odd change in behavior??

Thanks in advance for answers!!

[chimmike]

your water source was not 0 TDS water, introduced unwanted nutrients (probably phosphates) into the water, feeding the algae. Your readings are low because the algae is sucking them out of the water.

Stop using the red slime remover and find a 0 TDS ro source for water, then just scrub the hair algae off with a toothbrush and remove it. It won't come back.

[luconi]

I wouldn't say that there is enough algae to do suck it out of the water like that. There is only a very small tiny layer on the rocks. Probably only about 1/16 of an inch. It's just that I had basically no algae other than that on the powerhead previously. And this is not a new tank and I've been using the water from the same location for a while for water changes and haven't had problems except when first starting up.

And any ideas on the behavior changes?

Thanks for the answer!

[luconi]

Any ideas?