red algae

[bferg]

i am having a problem with red algae in my 20 gallon saltwater fish tank. i use the Eclipse system and the full spectrum lights are on 16 hours a day. there are 8 fish in the tank and the longest is 3 iches. we do a 25% water change every 6 weeks. the tank has been set up for 3 months and the water is tested every two weeks for nitrites, ph, salinity, ammonia and temp. the tests are always within the normal limits. so far we have tried changing the lights and the times they are on, phos-zorb, putting and algae blenny and snails into the tank. nothing has worked, after removing as much of the algae as possible it comes back as bad as ever in 3 or 4 days. it's becoming a real chore. every pet store i have asked has me given me different answers. its difficult to get information on saltwater tanks. i would really appreciate your help.

 

[sixth man]

too many fish equals too much nutrients in the tank. what are you thinking leaving the lights on for 16 HOURS. that is a bit excessive. keep them on for 8-10 hours. fish don't need the light or probably want it on. if you had corals you could make it 10-12, but just fish, that's nuts. you are way overstocked and there isn't nearly enough filtration in that tank to take care of all the garbage that those fish produce. you definately need some scavengers to clean up after the fish mess. a 20 gallon should have about five inches of fish maximum. there is way too many nutrients in your tank being produced by the fish waste, fish food, death, fish slime, etc. you should probably change your water 15% every three weeks instead of your current rate. that tank is probably real dirty and has way too much waste in it. a protein skimmer would probably help too. just some thoughts

 

[hairtriggered]

Is your tank in direct sunlight? That can affect a more marked algae growth than leaving tank lights on too much. Are you using a pH buffer? Check the label; Some are heavy on the phosphate and that feeds the algae. If your test levels are okay, that would be my guess. I believe there are tablets on the market that nutralize the phosphates and reduce the algea growth dramatically but you want to try to figure out the cause before rushing in with the chemicals.

 

[etpuffer]