Toxic Algae

[BryanC]

I have an established, very stable planted tank (120 gal). PH is controlled automatically @ 6.9, very low Nitrate, essentially o ppm Nitirite, Ammonia, Copper etc. Very high water quality. I have repeatedly attempted to add Amano and Cherry shrimp for alagae control with 100% death rate within 24 hrs. Here is what happens: 1) I carefully drip in shrimp for 2 hrs or so, 2) Add them gently to tank 3) Shrimp are active and immediately begin feeding on algae. 4) After several hours, shrimp stop moving and quickly die. I have exaustively eliminated any water quality issues. It appears that something they are feeding on is toxic. I do not appear to have any blue green algae (cyanobacteria). Shrimp are appear to be feeding on normal green algae on plants and glass walls. I'm totally baffled and a bit frustrated as I would really like to have some Amanos to help with algae. Any thoughts?

[gurglegurgle]

the first thing that comes to mind is that copper may have been used in the tank previously

[gurglegurgle]

and you mention that you have algae problems. Are you/have you dose anything that may contain copper? Fertilizers?

[imma24]

PH is controlled automatically @ 6.9, very low Nitrate, essentially o ppm Nitirite, Ammonia, Copper etc.

I don't know if this would matter or not, but what are you controlling your pH with? Or am I reading this wrong?

[Lady Hobbs]

Are you using Excel?

[dmagerl]

PH controller implies CO2 injection to me. In my experience, thats almost instant death to shrimp.

[Cliff]

In addition to the questions and comments already made, I would also suggest larger water changes to help lower your nutrients in the water

If you are having a bad algae problem then you can not trust your nitrate test results to be accurate. Algae will consume nitrates and phosphates almost instantly, too fast for you to get a true sample for testing.