The Shrimp Dilemma

[Oto]

Hello. I have for some time now had problems keeping shrimp alive. I'm not sure exactly what it is but it seems that something does not want me to keep shrimp!

I have a 55g planted tank, 4x54W lighting, Pressurized CO2 (1 BPS), an Eheim 2215 and an Eheim 2236.

I currently have ~30 RCS in there with a handful of Otos. Every once in a while though, I see shrimp just fall over and die. There's really no explanation for it! I've kept Amanos in the past with the same result; they all die.

Water parameters read:
PH: ~7.5
Ammonia: 0
Nitrites: 0
Nitrates: ~20 (dosing ferts)
KH: 6
GH: 6
Copper: 0

I use Prime.

I really don't see anything wrong. I acclimated my shrimp for over 24 hours and they seemed to do great. Was it perhaps bad stock?

I would think that the two filters would be enough so I didn't see it being a water quality issue.

[Mustafa]

If all the shrimp youe ever buy just up and die, then it must obviously be your tank. In this case I immediately saw your CO2 and Nitrate levels as the possible culprits (and probably just fertilizers in general). Nitrates of 20+ are way too high for shrimp. Nitrates should be under 5 and, if possible, 0. Shrimp need lots of oxygen so CO2 is really counterproductive in the shrimp hobby. Yes, I know..there are people keeping shrimp and using CO2...but that never goes well in the long run.