Backyard Aquaponics
A place to discuss aquaponics

Tilapia in RAS. Zero ammonia, PH around 7.8. If I stop feeding for a day or two, the nitrites will drop to zero. I don't want to not feed, as I'm trying to get max, or at least very good growth from fish. I added some additional Bio bags to mbbr filter as well as some additional netting to shade cloth/netting filter. Fish seem fine, and are eating and growing well. PH is down almost .5 in filter tanks, so they are certainly working. I know tilapia can tolerate higher nitrites then .5, but will keeping them in that level for a long time stress them or cause any problems? Thanks!

As long as you keep the salinity at 1-2ppt, it should mitigate the effects of nitrite poisoning.

Thanks Charlie...that's about where I'm at...2ppt.

From what I've read, the nitrate reading in the RAS show up from the water not having enough suspension time with the media. So it's rushing past the media too fast for all the nitrites to be converted.

But like Charlie says, it'll be fine as long as you're salted. Keep an eye on it for when the fish (feeding) volume increases.