Backyard Aquaponics
A place to discuss aquaponics

PH has dropped to around 7, Ammonia is at 0, but nitrites are creeping up to almost 5 now. Should I do a water change? I'm going to stop feeding for a few feeding and see what it does. I hate to do a major water change on the RAS. Even a 25% would require me to dump 1500 gallons and add 1500 gallons, essentially wasting 3000 gallons of water.

Is this a new system

Have you salted yet chris? Normally you would not do water changes for nitrites and did you purposely drop ph or did it go down by itself?

Up the aeration in your biofilter this will help the nitrification cycle convert the NO2 to NO3. Another option if you are using an MBBR is to temporarily convert it to a trickling filter if you're setup to do that like some have with their RAS setups. I'm not positive that second one will work but I'm pretty sure.

Yes on new system- I added Muriatic acid 2 weeks ago, but couldn't get PH down under 8. Left PH alone and it's drifting down over the last week. I have salted, but only to 1ppt, I'll add another 50lbs today. I have max aeration in mbbf.
Thanks guys!

Coach - here's some calculations that might help.

Strive for a 10:1 Chloride:Nitrite ratio

With a 5ppm Nitrite, that means 50ppm Chloride

50ppm Chloride in 6000 gallons is 2.5lb Chloride

NaCl is 60% Cl.

4.2lb Salt

Someone please check my math......

I was using the link Ryan gave me; http://www.lagunakoi.com/Pond-Salinity-Calculator.html
It says 50 lbs = 1ppt. I added 50 lbs so far, and was wanting to get another 1%. Didn't feed this AM and nitrites went down. I'm very close to cycling. I fed the fish lightly, and will keep monitoring. Hoping to add another 1000 late this week, early next week. Then need to get my breeding tanks in place.

How are your Nitrite values now coachchris? The airflow may be a bit too much in that filter, you're trying to aerate the mix not remove the biofilm.

It was lower today Scotty. Going to check again in a bit...just got in from work and showered. Already headed toward 90 today. Too damn hot for this time of year. Good point about the mbbf. I'll adjust the air down. It may be too much.