Backyard Aquaponics
A place to discuss aquaponics

The new(under 3 month) 1 HP regen blower malfunctioned 2 days ago. It was producing air, but at about 50%. We scrambled and managed to keep all fish alive, but the DO in the system went from almost 8.0 to around 4. I stopped feeding while waiting for new blower, which is now online and working better then the original ever did.
Checked the water after about 3 hours of "low air" and the Nitrites were up from under .25 to about 2. Then later Wednesday PM and Thursday AM, they went up to 3-4. Ammonia went from 0 to 1. I had had a steady >.25 on both for over 10 days steady. I had recently cleaned the shade cloth filter(Sunday), but there was no increase after that. Could the increase be just from the lower DO? I haven't checked this AM yet. Also, I have another 20- 1 gallon paint filters that I'm going to make some new smaller bioballs with my plastic scraps. Hopefully, the additional filtration will allow the bacteria to keep my levels very low and I can resume feeding. No feed = no growth.

As you probably already know, it all depends on feed rate, protein mix, # and weight of fish to determine oxygen needed for biofilter and fish. I can pull out the big yellow book to give you the formulas if you need them. Need to know volume of biofilter, amount of media, and generated TAN per day. i am assuming you are using an MBBR...

ebeuerle, Yes, and that was the weird part. I still had O2 going to the mbbr, although it was lower because of blower failure. Everything else was going great, and that was the only variable that I can see. The nitrites are dropping now, and I added some more media to the mmbr, so hopefully no more feed interruptions.

Yes - see page 13 - http://ag.arizona.edu/azaqua/ista/ISTA7/RecircWorkshop/Workshop%20PP%20%20&%20Misc%20Papers%20Adobe%202006/7%20Biofiltration/Nitrification-Biofiltration/Biofiltration-Nitrification%20Design%20Overview.pdf

Thanks Scotty...I guess that answers it. I cleaned/drained the shade cloth filter about 250 gallons, so will add some salt to make up for that amount.