Backyard Aquaponics
A place to discuss aquaponics

I have a nitrite problem in my fish tank. It has stayed at around .5 since I started the system, and I can't seem to get rid of it. The fish have been in the tank for about 10 weeks now, and I have lost about 6 fish in the last week or so - I presume from nitrite toxicity. The sick fish are very slow, and don't swim too well. They haven't actually died, but I gave any sick looking ones to the dog.

My thoughts are either:
- The turtle, and couple of yabbies in the sump are the problem, as the water is not filtered from the sump to the fish tank (I have removed the turtle, and will clean out the sump totally tonight).
- Not enough filtration. There have always been quite a lot of suspended solids in the water, and alot of crap in certain spots where the fish hang out at the bottom of the tank. I have put in a 4000l/hr pump with the sponge in it constantly curculating the water - there aren't many suspended solids now.

Ammonia has always been 0. I did a 2/3 water change the other day, and it didn't chenge the nitrite reading at all? I do have a big pump, and more grow beds nearly ready to go - they will be up and running definately this weekend. So maybe just more filtration will fix it, but I really need this problem sorted asap, as it is getting to my baby's!

Please, any help or suggestions would be appreciated Cheers

Add 1kg of salt per 1000 liters of water, if you have not already. This will stop the nitrite from being so toxic.

Thanks OBO, I haven't yet done that - I am thinking I will have to though. But I really want a solution to get rid of the nitrite problem? What do you reckon it is???

Salt.

The nitrite converting bacteria take a little longer to establish. My larger system has had high nitrite for over a month before it started to drop. Time and enough GB media. Also the amount of water getting turned over.

Thanks guys. I will salt tonight, and be patient

+1 the salt for fish health. Increase the O2 levels as much as you can for the bacteria. Water changes will not help at that level, and might actually slow things down.

From what I have found, a spike in one or other of the 3 elements A,N,N.
would mean a balance is coming, but the system needs to mature and this wont happen if the drivers keep changing.
Salt apparently will negate the damage by nitrite or reduce its influence
is prolly closer.

+1 for sleepe ya beat me

Thanks heaps guys. There is heaps of oxygen in the system. What is the best salt to use then???

sea/rock salt
bulk from the pool shop, just ID it first to be sure

Calcium chloride, but its harder to get hold of; what C1 said.
Whats the temps and ph?

Cheers

Temp 26, PH 7.2

No problems there then just have to watch out for ich if the're stressed.

Bunnings is running a special on Sunray seasalt (pool salt)... 25kg bag for $5.92 ...