Backyard Aquaponics
A place to discuss aquaponics

I have a relatively new system that is around 3 months.

System consists of 2 x 500 litre grow beds and a 2000 litre tank.

Current readings are:
Ph 6.4
Ammonia 0.25
Nitrite 0
Nitrate 0

I started off with only guppies and a couple of silver perch, and the guppies were very healthy for a good while.

The system appeared to have cycled 2 weeks ago when Ammonia levels and Nitrite levels were 0, with Nitrate levels at 40 and added 10 more silver perch from my other system.

However, subsequently several silver perch and many more guppies have died.

The water has turned quite green and gets a lot of open sun.

Would the algae in the water be suffocating the fish? Does the tank need covering?

The silver perch in this system are also far less active than in another system I have where the temperature is far lower and doesnt get direct sunlight.

Thanks.

Have you got any pics of your system (sometimes it helps to spot a problem).

Have you got additional aeration? My first guess is the algae is consuming the O2 and effecting the fish.

Id ramp up air, maybe switch to CF, add 2kg add pool salt and cover the FT.

Thanks!

I have put the pump on to constant flow and will see the results in the morning and added the salt.

Attached are some pictures.

Are they the hot dipped galvanised BYAP stands.... stepped in the fish tank????...

Galvanised zinc is a soft metal.... and with acidic AP water... would probably leach and kill your fish... (as well as seriously shorten the life of the stands)...

They don't look like they're the BYAP stands.. so what are they made of.... and what/are they painted with??

And thats why pics help us understand the full picture.

The stands are made of hot dipped zinc galvanised bar, painted with a rust proof paint called "Rust Guard", and epoxy enamel paint.

Would this paint actually be leaching into the water and making it toxic, and how could I determine whether this is actually the case?

If I did need to cut the legs off, would pavers/bricks be able to sit in the water in order to hold up the stand? Or would they also have some form of chemical leach from them?

So I removed the legs, replaced with old pavers, completely cleaned out the tank and started afresh.

However within hours the water has gone green again, I imagine this run off from the grow beds and will go away in time? The tank is currently covered, and algae has not had time to grow on the side of the tank yet...

Algae is not a bad thing for most fish. All summer long I grow my tilapia out in greenwater. Only thing I do is pump air into it and they do great.

I recently had a major algae bloom and the fish loved it. All 30 SP survived it. The algae has collapsed since I salted, covered and CF. Clear as now and fish still healthy.

I'm not an expert, but the main disadvantages of algae in AP are:
1) it's a plant and competes with your veggies for nutrients
2) it can raise ph

3) consumes oxygen

4) Looks terrible

5) can't see your fish to see if they are flashing etc.

6) Cant see any excess solids/uneaten food which may be on the floor

Tank is covered with black pastic but algae is still growing.

Ph: 7
Ammonia, Nitrite and Nitrate: 0

1 dead silver perch this morning...

Still can't get this system right, the other one is flourishing with fish jumping everywhere!