Backyard Aquaponics
A place to discuss aquaponics

What would be safe nitrate levels, currently have silvers and Barra and the Barra have gone off there food also lost a couple of silvers lately at about 200mm, I've checked my levels and PH 6.8 temp between 25 - 32 and nitrate 20 - 40 is it too high what is the recommended? I am over stocked with fish at the moment so have held off on there food for now.

Cheers in advance

Nitrate levels can top 1000ppm before fish start to have problems.....

Short term exposure to around 450ppm+ can be harmful to many of the commonly grown species, but studies have shown that longer term exposure to levels as low as 150ppm can cause harm.

IMO, if your system runs at 40ppm+ constantly then you should reduce fish numbers, or add more GB... so Nitrates should never really be an issue to fish health.

Ok so I obviously don't need to worry Bout my nitrates at this stage other that adding more plants to my system, I'm still a bit worried why the barra arnt eating though I just fed them and they arnt interested even though the water temp is 29c

You could try rigging up a flooded bed and grow duck weed..
That could give you an adjustable nitrate sink, whilst giving you fish food and worm food
..
.

Is the water very well aerated?... Barra will handle up to 35C water temps, but only if the water is really aerated.

Is the FT floor clean and free of any uneaten food etc?... have you checked the Amm level lately?

Thanks I might try out an extra bed for duck weed.

I have the beds draining into there tanks and an airstone in each 600l tank so I would think that would be enough air?

The

The tanks are defiantly clean nothing on the bottom and no food in there, there may be some build up in the bottom of the RFF as I havnt cleaned that for a while.

Ammonia and nitrites are all ok.

Have since done a part water change and found to be quite a bit of black sludge in the bottom of the RFF that I have cleaned out and now the Barra are feeding again could it have been what what in the bottom of the RFF?

Hi itechnical,
If you have never checked your oxygen levels, It will always be in the back of your mind every time something goes a bit askew, I couldn't get it out of my head when something looked a bit off or strange in the FT,...
oxygen testers can be very very price prohibited but I found one that seems to be ok and gives me peace of mind...
It cost about AU$15.00, has a use by date of 3 yrs and does 50 tests.
O2 profi test. Salifert and its made in Holland. picked it up from a local aquarium shop.
Its fairly technical but its only drops of water into a tube without shaking it...
well worth it, I don't worry about O2 levels anymore.
cheers

Itechnical,
your initial post was on the 17th saying the Barra have gone off their food, on the 24th your Barra were feeding again. I doubt it was the sludge on the bottom that stopped them from eating, maybe co-incidence...
Barramundi do what Barramundi do....I have 220 Silver Perch that don't eat for 2 days each month then gorge themselves.
next time they don't eat, take note of the moon phase.. don't laugh, i'll bet you get a pattern of times of the month they don't eat.