Backyard Aquaponics
A place to discuss aquaponics

My System is a 1000lt fish tank with one standard grow bed & one half that size almost 3years old , in the last couple of months I have been getting high nitrate readings continuously, I have changed about 50% of the water at least 3 times replacing with scheme water. I have lost about 12 nice native goldfish, only have about10 left. I am reluctant to get more fish until the water is right. I have had good growth from the plants in the system, so wonder what the best plan is to get the nitrate down from 160 plus.

Hi Facetor

I'm still new so can't comment too much, but you'll probably get a better response if you also post some other info like
- temperature
- ammonia, nitrites, and ph levels
- what type of system (ie chop etc)
- what plants you currently have
- what media you use
- how much food you normally feed fish

This will help people give you advice!

Oh and pics, pics always help haha ;p

Hi Bcasey 2703, Thanks for the reply, I am not feeding the fish at all at present to try & help the Nitrate to come down. The temp is about 18deg the Ammonia is 0.25ppm, P.H 7.6, Nitrite 0.0 ppm. The plants I have in at present are Chilli /4, Capcicum /4, Mint/ 1, Rocket Lettuce /6, Other lettuce /6 & Spring Onions about 50.

I had high nitrates for the last three weeks. I put in two tomatoes. A strawberry. A cucumber. A chilli. And a capsicum.
Levels were 40/80ppm. Did a test yesterday and there back down to 10ppm. I also add 100ltrs of aquarium water each week to my IBC. Grow beds. The fish tank levels were. A0.25 nitrite 0.25 nitrate 80/100. Yes I should clean it more often. My system is almost six months old. I am growing 3 Sliver Perch and 5 Barramundi. 1300ltrs

Nitrates aren't usually much of a worry to be honest.
They'd have to be off the charts in a big way to be a problem for the fish and I can't recall anyone having any real problems with high nitrates.
Ammonia and nitrites are another story though of course.
Mind you, the change of readings in a 3 year old system is interesting and it's worth looking into what's happening.
I wonder if the beds have a lot of solids in them after that much time?
(I'm also wondering what a native goldfish is?)

High Bodgy, I have had a good look down into the media & there is not much there in the way of solids I have a bit of Algea but not enough to cause any bed readings. The native Goldfish is just a dark grey fish which does turn to a gold colour over time some of them don't change at all. They probably will grow to about 2-3 klg over time.