Backyard Aquaponics
A place to discuss aquaponics

Hi all. I have recently started a new system and has cycled 2 weeks ago. The system has been running on CF since set up. Once cycled, all parameters were normal but noticed the nitrates were pretty non existent. I've started to increase the feed for fish while keeping an eye on water quality. It has been running without nitrates showing on tests for 2-3 weeks. I understand it could be the plants just eating it all up. I would prefer if I could see some nitrates in the system just to know the plants have plenty of it available for them.
I switched the system to F&D yesterday 15mins on 45mins off in the hope that this may allow the nitrates to establish. I did a test this morning amm-0, nitrates-0 and nitrites are now creeping up but still below 0.25. Is there anything else I can do to help the nitrates increase? Cheers!

Ibc 1000ltr conversion
12 rainbow trout
GB planted

How did you know it had finished cycling? did you see ammonia and nitrite spike up quite a bit? but never nitrate.

I would just keep pumping in food until you start seeing some, then you at least learn your limit/feeding rate required for plants to have enough.

trout will eat 3% of their body weight per day. if your 12 trout at 100g you should be able to feed out 36g of feed per day without waste.

Hi Taktizer

Do your plants look OK? that's the best test of nutrient levels.

With your system still being quite new some added seaweed extract would help things along.

Media beds take a while to mature it might be several months before they are at their full potential.

patience seems to be the key, with system PH playing a big part in plants taking up available minerals Etc.

Cheers B.F.

Hi guys. Thanks for your swift response. Yes gmturner I had all three spike then fall to zero. I guess as the plants grew there nitrate intake increased. Started with seeds and seedlings. Spinach, strawberries, carrots, parsnips, spring onions, tomatoes, lettuce, peppers and egg plant. I've been using maxi crop and adding a cap full once a week for the past few weeks. I've even added EDDHA chelated iron but just a small tsp which has given the water a pinkish tint but it's still clear and can still see the fish. Some slight yellowing on plants here and there but nothing too major. Do you think switching from CF to F&D could change the balance of the water. There has been a very slight increase in nitrite like I mentioned before but not sure if that was due to the switch to F&D or the increase of feed to the fish or even both.

Cheers!

maybe 15mins of contact per hour is not enough time for the bacteria to do their thing, i dont know.

alot of peoples systems read 0-0-0, so id say you have nothing to worry about unless you have stunted growth or visible deficiencies. Although I think much the same as you, id like to see at least a reading of nitrate so that i know the plants have enough and arent scrounging for it.

Thanks for your help guys, its much appreciated. I was also thinking about switching the F&D to 30/30 setting to see if that would make a difference. Maybe my system isn't mature enough to run a 15 on 45 off sequence. If there's anything else you guys have in mind that may help please let me know.

Cheers!