Backyard Aquaponics
A place to discuss aquaponics

Nutrient is only short for the plants if Nitrate is 0 ppm AND the plants are showing signs of nitrogen deficiency. Then you can add some other source of ammonia (very carefully so as not to cause a spike that would harm your fish) to up the nutrients until you can get some more fish. Feeding high quality, high protein feed can also make a difference in the nutrients available for the plants.

TC, Thanks for the advice. Didn't know that one can still use ammonia to increase the nitrate level at this stage. Hope I don't have to do so as fishes may suffer. However I have no idea how soon the plants will consume the nitrate in my system which is around 20.

I generally say don't add ammonia to a system with fish in it. Some people do when needed but they make sure it is really needed and the bio-filter can handle it so as not to hurt their fish.

I've got a system that has been operating with about 5 ppm of nitrate long term and it's doing very well and I like it like that.

TC, thanks for sharing. Just went to the fish farm today and bought 30 over 10-cm kois. As my quarantine tank is not ready, I just put the bag (with oxygen inside) in the FT for about 30 min to recon the temperature and then add the fish directly. Am worrying if the fishes could carry any disease. Hope not. With the added fishes, I am looking forward to seeing the full-blown of the plants. cheers.

A few updates.

PH has dropped to around 7.4~7.6. Fishes are doing very well. Plants in the gravel bed are growing well but not in the raft beds as some problems were experienced. e.g.

- did not correctly put the seeds in the foam cube resulting in low germination rate and poor quality seedlings;
- insufficient DO resulting in poor plant growth as I just floated the poly board on the water surface and no aeration was arranged underneath. Have since fixed the height of the board and am using flood & drain style now as don't want to use an air pump for fear of the noise;
- used foam cube as media in the bottom of the black cups resulting in insufficient anchorage for the seedlings and thus poor growth. Am using expanded clay as the media now.

With above trial and error and the improvements, I am looking forward to a better growth situation in the raft beds.

A glimpse of the growbeds now. System has been running well since last update except that the red lettuces do not really turn red. Don't know if this is the lack of sunlight or nutrient or both. Cheers & happy AP to all.

The red lettuces definitely need bright sun for the best color.

Thanks TC. So sunlight is the reason. It's winter now here and my balcony gets only about 3 hours weak sunlight in the morning provided that it's a clear day. I notice that the leaf of the lettuces is also thin and fragile. Seems nothing I can do about the sunlight unless I use growlight as compensation. Need to do a feasibility study first.