Backyard Aquaponics
A place to discuss aquaponics

Hi all got a AP system a few months old been cycling for over two months had some spikes in the ammonia, nitrites and most recently the nitrates

I started with fishless cycling

Ph 6.8
amm 0
nitrites 0
nitrates 0

after first round of ammonia dosing to 4ppm amm spiked over what the test kit could read water change and got it under control then i dosed again to 4ppm the amm drop and the nitrites spiked over the readable zone of the test kit another water change and got that under control i then dose to 1 ppm amm and in a couple days amm and nitirites began to drop nitrates started to rise it stayed around 40-80ppm for a week then it just spike to over 160 ppm i stopped dosing and for a week it stayed at over 160 ppm so i did another water change and dose to 1ppm amm and 24hrs later no trace of amm or nitrite dose another 1ppm amm 24hrs later no traces of amm or nitrites during that last 2 dosing my nitrates 5ppm so I think I'm cycled so i added fish Saturday and all are doing well

ph 6.8 with buffer
amm 0
nitrite 0
nitrate 0

I had 2 problem during the cycling period my ph spiked over 7-8 and came down with the o2 changes
but when i got the nitrate spike it dropped well below 6 so i added crush egg in a net bag to the out of the ft to the sump that seems to help the ph swings

my biggest problem is in the 3 mnths my plants in the 2 bed are not growing well the tomatoes, bak choy, celery and lettuce never grew i only saw culantro and chives growing

anyone got an idea of what could be happening
I will post some pics....

here are some pics

the chives and culantro are from cuttings i just stick in about 3wks ago they are doing kind of ok!

Well here's my thinking on this - You've been dosing with ammonia and while that gives you nitrates that your plants can use and that help get the bacteria going, it doesn't give other nutrients to help you grow the plants. Some media might provide these but apparently yours isn't. Between those two things, how long it took for the system to cycle and the evidence in the pictures, I'd say your plants are having troubles with nutrient deficiencies. Hopefully you're using a good fish feed and now that you have fish the problem should lessen. Having said that I'd be tempted to sprinkle some Blood and Bone (50g per 100 L) or equivalent organic fertilizer into the grow bed to help the plants get going. The fertilizer doesn't need much nitrogen because that you do have so it can either have low nitrogen or slow release nitrogen like the Blood and Bone.

Thanks scotty435

The system about a month to cycle but because I didn't fully understand the cycling process i had to water change due to overdosing amm i have to be honest all the growth happened within the first cycle attempt and after the first water change the plant just stalled ooh just remember I got 40 tilapia's 4-5" are those enough to support my 2 growbeds?

More than enough, you're probably overstocked. Tilapia might be able to handle this but watch the ammonia and nitrite levels.