Backyard Aquaponics
A place to discuss aquaponics

Started cycling the AP system with 2 lettuce and seedlings in the system (no fish). Here is my water sample
ph - 8.4
ammonia - 0.25
Nitrite - 0.25
Nitrate - 20

What should I be looking for to start adding fish? Anything else I should do?

Have you added anything to the system? What have your levels been? You want to wait until your ammonia and nitrites are starting to drop down, then you know the bacteria have populated.

Hey great job. I have been cycling for 3 weeks and not as far as you. Keep it up!

Thank you Keegun. Check this after and got some sprouts from my seeds (kind of surprised)

Earthbound, I haven't added anything, although I was told Ph is too high (lemon would be the natural way to bring that down I was told). So i want my ammonia and nitrites to be at 0 before I add fish?

My first sample was about 2 weeks ago and was Ph 7.8, Ammonia 0.25, Nitrites 8, Nitrates 20 ppm

don't add fish. you havent cycled.
you need to resolve your system chemistry.

(a) get some water same source as your fish tank and test it after being in a bucket for 24 hours.

high nitrates early on could indicate chloramine. Complete all tests on the bucket water - pH etc.
see bottom or do a search around here - common issue in US.

(b) the test of whether the system is ready is that you can add a liquid fertiliser see the ammonia go up and then drop down to below 0.25 (ideally 0), without seeing any nitrite levels above 0.25 (ideally 0).

(c) you need to see the nitrates dropping -add some more plants if necessary - the nitrates are probably not from cycling based on your numbers and information presented.


if you want to get your pH down then get a bucket of water and add hydrochloric acid (HCL).
Then once stable add it to your system. You can do this easier while you don't have fish.

Vitamin C is one option for breaking down chloramines.
Try this thread > viewtopic.php?f=18&t=29256&p=560306&hilit=chloramine#p560306

Starting to get some algae build up on the sides of the fish tank (no fish yet) should that be concerning?

par for the course. You have nutrients and not enough established plants to make use of them.
Many new systems experience an algal bloom.

you don't have fish, so that is bonus (else you need lots of air as algae uses it up)

Run the system 24/7 and if you like add some air to circulate the tank.
Make sure you have some decent plants in the system.
Let it run its course.

Alage, particularly pea soup or strand type, is a sign your system does not have the capacity to use the nutrients it produces. This is different to the dark green type algae/bacteria that coats the fish tank and is present in all systems even when the water is clear.

Go with the flow and don't try to add any aquarium/pond products.
The algae will ultimately end up in the grow beds as fertilizer anyway.