Aquaponic Gardening

A Community and Forum For Aquaponic Gardeners

Hello all,


I'm a newbie, very new to everything.  The idea of aquaponic fascinated me after 6 months of intense research on urban farming.  My plan is to master this, so I can turn it into a business, since I'm tired of working as an attorney, and wants to become a farmer (everyone think I'm nuts, but I dont have any passion practicing real estate law anymore). So over a month now, I finally set up a 275 gallon IBC system to test out Aquaponic.  To my amazement it's not as easy as I thought it would be.


I got 12 channel catfishs and about 20 bluegills from going fishing for them. Filled my growbed with 100 liters of generic medium, similar to hydroton. A week later all the fishes died.  Then I just found out, after more research to get a testing kit at Petco to test out the pH level, temps, Nitrates, Nitrites and Ammonia.  Got that yesterday and performed the tests.  pH is at 7.6, temp is always around 76 degrees, nitrates and nitrites and ammonia are in good standing.  Also yesterday I put 20 gold fish in.  Today, after work I test out the water again, everything is still the same but pH rises to 8.0, and 5 of the gold fish died.  I figured probably the reason is because of the pH level is too high.  I really want my pH level to be between 6.5 and 7.  What can I do to accomplish that?  I got some pH Down and Up droplets but for my tank size, I dont think it's practical with the small bottle.  Is there a better way to decrease the pH level, meanwhile it does not harm my fish and my vegetables.


Your expertise is greatly appreciated.





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Thanks Chris. I thought it'll be better with sunlight. Guess not huh. 


Well here's my stats now, this means Im close to be done with cycling right?


pH: 7.8

Ammonia: .5

Nitrite: 5.0

Nitrate: 20.0


Correct me if I'm wrong, but according to my understanding, Nitrate suppose to be high and Ammonia, and Nitrate suppose to be low, right?

Right you want ammonia and nitrite to be 0 and nitrate anywhere between 0 and 60-80


You still have a bit to go though as the nitrite are still dangerously high.  1 ppt of salt dissolved into the system water can help protect the fish from nitrite a bit though.  1 ppt would be 1 kg of salt (cheap solar pool or water softener salt is usually pretty cheap for a big bag) in 1000 liters of water.

TC, if I added a tsp of Muratric acid to the water tank, will this reduce Nitrite?

No, muratic acid changes pH but won't directly affect the Nitrite level. 


You will have to wait for the bacteria to bring the nitrite down, reduce feeding, or do a water change if you want to see a lower nitrite level. 


I also don't recommend adding acid directly to an aquaponic system.  If you feel the need to use acid to change the pH of a system, I recommend adjusting the pH of the top up water and letting it stabilize before using the adjusted top up water in the system.  Adding acid directly to an aquaponic system can often cause sudden changes in system pH that are way too much for the comfort of fish, plants, and bacteria. 


I don't think your system needs pH adjustment at this point in time, the pH will probably come down soon as the bacteria finish cycling up and the nitrites come down.

Today is Tuesday, and I tested every day.  My Nitrite is still at 5.0, Ammonia is at 5.0, pH did dropped down to 7.6, and Nitrate is right around 20.0.


Should I do a water change to lower my Nitrate down?  Some of my plants started to have yellow leaves, but my fishes are doing fine, my water is very very clear.

Nitrates are not dangerous to fish until they are way off the chart.


The ammonia and nitrite levels worry me. STOP FEEDING

What sort of test kit are you using?

I wouldn't worry too much about the plants until after you get the system cycled up.  You may need to do a water change to bring the ammonia and nitrite levels down to keep from killing fish.


If your ammonia or nitrite levels are much over .25 you should reduce feed and if they get much over .5 I would say stop feeding. 

You may have too many fish for the grow bed. Check your ratio of fish to grow bed and see if your calculations are correct. Volumes are the key to a balanced system. You may be fish heavy.
Kou I diddo TC on stop feeding till your ammonia goes to .5 or less. Do not adjust ph when ammonia levels are high your ph test kit will give false readings. I know we told you to cover your fish tank but due to high nitrites I would let sunlight into the tank to help lower the nitrite level. Nitrites dont like direct sunlight and exposing them to it will help drop them. Your nitrates should continue to climb and ammonia drop if your system is functioning or cycled properly. Your close just keep monitoring every day. Your ammonia level is spooky high but koi are tough. If your ammonia doesnt drop quickly let us know. You might need to do a 50 percent water change.

Kou said:

Today is Tuesday, and I tested every day.  My Nitrite is still at 5.0, Ammonia is at 5.0, pH did dropped down to 7.6, and Nitrate is right around 20.0.


Should I do a water change to lower my Nitrate down?  Some of my plants started to have yellow leaves, but my fishes are doing fine, my water is very very clear.

Hi guys.


Now I'm only feeding my fish once a day.  I'm afraid if I dont feed them, they'll die.  I have 40 Kois and Tilapias but they're only 2-3 inches.  I know once they got bigger, I will need to add another tank.I have about 13 plants on top.  My system runs 24/7.


My readings today are:


Ammonia: .25

Nitrate: 160

pH: 7

Nitrite: 5.0

Temps: Around 70 all the time.


Please suggest of what I should do to lower the Nitrite. (Will a water change, lower my Nitrate level). The system is outdoor in an open area, expose to everything. During the past few weeks, we've been having alot of rains and unpredictable temperature swings.  I'm planning to built a 12X16 green house around it, this weekend to ensure it's not expose to this crazy weather.


The test kit, I'm using is from Petco & Fish store, it's from API.

Wild swings in the readings. On Tuesday you had 5.0 on ammonia today you have .25 that is a great change. Did you change out water?

Hi Kou,

The fish can go for two weeks without feeding. Please do not feed!! Your nitrites are too high so a 50% water change as soon as possible. You're still cycling, and from your temperatures shouldn't be more than one week left, so have some patience but no more feed for now. You can test every other day until you get zero nitrites before you start feeding.

Chris, I have not changed the water. But Tuesday night it rain for a couple hours.


Harold, so you recommend do a half water change, in order to lower my Nitrite level?  But will this effect the system, and probably prolong it?


Typically a fish cyling system with plants, takes how long for the cycle to complete?   Man, this is harder than law school....hahahahha

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