BB slow grow rate

[N_F_S]

Can you help me with my aquarium biological filtration?

My main tank has 480L and two Oase biomaster 850 canister filters(filled with 1l foam, 2l k1 and 3l matrix). With 5 months old, co2 injection, planted with Ada soil and tropicar liquid fertiliser. Current ph 7,2 with co2 off and 6,6 co2 on, kh 4 and gh 6.
I have started with fishless cycle with household amonia and empty tank. In the first time I dose ammonia, I overdosed to 30ppm, nothing happens for 2 weeks. 100% water change and 3ppm dosed, 2 weeks later still 2ppm ammonia and the max nitrite I have seen was 0,20 (never reach the 0,25 of api). I start wondering if my ammonia houseld has a problem and removed the water from the tank. Afterwards add ADA soil and plants and 2 more weeks without fish but with every other day water change, due the ada soil leaches ammonia. In the end of the two weeks, amonia less than 0,25, nitrite after a peak of 0,4, stay less than 0,25.

I started to add fish, and my filter always take care of the ammonia and nitrites from the fish, but never a true 0 ammonia and nitrite, always less than 0,25. But even 4 months later, when dosing tropica nitrogen fertiliser, that adds 0,8 ammonia, takes almost 5 days to get ammonia and nitrite back to less 0,25 again, never saw true 0 and since the beginning, i have cloud water, especially 2 hours after turn the lights on.

I have another tank (my kids tank), 40 L with eheim classic 150 ( small sponge and 1l matrix) , ada soil, planted but no co2. Same tap water.

I have seed some of my matrix from main tank, and one week later, without wc and while soil leaching, got true 0 ammonia and nitrite and always clear water since first day. This tank are far overstocked than main tank and always 0 ammonia and nitrite. I have been out of home for 4 days, and when get home, the kids thank has 6 dead panda corydoras, and even decomposing, true 0 ammonia and nitrite. Same 4 days without food in the main tank, and no true 0, only less than 0,25.

2 weeks ago I have mount an quarentine tank woth 120L and an simple sponge filter drived by 100lh air pump. Right now with 5 angelfish, 1 ram, 1 betta, 1 zebra pleco, 1 ancistrus. After 2 weeks 0 ammonia and 5 nitrite when arrived home(4 days wo wc). Big wc. So even the sponge filter are cicling much faster than my main tank.

 

[seangee]

How many plants do you have? CO2 reduces pH and BB does not thrive in low pH. But if you have a lot of actively growing plants they will use the ammonia and you should have no nitrites.

This tank has a pH < 5.5 BB cannot survive that low (and struggle at 6.6). But I never see ammonia / ammonium or nitrites. FWIW this tank is low tech with no CO2 and plain sand substrate.

 

[N_F_S]

Photo atached. If I don’t dose nitrogen , my tank has no amonia, nitrite or nitrate, and start to grow staghorn algea. If I dose nitrate to stay at 5ppm nitrate, plants consume nitrate and no nitrite or ammonia.

during night, my ph are around 7.
And I have see a lot of discus tanks with ada soil (always buffer to 6,5-6,6), with co2 and less filtration.
When I have tried fishless with dose ammonia, my ph are around 7,6 and nothing happens .

thank

 

[StevenF]

Photo atached. If I don’t dose nitrogen , my tank has no amonia, nitrite or nitrate, and start to grow staghorn algea. If I dose nitrate to stay at 5ppm nitrate, plants consume nitrate and no nitrite or ammonia.

based on everythingI see in my aquarium and have read, Plant prefer ammonia and urea over nitrate. So basically if ammonia is at a safe level for plants, plants will consume ammonia and urea first. and then if necessary then they consume nitrate.

Also algae does best when there is a nutrient deficiency. Zero nitrogen is (Ammonia, Nitrite, or nitrate) is a deficiency. That deficiency is bad for plants but algae doesn't need as much nitrogen and will thrive .

But even 4 months later, when dosing tropica nitrogen fertiliser, that adds 0,8 ammonia, takes almost 5 days to get ammonia and nitrite back to less 0,25 again, never saw true 0 and since the beginning,

Some nitrogen fertilizers contain urea (CO(NH2)2 which will decay to ammonia (if the plants don't consume it first). Other nitrogen fertilizers have ammonia salts such as Ammonia nitrate ( NH4NO3 ) or Ammonia sulfate( (NH2)2SO4 ). Some ammonia test kits will detect ammonia salts while others only detect ammonia

Other nitrogen fertilizer are made from potassium nitrate (KNO3). There is no ammonia in KNO3. That should not register on any good ammonia test kits.

I don't know what is in the bottle of Tropica Nitrogen fertilizer but if it has ammonia salts in it a dose of 5ppm nitrate may also have with it a lot of ammonia which will not show up in a nitrate test. You could try dosing less Tropica nitrogen May be as little as 1/5th of your previous dose. or you could switch to a source of nitrogen that is 100% potassium nitrate.

2 weeks ago I have mount an quarentine tank woth 120L and an simple sponge filter drived by 100lh air pump. Right now with 5 angelfish, 1 ram, 1 betta, 1 zebra pleco, 1 ancistrus. After 2 weeks 0 ammonia and 5 nitrite when arrived home(4 days wo wc). Big wc. So even the sponge filter are cicling much faster than my main tank.

in this tank your heavy fish stocking is producing just a little bit more nitrogen enough then your plants need and as a result it has better water quality.