nitrifying bacteria at low pH

[the_deeb]

I've come across a few websites that state that Nitrosomonas growth is inhibted below pH 6.5 and that all nitrification stops if the pH drops to 6.0. I'm wondering if this is the problem with my aquarium - the pH is 6.0 or lower and I'm seeing ammonia spikes despite having established filters, a relatively small bioload and light feeding.

I think I'm going to buy a KH test kit and add some crushed coral to my filters to try to raise the pH.

My question, is what do discus breeders (or other people who use low pH setups) do? I can't imagine there are constant ammonia problems in discus aquariums.

 

[soggydrysuit3]

I have exactly the same problem with one of my tanks. Have to add buffer to keep the pH up. Suspect pH crashes from low hardness water are just as dangerous even to softwater fish.

Have heard the same re nitrifying bacteria at low pH.

Would appreciate any help also!

 

[IKeepPacu]

maybe this is why discus breeders do daily water changes without fail?? just a guess.

 

[ShadowBass]

My question, is what do discus breeders (or other people who use low pH setups) do? I can't imagine there are constant ammonia problems in discus aquariums.

I really doubt there are many breeders that breed below 6.0 pH. The main thing in breeding discus is soft water, not necessarily low pH.

Though if people ARE breeding below 6.0, I'd guess they keep ammonia low by water changes, and also ammonia is less toxic the lower the pH. This is also why you want to lower your ammonia significantly BEFORE raising the pH.

You need to first figure out why your pH is dropping so low. My guess would be poor buffering (kH), and if you are overstocked that will add to the problem, so monitor your nitrates and keep them as low as possible, or lower your stocking level to relieve that issue.
Crushed coral isn't going to noticably raise your pH if your pH is already low. It will only buffer your water to keep your current pH from dropping.
If you have absolutely no buffering in your water crushed coral is going to do very little if anything. You may have to add baking soda or something to buffer your water. You'll then want to monitor your waters kH and do water changes and add buffering accordingly.
Crushed coral will help you out if you've already fixed the buffering issue with the water you're adding to the tank.

Best thing if you actually want to raise pH would be to do so not in the tank, but before the water is added to the tank. You'll need to raise the pH and then add buffering or else the pH will just drop right back off. Trying to mess with the water in the tank itself is going to be tricky and will also stress your fish.

What is your water's pH before you put it into the tank?

 

[the_deeb]

The water out of my tap is up around 7.2. I'm not really sure why the pH in my tank is so much lower. All I really want to do is get my tank up closer to the pH out of the tap. I started an earlier thread about it and didn't get any useful replies.

My stocking load is currently pretty light (since I've lost a lot of fish recently due to the aforementioned ammonia issues). 4 juvie geophagus in a 100g aquarium. So I doubt they're producing enough CO2 to really cause a big problem. The tank has also been getting daily WC recently so excessive waste can't be the issue. I've had far more overstocked tanks and never seen similar problems.

I have a big piece of driftwood in there but it's been there for years and doesn't leach tannins. I'm not sure what's causing the pH difference. Admittedly, I never really paid close attention to the pH since I never had problems with ammonia before.

 

[ShadowBass]

The water out of my tap is up around 7.2. I'm not really sure why the pH in my tank is so much lower. All I really want to do is get my tank up closer to the pH out of the tap. I started an earlier thread about it and didn't get any useful replies.

My stocking load is currently pretty light (since I've lost a lot of fish recently due to the aforementioned ammonia issues). 4 juvie geophagus in a 100g aquarium. So I doubt they're producing enough CO2 to really cause a big problem. The tank has also been getting daily WC recently so excessive waste can't be the issue. I've had far more overstocked tanks and never seen similar problems.

I have a big piece of driftwood in there but it's been there for years and doesn't leach tannins. I'm not sure what's causing the pH difference. Admittedly, I never really paid close attention to the pH since I never had problems with ammonia before.

You have a buffering issue then. If your tap water has a very low kH then the pH will drop just sitting there exposed to air.

You need to test the kH and then add baking soda or something like RO Right to bring it up to a more appropriate level. Like I said, alter the water BEFORE you add it to the tank, and then also run crushed coral in your tank or filters.
If you try to alter the water parameters in the tank itself it will just keep bouncing back and forth.

You can remove the driftwood if you want, but I doubt it's significantly lowering your pH.

Your tapwater may not have previously had any problems and that's why you're just now seeing ammonia issues. Most tapwater doesn't stay consistent. My tap water parameters change depending on time of year.

 

[BushFishRox]

different things can cause ph drop; driftwood, substrate, rocks, ect.

 

[ShadowBass]

different things can cause ph drop; driftwood, substrate, rocks, ect.

None of that stuff is usually a problem in water that has adequate buffering. You can add straight acid, like pH down, to a tank with lots of buffering and it's still not gonna significantly effect the pH.

 

[the_deeb]

Went out and bought a test kit and got some odd results.

Tap water: pH 7.2, KH 40ppm, GH 150ppm

Tank water: pH <6, KH 0ppm!, GH 75ppm

So clearly, lack of buffering appears to be the problem here, as ShadowBass suggested. But what's causing the drop in KH and GH between the tap and tank?

I'm going to take your advice and add crushed coral to my filters. Do you have any idea how much to add?

Also, I do water changes with a python directly into the aquarium. How do you suggest I go about treating the water with baking soda? Should I just add it to the tank during a water change? That seems like it could cause big swings in KH.

 

[itzacraze]

below 6 isnt where u want to be shoot for 6 ... man i wish i had your water minus the ammonia lol