Nitrification in low KH low pH environment?

[defdac]

My biological filter media have been troublesome the last couple of months with great instability (algae, Cyanobacteria and fuzz algae), so I've been reading up on nitrification and found this:

http://www.bioconlabs.com/nitribactfacts.html

I have low KH < 2 and aims for 6.2 to get really good CO2-levels.

"At pH levels below 7.0, Nitrosomonas will grow more slowly and increases in ammonia may become evident. Nitrosomonas growth is inhibited at a pH of 6.5. All nitrification is inhibited if the pH drops to 6.0 or less. Care must be taken to monitor ammonia if the pH begins to drop close to 6.5."

I guess the answer will be it doesn't matter when the plants are fine and soaks upp all ammonia, but it must mean low KH tanks are a bit more jumpy in low pH environments?

 

[Tom Barr]

Re: Nitrification in low KH low pH environment?

I do not think this is a real issue for us, I alos see little difference between high and a low pH tanks, the pH is also artifically lowered using CO2.

Only if you use no KH or .5 etc might you have an issue.

Regards,
Tom Barr

 

[Tom Barr]

Re: Nitrification in low KH low pH environment?

Low O2 levels also show a good reason to do a water change after a large uprooting and tank redo.

Uprooting all the seidment mulm will greastly reduce O2.

"Maximum nitrification rates will exist if dissolved oxygen (DO) levels exceed 80% saturation. Nitrification will not occur if DO concentrations drop to 2.0 mg/l (ppm) or less. Nitrobacter is more strongly affected by low DO than NITROSOMONAS."

So whether it's the break down of the bacteria all over the tank, NO2/NH4 etc or the low O2, is not clear.

Regards,
Tom Barr

 

[jerime]

Its seems I'm developing a habit for bringing old issues up - sorry
What are the effects of lower then 5 PH on the nitrification bacteria, not the one's we thought are active in that process (nitrosomonas and nitrobacter) but the ones we now know are active - do they die at that lower ph and new ones are formed and active, is their rate of operation slowed down or whatever else?

 

[Tom Barr]

I think it remains open to debate and speculation.

In our context, using pH reducing tannins from wood, peat/ADA AS( which is still peat) and CO2 to artifically depress the pH, may have a lot of influence.

Uptake by vigorous plant growth can account for a lot of NH4 uptake from the system, but when that growth is peturbed, or when a large pulse of NH4 is added, it may be hard for the abcteria and plant uptake to respond.

So a lot of focus should be placed on plant growth, health and stability if you ask me.
Likewise, large frequent water changes removes NH4 waste as well as zeolite, so if you wanted to do a control, zeolite would do the trick and remove the NH4 and as far as I know, the zeolite is not affected that much by the pH.



Regards,
Tom Barr