Bacteria and PH

[Reaperpilot2014]

Does anyone know what ph ranges are too high or low for nitrification bacteria to properly establish themselves? I ask because I'm setting up and fishless cycling a new tank with water that comes out at ph 8.4, and it seems like it's taking much longer than usual to get established. I added gravel from another established tank to start the process. The ammonia isn't being converted, and I haven't seen any nitrites at all. The water I use for my other tanks is ph 8.2 and I've had no problem there. I have plenty of experience cycling tanks, and while experimenting with this tank, am looking for an answer to the ph question.

[sevenyearnight]

At 6.5 pH, they start to work less efficiently, anything below 6.0 pH becomes even more difficult for them to establish.

[Reaperpilot2014]

At what point to they start do die?

And how about higher ph ranges like the ones I have? If that same scale applied the other way, then 8.4 would be a bit high, huh. Before they changed our water I never had anything above 7.8 in my life unless I did it deliberately, so this is fairly new for me.

[sevenyearnight]

I don't know if there is too high of a pH though.

[sevenyearnight]

I don't know, marine tanks have high pH, I know that most of that bacteria is different from fw, but I just don't know if there is a too high.

The importance is more on stability, I know the bacteria is sensitive to shifts in SG, and I believe also pH.

[Reaperpilot2014]

Yeah, that makes sense. I wouldn't think the .2 rise in ph would be enough to just kill that gravel, but who knows? I don't exactly drip acclimate my bacteria.

[sevenyearnight]

RTR can give you detailed information on pH and its correlation to bacteria.

[Reaperpilot2014]

That's what I'm hoping for. I don't think it's common knowledge. I found some stuff on the internet about the lower ph ranges, but am most interested in the higher ph ranges that my water is in.

[RTR]

FW nitrification bacteria do grow quite well enough at pH 6.5 and above. Their optimum is likely at and above pH 8.0, but anything over 6.5 is easy enough for our purposes.

The bacteria are not actively killed at pH 6.0 and below, they just do not grow very well in such acid conditions. Carbonate/bicarbonate is an absolute requirement for these bugs. It is not just the pH itself, it is also the lack of alkalinity/carbonate hardness that starves them.

This one of the areas where folks get into a lot of trouble playing with commercial buffers. Tank biochemistry absolutely requires the same buffering system as if found in the wild - that is carbonate/bicarbonate, not phosphate or other buffer.

HTH

[Pufferpunk]

Better yet--just use crushed coral or aragonite substrate to buffer the pH higher--around a steady 8.

[Reaperpilot2014]

Okay, so my 8.2-8.4 ph is "ideal" then. I'm glad I don't live in an area with where I have to worry about low ph.

[sevenyearnight]

Oh, you are lucky!
My KH from the tap is only 8 - 10 ppm, and it's about 6.6 pH.
But it drops down below 6 in the tanks quickly. I have to add sodium bicarbonate to all of my exchange water.

[RTR]

Believe it or not, my KH from the tap is generally 7-9. But my tanks are pretty stable. I understock and do lots of big partials. For BW and SW, I age and pre-cogition with lots of RFUG aragonite. That water may have a good bit to do with why I am nuts for sumps and refugigia. I have lots of tanks, but not really lots of fish.

[Reaperpilot2014]

Isn't that the way go though? I love it when people look at one of my tanks and see the fish I want them to look at.

[sevenyearnight]

Yeah, I think my biggest issue with the low KH and needing to supplement is the addition of C02, I don't need to add very much, but it's been keeping my pH stable since it was dropping from 6.8 to <6.0 very quickly, it's stays at 6.6 to 6.8 now. I know that was months ago, but thanks again RTR. My planted tank is still doing very well