Do bacteria use Alk as a carbon source?

[jamesamantha]

Hello,

I have been having trouble keeping my Alk above 7. I read a thread that suggested bacteria can use Alk as a carbon source. I do have a bacterial film that is growing on my liverock. Looks like short hair algae but it isn't algae, kind of clearish brown, furrry stuff that you can toothbrush off but it comes back in a day. pH hovers around 8.1 with a calibrated meter.

So am I feeding this bacteria with the Alk I am added every day to the tank? I use a two-part via periastalic pumps, about 10ml a day right now. I have been adding an additional 3/4 tsp of soda ash (dissolved in RO) per day to try to get the Alk up.

Thanks,

James

 

[bertoni]

Photosynthetic organisms can use alkalinity as a carbon source. There's not much you can do about that. They generally seem to be able to use dissolved carbon dioxide as well.

 

[jamesamantha]

That is interesting. I guess I will quit trying to drive alk about 7. I was trying to get alk higher since my pH runs on the low side.

Thanks for the input. I really do appreciate it.

James