algae scrubbers and alkalinity

[rwb500]

Hello to the resident experts in my favorite subforum.

Lots of people on the algae scrubber boards say that algae scrubbers can reduce alkalinity. I'm just not seeing how this is possible. As far as I can tell, Randy said it best, in 2004:

Noncalcifying algae do not take up alkalinity, so there is no chance of a calcium/alkalinity balance for that reason. They may take up bicarbonate as a carbon source, but they will otherwise release the alkalinity back to the water (by also taking up H+ or pumping out OH-). There is no sink for alkalinity in noncalcerous tissue.

Randy, is this correct? or has your thinking changed in the last 9 years?

others please feel free to chime in. When he gets here, I expect randy will confirm this so I can put the matter to bed.


there is an awful lot of misinformation regarding algae scrubbers out there. the scene is dominated by like 3 or 4 guys who could all use a chemistry lesson. check out this gem:

"Apparently, co2 hydration into carbonic acid takes 23 seconds. Therefore any contact by co2 at the waters surface less than 23 seconds should not be able to deliver co2 to the water column."

to anyone who remembers high school chemistry, this is nonsense.

 

[bertoni]

I don't see any way that an algal scrubber is going to remove enough alkalinity to be measurable.

 

[rwb500]

that's what I figured, i asked the same question at the algae scrubber forum and the guys basically had nothing to say.