Vodka/Vinegar dosing affecting Alkalinity

[AmherstReef]

So a few months back when I started dosing a Vodka /Vinegar mix , my Alk kept rising up to around 11 dkh so I cut back on my Alk dosing to compensate.

Due to a worsening cyano problem I have to cut back my Vodka/Vinegar by 50% and subsequently my Alk has dropped and I am having to increase my Alk dosing.

Never really though one affected the other, but then again maybe I missed something in Toms great thread.

 

[jeremyjoslin]

I've seen relationship mentioned as well, but don't understand it. I'd be interested to hear a rationale as well.

 

[tmz]

Acetate is generated from acetic acid (vinegar or ethanol which oxidizes to acetic acid in water ).
Acetate adds to total alkalinity which is what we measure and use as the surrogate measure for carbonate alkalinity.Acetate ultimately coverts to CO2 and OH- which adds carbonate alkalinity but not immediately .

I don't think the amounts of acetate we deal with during the transition to CO2 and hydoxide skews away from the usual 96.5% carbonate alkalinity portion of total alkalinity by very much at reef tank ph. Besides the PO4 cosumed by the bacteria and consequent PO4 reduction ( which is also part of total alkalinity ) may offset any skewing that might temporarily occur. In any case keeping your total alk in the mid to upper 7's 8's ,9s dkh should ensure enough carbonate alkalinity for calcifying organisms when dosing moderate amounts of vodka and/or vinegar.

 

[AmherstReef]

...

 

[AmherstReef]

Thanks Tom , it really has not been as issue, I adjusted my Alk dosing to compensate.

While my my nitrates became undetectable, the real issue has been the increase in PO4 and Cyano\Diatoms since I began dosing vodka/vinegar 3 months ago.

I first cut it back by 25%, then 50% with no improvement. Now I am almost back down to zero. I will give it a few weeks with no vodka/vinegar and see if there is an improvement.

I am running GFO which I used to change out about once a month, lately it exhausts within a week.

 

[tmz]

Chris , a nitrogen defieciency may have been limiting the bacteria.