Alk math help

trivan

New member
Generally I'm pretty good at figuring this stuff out, but this one is racking my brain. I'm currently running my CaRx using a MasterFlex pump so I can get a very accurate delivery of effluent to maintain Alk and Calcium. I'm trying to see if I can dial in the ml/min that I would need to set the pump to hold Alk or raise it. I realize this will not be perfect, but close enough is good enough for now.

Here are my measurements:
- In 630 mins - ALK dropped .17 (from 8.01 -> 7.84)
- Effluent is measured at 14.22 (Hanna)
- Effluent is being delivered at 24 ml/min
- tank is approximately 170 gallons

So is it possible to calculate the rate to deliver effluent to maintain Alk (assuming everything else is constant)?
 

tmz

ReefKeeping Mag staff
Premium Member
I never ran mine with a peristaltic pump; I suppose a dosing calculation is possible at a given and constant reactor pH but would require a measure of the actual concentration on alk and calcium in the effluent as a starting point; I think. The concentration of alk and calcium in the effluent is governed by the pH in the reactor; lower equals more dissolution of the calcium carbonate ad vis versa. Balancing the flow through the reactor and the CO2 injection is how most tune in the alk/calcium .
 

trivan

New member
Balancing the flow through the reactor and the CO2 injection is how most tune in the alk/calcium .

Thanks for the input. The reason I got thinking about this was the different calculators out there on how much of a product (eg. part) to be added to raise ALK by x amount. I figured given the fair amount of accuracy that can be dosed via the peristaltic pump, the calculation would be possible. I'm running the pH in the CaRX pretty high at this point of 7.2-7.3, which gives me a effluent of 14.22 dKH.
 
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