Adding Sulfur to a Dual Chamber Calcium Reactor

[albano1402]

Hello,

I wanted to see if I can add sulfur media into the first chamber of my Super Reef Octopus 5000 Dual Calcium Reactor. I currently top off with Kalkwasser and have the reactor to make up the difference for Ca/Alk demands.

I know that sulfur reactors do not need CO2 to function, but can I leave the CO2 on to help regulate Ca/Alk needs? I have a 120 gal SPS dominant tank.

I want to add the sulfur media to help regulate/reduce Nitrate. I'd like to not lose the functionality of the calcium reactor. Also, I understand that sulfur being acidic will dissolve the calcium media in the second chamber releasing calcium and alkalinity on it's own, but perhaps not at the rate I might need to maintain my Ca/Alk demand. I was curious if the addition of CO2 could be used to increase the rate of Ca/Alk release through the effluent drip.

I currently control my alk reef levels by a PH controller in the first chamber and adjust PH controller CO2 set point control up or down based on my tested Alk results.

 

[Randy Holmes-Farley Verified Community Expert]

I think balancing the flow rate for both processes at the same time will become an issue, but I've not seen results of anyone trying it.

 

[albano1402]

That makes sense. My thought would have been to set the drip rate to account for the Sulfur Drip demand and adjust PH probe up or down based on cal/alk demand changes. If alk dropped in tank, then I would keep drip rate the same and lower the PH probe setting controlling the CO2 to increase alk/ca release in the effluent.

My assumptions is PH in reactor with CO2 off would be greater than or equal to current PH with CO2 on. Alk/Ca is released by the denitrification process and I am dosing Kalk, so I have two steady sources of Alk/Ca.

If after testing Alk rises, (which I suspect will not happen since CA Reactor would have produced a higher Alk/CA output than the denitrification process), then I could cut back Kalk as a means of regulating Alk/Ca.

If after testing Alk drops, then I could add CO2 to reduce the PH in the reactor to increase Alk/Ca release.

Does this logic to trialing something like this, while complicated, seem sound?

The avoidance of adding another reactor to my existing setup makes the above trial appealing if the logic is sound.

I respect Randy's knowledge in the science.

 

[Randy Holmes-Farley Verified Community Expert]

It is a fine thing to try, but I should note the sulfur denitrification actually depletes alk, unlike carbon denitrification which adds it. That's because the CO2 produced by carbon denitrification has no impact on alk, while the sulfuric acid produced from sulfur denitrification does deplete alk.