Counteracting Calcium Reactor pH?

[penguinexdeus]

Looking for help with keeping pH up as I move to calcium reactor. It's an SPS tank so I'm trying not to allow any huge swings in anything, so stopping all dosing to measure consumption for a full day or two isn't really an option. Been using the reef calculators to help figure out how much of supplements to swap.

Just set up and am still working on getting newly setup calcium reactor tuned. Prior to moving to the calcium reactor I had been dosing 2 part periodically through the day, and Kalk in between those doses and overnight (midnight to 6am). This was keeping my ph at a nice 8.1-8.2 average. House CO2 (have a ppm monitor near tank) is fine and only increases when we're cooking. This time of year I have windows open also and I do have a CO2 scrubber on skimmer. Have a refugium on reverse light schedule. Prior to scrubber/ kalk my ph was usually around 7.8/ 7.9 when it was a very new tank.

After going to the calcium reactor (with secondary chamber) I initially tried to continuously dose and keep the Kalk dosing at night for pH boost. Unfortunately I didn't account for the increase in alkalinity correctly and ended up with a decent upswing in alk overnight. So now I've stopped the reactor at night and allowed the Kalk to dose at night. I also tried adding Kalk into the dosing after my overnight dosing when reactor is starting up and at night after lights out before I start my overnight Kalk. The Kalk seems to be helping pH but definitely not as much as I'd like and it's a struggle to maintain 7.9 pH even during the day. Ideally I'd like to have 8.0 as minimum. The reduction in pH seems to have slowed coral uptake as well which is dropping my consumption and throwing things off also.

Not sure if stopping the calcium reactor periodically for overnight is the right call or if I should dose the Kalk continuously through the day, or dose both continuously. I can't really automate changing effluent rate or co2 throughout day other than on/ off. I am limited in my evaporation rate for dosing kalk to about a gallon a day. my pH upswing had previously been from 10am to 6pm (when lights are ramped up). Looking for suggestions on how to best coordinate my calcium reactor and kalk to help maintain pH, and keep alk swings reasonably minimal. Effluent pH i've been testing with Hanna checker at around 6.8 to 7.0 entering tank.

Additional details:
~85 gal net
alk - trying to keep around 8.2-8.4 as a target.
Ca - 420 to 450 as target
mag - currently 1420, target is around 1400
Kalk dosing with Neptune Dos and Kalk Stirrer (fed from RO top off res)
Calcium Reactor (Geo 510) w/ secondary chamber. ARM media. Current effluent ~25dkH, 10 mL/min, ~6.88 to 7.0 effluent. Chamber pH currently about 6 but I don't trust my pH probe (i calibrated with 7.0 and 10.0 as that's all i had, but 4.0 coming today to hopefully get a better cal) in chamber and with carbondose set to 10 second between bubbles and barely any output pressure (maybe like 5psi) it holds at about 5.9/ 6.0 steady for pH. If i try and set pH higher to like 6.5 the regulator just cycles more than i'd like, so trying to keep it from cycling as per best practice guidance's.

Any help and suggestions appreciated. Thanks

 

[Randy Holmes-Farley]

In general, you would probably want to deliver as much saturated kalkwasser as you can, then adjust the reactor to pick up any excess demand for alkalinity (and calcium) with probably both running 24/7.

 

[penguinexdeus]

In general, you would probably want to deliver as much saturated kalkwasser as you can, then adjust the reactor to pick up any excess demand for alkalinity (and calcium) with probably both running 24/7.

Thanks. I'll aim for this. Should I aim to be consistent with rate of both throughout the 24 hours or should i lean a little heavier into kalk overnight (like a 3/5 night 2/5 day ratio) to help with pH?.

I wont be able to vary the rate through the day of the reactor. Just started using the Kalk early fall so not sure what my daily evaporation looks like for summer yet. In winter i could do slightly over a gallon (like gallon and quarter) been doing about 0.75 gal when doing 2 part with 2/3 of that at night (no 2 part at night).

Also any other tricks to boost pH? i saw something about feeding effluent into skimmer to help off gas but i'm not sure about that or if there could be other consequences of precipitation inside skimmer. Effluent drips in right before fuge at moment and kalk drips in right at the exit of the fuge before bubble trap leading into return area. My probes are in return area (had been in skimmer section prior to adding the effluent line and had been doing 2 part into return).

Thanks again

 

[sergeysailor]

Put reactor effluent near skimmer water input, it is not making any participation inside skimmer or other negative results.

 

[Randy Holmes-Farley]

Thanks. I'll aim for this. Should I aim to be consistent with rate of both throughout the 24 hours or should i lean a little heavier into kalk overnight (like a 3/5 night 2/5 day ratio) to help with pH?.

There's no perfect answer.

Dosing kalwkasser at night tends to stabilize ph but destabilizes alk, while dosing kalk durign the day stabilizes alk and destabilizes pH.

 

[Randy Holmes-Farley]

Also any other tricks to boost pH? i saw something about feeding effluent into skimmer to help off gas but i'm not sure about that or if there could be other consequences of precipitation inside skimmer. Effluent drips in right before fuge at moment and kalk drips in right at the exit of the fuge before bubble trap leading into return area. My probes are in return area (had been in skimmer section prior to adding the effluent line and had been doing 2 part into return).

There are, of course, ways to raise pH unrelated to dosing, but degassing the effluent is a reasonable plan. It is unlikely to cause precipitation in most cases since the degree of degassing is usually low and the dwell time in that situation is not that long.