Low pH after adding a Calcium Reactor

[Tmtdvm]

I’ve had a Ca Reactor set up for a few weeks now. The pH in my tank is hovering around 7.9 and used to be around 8.1 before installation. My corals seem to be regressing and do not like the change. On the flip side, my Ca and Alk are more stable. Any advice from the pros out there to increase pH without having to dose Kalkwasser, etc in the tank to keep pH up?

 

[SPR1968]

Mine does that all the time, I think you should be fine.

You can start trying to increase pH with additives, CO2 scrubbers etc but I would leave it as it is personally. I’ve been there myself with this and you can do more harm than good

Also check the pH probe isn’t to close to the output on the reactor. I can tell my reactors working because the pH probe picks it up, but I do it like that on purpose

 

[Dkmoo]

I’ve had a Ca Reactor set up for a few weeks now. The pH in my tank is hovering around 7.9 and used to be around 8.1 before installation. My corals seem to be regressing and do not like the change. On the flip side, my Ca and Alk are more stable. Any advice from the pros out there to increase pH without having to dose Kalkwasser, etc in the tank to keep pH up?

I would actually recommend get pH back. Especially if have visual proof that they are struggling. Sure they are adaptable to a degree, but there should be no reason for them to adapt from a better environment to a worse one.

Between 8.1 and 7.9 may not seem much, but remember that the pH scale is exponential. Coral calcification is the formation of calcium carbonate. Alkaninity is made up of mostly BIcarbonate with a small portion carbonate. The concentration of Carbonate (the ion thats most conducive to calcification) is dependent on PH. From 8.1 to 7.9 is an approx 60% drop in carbonate concentration. While corals can use bicarbonate to calcify, it takes more energy and they have to pump the extra H+ ion out. This often results in a more acidic environment inside coral tissue. Long term survival in lower PH is possible but corals will be weaker, more brittle, and more sensitive to environmental stressors.

Calcium reactor has this counterintuitive affect of raising alk and lowering ph because of how carbonic acid (dissolved co2) interacts with your existing buffer and converting to bicarbonate. Chasing the alk/calc numbers will not be helpful to stony coral growth if the resulting drop in pH decreases calcification rate.

Normal alk levels, ie, 8, in normal chemistry relationships would have maintained 8.2 pH. However almost all of our tanks have high co2 issue, so to address, either

1) install a co2 scrubber
2) intake your skimmer air from outside your house
3) open windows , add house plant
4) add refugium, water plant

There is a 5th way - directly dosing carbonates, such as soda ash (sodium carbonate), however doing so may raise your alk too high since its introducing more alk into the system, without knowing yiur current levels and consumption rate, I'm not sure if this will be appropriate.

 

[X-37B]

I run a carx. No ph probe or controller. My ph at night is 7.9 and 8.2 during lights on.
This is pretty common even without a carx as mine ran the same ph without a carx.
Most ph issues are from a reactor that is not tuned correctly, imo.
One reason I do not run a controller or even monitor reactor ph.
Controllers dump co2 via the ph probe and controller.
My co2 is always on so its very stable. Alk varies from 7-7.2 throughout the day.