Kalk Doser drives PH too high, but Alk is low.

[static416]

Previously had a Red Sea XL300 (65gal display + 15gal sump) that was fairly heavily stocked and always had a problem with keeping pH above 7.9 or so. With a combination of a Kalk reactor and external air for the skimmer, I managed to fix that. It would solidly sit at about 8.3. But that's old news.

I just upgraded to a Waterbox 230 LX (160gal display + 60gal sump) and with the Kalk reactor connected, I now have a steady pH of 8.5-8.6 with pretty light kalk dosing. However, the alk is flat at about 7.7-8 at best, far from the 10-11 I usually ran at previously.

If I crank up the kalk, I can likely raise the alk, but it'll blow the pH past 9 easily (went to 9.5 briefly the other day by accident).

Am I doing something obviously wrong?

I'm having to keep kalk low, and dose 180ml of All-for-Reef a day to keep the alk flat near 8 without spiking the pH. That's getting expensive.

Another option is buy a ton more fish I guess?

 

[static416]

Maybe my answer is here

You are right, they typically don’t. You cannot get more than about 2 dKH per day from kalkwasser with typical evaporation rates.

Really not excited to buy a calcium reactor on top of the kalk reactor.

 

[John K]

kalk is useful for keeping up with demand (to a point), but not for raising levels for the reasons you are encountering. Correct levels with two part or other additives, then maintain with kalk, and you’ll likely have better luck.