Ca consumption much out of proportion to alk -- All For Reef

t5Nitro · Sep 25, 2020

Hey everybody,

I'm dosing All For Reef for Ca and Alk. My tank's recommended starting dose is 16mL daily for the given volume. The tank has many euphillia coral and a few SPS. Ca is 400->380, the daily change by 20ppm is probably test error. Alkalinity however is rising 0.1-0.2 dKH daily per Hanna checker without much movement in bringing Ca to a balanced number.

I'm dosing half the recommended AFR, currently 7.5mL per day. I dose in the morning. If anybody has further feedback let me know! I can decrease AFR until I find that it's stable at 8.0 dKH and use 2-part Ca solution to supplement. Let me know if I should be doing anything else. I think the corals love this supplement, but I'm looking for its stability in the numbers. My tank's alk consumption must be considerably low to be bumping my numbers with such a trivial dose, and I'm guessing that's why my Ca has a hard time keeping up given the lack of volume for the Ca component.

Thanks!!

blasterman · Sep 25, 2020

What I suggest doing is not messing/dosing calcium for a few weeks and then test to see how much actual calcium is being used over a longer time period. With the livestock you listed it likely isn't moving much and you're right, 20ppm is borderline actual granularity with most test kits. Unless that's a 10gal tank I wouldn't bother testing calcium more than once a week. Twice a month more like it, and then adding calcium chloride to bring it up to where you want..

Most of us keep calcium at levels much higher than in the ocean and hence we obsess over numbers for no reason because our tanks are saturated with more calcium than is needed. If your calcium drops 50 points over several weeks, lets say from 420 to 370 so what. Won't affect coral and it sure won't affect LPS. When you get large tabling acro colonies then we can talk about better dosing.

Once calcium is parked you can then focus on alk, which is the real variable. Right now you are making the classic mistake of trying to couple alk and calcium together in a low utilization tank and you will go nuts trying to resolve it because the problem doesnt really exist