Alk - is there something I'm missing?

edinphilly · Sep 27, 2016

I know the general info on alk, ca, and mg. In my 29g I was able to keep alk stable at 9 with kalk in my ato. I upgraded (moved everything over) to a 75. Since then I've had trouble keeping up with alk and it is always getting low on me. I didn't add much coral although there is a lot more rock now growing coralline. It's a mixed reef with some easier sps. I would have thought the alk demand would have stayed the same and kalk would keep up. Does the new volume impact alk uptake? Maybe it is just the frags now growing to colony size? Is it normal for alk use to really accelerate? Thanks.

aaron23 · Sep 27, 2016

coralline algae growing on a lot more rock / surface area could be the reason for the uptick in alk consumption

Homer Allman · Sep 27, 2016

coralline eats alk. If you have that growing it's time to start dosing.

nervousmonkey · Sep 27, 2016

+1 and +1 to Aaron and Homer. It's the coralline,

cromag27 · Sep 27, 2016

Your corals could be growing and consuming more.

edinphilly · Sep 27, 2016

The 29 was mature (over two years) so fully coralline rocks. I tripled the amount of rocks when I moved up to the 75 and nearly all the new rock is Tampa Bay Saltwater LR which was fully corallined. I guess I underestimated coralline impact on alk.

Thanks all.

Randy Holmes-Farley · Sep 28, 2016

How are you making your limewater, and what percentage of the tank volume gets added by the ATO each day?

edinphilly · Sep 28, 2016

With the 29 I did saturated in the summer and a little over half saturated in the winter due to higher evap. With the larger volume and adding the sump I now have more evap. I just need to go back to square one and start over in calculating my use rather than try to base it off the tank prior to the upgrade. I'd say I'm replacing just shy of a gallon per day and that will double when the heater starts running in the house.