Calc/ALK Levels?

NanaReefer · Jan 29, 2016

Hi Randy.

I've recently switched salt mixes from RC to IO. So far in the past 30days I've done 10g WC of 47-50g total volume.

My Calc has dropped significantly from the usual 440 to 340. So I bumped up the auto doser from 39ml daily to 42ml. After 3 days there has been no change. Should I go to 45ml daily? Seems like a lot.

Stranger yet is I've not had to increase my ALK (8.4) dosage nor mag (1440)

I've always dosed equal amounts of Calc/ALK in the past with great results.
Is it common to have to dose more of one? I do still have a slight precipitation showing on my heater, but not as bad as it once was. Stoney corals look good/growing.

I'm not use to my numbers being outta whack-lol.

Randy Holmes-Farley · Jan 29, 2016

Normal Instant Ocean has lower calcium but not much lower alkalinity or magnesium compared to Reef Crystals, so your results are not surprising. Unbalanced dosing is most typically caused by imbalances in the salt mix used, and normal IO is definitely balanced toward too much alk relative to calcium.

The amount you need to dose to make up from a low value (like now) will be higher than to maintain the higher value, so I'd raise the calcium dose for a while, but then expect to have to reduce it a bit in the future as you get to your target.

NanaReefer · Jan 29, 2016

Thank You very much Randy [emoji2]

Randy Holmes-Farley · Jan 30, 2016

You're welcome.

Happy Reefing.

NanaReefer · Feb 12, 2016

Updating with concerns. Recently finished my 3rd wc using IO. Since 1/29 my Calc has risen from 340 to 355-360 only. I'm dosing 16ml 3x daily for a total of 48ml of BRS 2part. My ALK however has been steady at 9, mag at 1400.
The only coral showing a lot of growth is my Birds Nest. Could just this one coral be responsible for the Calc uptake? The tank is dominant LPS/SPS.
Could the clumping SB be responsible? Combination of the two?
I fear having my Calc this low, yet it's a steady low. Not sure what to do. Only precipitation I'm seeing is a little on my heater and the clumping SB.

Randy Holmes-Farley · Feb 12, 2016

IO has lower calcium than RC. In fact, it's the primary difference that I know of, aside from vitamins and chelators in RC. It is going to be below 400 ppm.

So you may want to boost the IO itself with some calcium. I used to do that, but found it unnecessary with the method of calciuma nd alkalintiy I use (limewater) since it over-adds calcium.