Calcium usage question...

Gwitness · May 28, 2015

For the longest my tank has always used up alkalinity more than calcium....it almost seemed like my calcium was barely being used. Over the also couple weeks my calcium has been getting used up a bunch and I am now dosing 84ml of calcium a day to my 75 ml a day of alk.....I always thought alk was used UK first and then calcium and then mg?? My calcium is currently 395, alkalinity is steady at 8.8 to 9.0 and magnesium is steady at 1300 to 1350....is it okay my calcium is being used up that quickly? And why is it depleting so quickly all of a sudden? Is it just corals growing for once in my life? Haha

JimWelsh · May 28, 2015

What test kit(s) are you using? How old is it/are they? Have you tried any alternative (new or other brand) test kit(s)? Are you dosing manually, or is it a pump? If pump, then could the issue be with the pump? EDIT: Is there any possibility that there was a mistake measuring the calcium when making up the last batch?

Gwitness · May 28, 2015

JimWelsh said:
What test kit(s) are you using? How old is it/are they? Have you tried any alternative (new or other brand) test kit(s)? Are you dosing manually, or is it a pump? If pump, then could the issue be with the pump? EDIT: Is there any possibility that there was a mistake measuring the calcium when making up the last batch?

I use dosers,but that's a good question about if they are pumping out the right amount....I will definitely double check that....as for mixing it I use the brs stuff so it's super easy to mix.....test kit for calcium is salifert and is fairly new and not out of date...however I haven't double checked with someone else's test kit either...

Randy Holmes-Farley · May 29, 2015

There isn't really any way that calcium can be significantly consumed and not alkalinity. Generally, you'll consume about 18-20 ppm calcium for each 1 meq/L (2.8 dKH) of alkalinity. While there are some scenarios where alk is consumed and not calcium (using a sulfur denitrator, rising levels of nitrate, etc.), the reverse isn't true.

So if you see an imbalance it may be due to not making exactly balanced solutions, the dosers not pumping the same volume, water changes messing with apparent demand, additions that you are not aware of (such as from tap water), or measurement error.