Low Alkalinity and Calcium Levels

ReeferDave71 · Jul 20, 2019

Using 150ml/day of ESV 2 part in a 110 gallon DT, only keeps Alk at 7.3 and Cal at 375. This is above the maximum recommended dose of 1ml/gal/day of each as per ESV.

Tank has light to moderate LPS and only some SPS and coralline algae. Any decrease in the dosing amount causes both levels to drop. Magnesium is at 1425 and all tests have been done with different test kits.

Not sure what's causing the high consumption or how to increase the Alk and Cal safely.

Martin Kuhn · Jul 20, 2019

If your tank really has „only“ 110 gal total water volume this is a pretty high consumption of
Alk 2,8 KH and Ca 22 mg/l per Day.

Tanks which are super stuffed with SPS reach a consumption like that.

- take a closer look on the total water Volume of your System. Is it really „only“ 110 gal or is there some more water in Refugiums etc. than the consumption would be more realistic and I would recommend to increase the dose.
- even if you wrote that you 2x checked the values, take a closer look again. Which test kits did you use. Did you check salinity also during 1st and 2nd Test and it did not change?

ReeferDave71 · Jul 20, 2019

There is a 10 gallon sump, but it also has live rock in it. Two versions of Salifert Calcium test kits and several bottles of Hanna reagent for their alkalinity test gave similar results. A Salifert dKh kit showed almost 1 dKh lower. Salinity is 1.025

rkpetersen · Jul 20, 2019

If you have extensive coralline algae growth, that can be consuming a lot of it.
Also make sure you don't have a lot of abiotic precipitation going on.
Look for white deposits in the sump, on pumps, heaters and powerheads, and in sand (sand becomes hard, like limestone.)
If your two dosing tubes are positioned close to each other, consider moving one of them.

ReeferDave71 · Jul 20, 2019

There is minimal coralline growth, and besides some very small clumps of sand, not really anything in the way of white deposits.

There is some buildup at the 2 part discharge tubes in the sump. I can try and separate those more the the 1-1/2 they currently are.