Water change 500 Gallons on 850 gallon system Kalk question

14 foot reef · Jul 27, 2020

Can I add Kalk to the 500 gallon water barrel to raise DKH to aquarium level, or only RO water ?
If I can't what chemical can I add to freshly mixed salt water to raise DKH to my reefs level ?

bblumberg · Jul 27, 2020

sodium bicarbonate or sodium carbonate

14 foot reef · Jul 27, 2020

bblumberg said:
sodium bicarbonate or sodium carbonate

if PH is low, even though DKH is very high on todays standards (40 year reefer) which one ?

bblumberg · Jul 27, 2020

If your pH is low, I would use sodium carbonate. I typically used sodium bicarbonate to boost the dKH of my makeup water. I use Tropic marin Pro so about 2 tsp per 55g is about the right amount to get the dKH to ~8.5. Lately, I have stopped doing this and let the dKH stay at the ~7.5 it mixes to and let my tank drift down to 7.5 as well.

14 foot reef · Jul 27, 2020

I'm a trail blazzer from the past !!!! 11.2 DKH always. Tank is 17 years old.

bblumberg · Jul 27, 2020

I misread your question. If you want to raise dKH and pH, then sodium carbonate is probably the way to go. Kalk is not very soluble. Another way would be to use a salt that mixes to something close to the KH you are aiming for.

I don't trust this guide 100% since it shows that Tropic marin pro mixes to a dKH of 8.5 (I get closer to 7.5) but it is not a bad place to start.