Limewater question

geomarq · Nov 13, 2014

Does limewater slowly increase alkanity? I canâ€™t find this info. anywhere. I know it adds both hydroxide and calium ions, but can my kalk mix somehow be providing more hydroxide ions than calcium? Like a 2:1 ratio sort of thing? Iâ€™m trying to figure out how to keep alkanity stable.

Iâ€™ve determined that my alkanity creeps up from 8 dkh (this is with the water change & salt mix used) to 9/10 dkh by the second week. Consistently.

I do biweekly 60gl water changes, I have relatively small amount of corals and use only limewater in a reactor for the CA & Alk. needs (combined with water top off).

Randy Holmes-Farley · Nov 13, 2014

Limewater adds both calcium and alkalinity, and in about the right proportions for consumption within the tank.

If you dose it in an appropriate amount, to balance the demand for alkalinity, alk will be unchanged. if you dose less then it will drop, and if you dose more, it will rise.

Limewater will never add too much alkalinity relative to calcium. If the alk is creeping up, add less limewater (or put less lime into the same amount of limewater).

geomarq · Nov 13, 2014

OK, but is there another culprit to why only my Alk. keeps creeping up?

Ty.

Randy Holmes-Farley · Nov 13, 2014

If you dose limewater sufficient to boost alkalinity by 2 dKH (8 dKH to 10 dKH), the calcium will only rise by about 14 ppm, which will hardly be noticeable with most calcium kits.

Then the water change messes with both calcium and alkalinity since the new salt water probably doesn't exactly match the tank.

Long term, there are small effects, but not what you are observing. It is the subject of a current Reef Chemistry Question of the day which I'll post an answer tonight or tomorrow morning.:

https://www.reef2reef.com/forums/re...try-question-day-57-limewater-kalkwasser.html