Kalkwasser time

Chris A.

Formally toomanyfish
BRS Member
You can use both. You’ll have to dial both , calc reactor and kalk at the same time. You’ll have to figure out what works best for you as there’s a lot of ways to set both up. I’d personally use the same amount of kalk and use the calc reactor to offset the increasing demand of the tank ( max the kalk and dose the rest with the calcium reactor)


Well-Known Member
BRS Member
To your question, I don't think people intentionally wait. Kalk in my container, mixed to exceed saturation, settles reasonably fast. Besides, at worst, I would only be adding about 500ml every 6 hrs of cloudy kalk water, which isn't significant. I cannot imagine there is a substantial difference between cloudy kalk solution and saturated solution, after 15 minutes of settle time.

To comment on some other posts, it is really hard to dose exact measurements of anything, let alone kalk, without substantial maintenance and calibration. The dosers seems to fluctuate, human error reading chemicals or calibration, etc. The flow of the doser changes, so without constant calibration, the exact amount can change. But since it doesn't really matter whether you add 500 or 520mls, no one truly cares. Testing + water changes will put things back to spec range. As long as you are consistent, then things will be fine, methinks.

Adding kalk in top off water may be convenient, but not that exact. Top off requirements change per season and with AC or heat. If you can, perhaps consider setting up an ato with fresh ro water. Then, with a doser add saturated kalk up to the tank as needed. If you end up putting more saturated kalk than evaporation, you will need to add something else, like 2 part or a calcium reactor. Back off the kalk so as not to flood.

Kalk is cheap, easy to dose, caustitc to breath, but also has a limit. If you have clams, lots of growing SPS, then it is highly likely you will need to supplement.

Not that my setup is an example to be followed, but I use a 10 gallon ATO reservoir. A 10 gallon saturate kalk reservoir, which I add 2 cups or so powder kalk then just add water afterwards (it is covered) stirred to make saturated. Then I have 2 2.5 gallon water jugs that store Randy's 2 part (alk / ca). I dose about 1500ml of kalk, and 300 ml of each 2 part, each day. I have a bottle of mag+ will must be used up each time I refile the 2 part jugs, which is added to the water reservoir periodically. My jugs last about a month. I have very low demand, but the clams and snails seem to consume everything. Not entirely sure where it all goes...

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