question about mixing limewater


New member
I am mixing MRS. Wages lime with RODI water in a 5 gal. bucket ahead of time and then pump it into a resv. for ATO application. my questions is at the mixing bucket...there is slurry at the bottom of the bucket, can i just add more RODI and stirr for a future batch or do i need to toss the slurry and start from scratch every batch? if adding more water is fine does this affect the concentration of the mix over time?


Active member
I've always just tossed out the "slurry" at the bottom and started from scratch. No sense risking it especially with something so cheap as KW is :)


-RT * ln(k)
You can just add more water. That slurry has an added benefit in that if any heavy metal contaminates were to make it into your source of kalk somehow, the slurry on the bottom will pull them out of solution effectively purifying bad kalk. It isn't a must and you can certainly throw it away if you want to. But there are some possible benefits for making more up on top of what didn't dissolve last time.


New member
so if i do not toss the slurry every batch do i still need to add 2 tbsp per gallon in addition to the slurry?


Team RC
so if i do not toss the slurry every batch do i still need to add 2 tbsp per gallon in addition to the slurry?

Fully saturated limewater is made with 2 Teaspoons of lime per gallon. You will still need to add more lime each time you mix if you only add enough to fully saturate the water you are mixing right then. Alternatively you can add a large amount of lime, say a pound, and then refill as necessary. The excess lime will settle to the bottom with the slurry and dissolve upon the addition of fresh water. With a little math you can guesstimate how many gallons you will get per pound and add more accordingly.


Premium Member
If you're adding 2 tbsp per gallon, then a lot of the slurry likely is lime, and it'll dissolve when you add some fresh RO/DI water. Otherwise, the slurry at the bottom likely contains various impurities and some calcium carbonate, from carbon dioxide reacting with the lime. The slurry won't cause any problems.