Why does kalk fall out so quickly?

[Bubblebass]

I have moved from mixing in my ATO to mixing in a bucket and siphoning into the ATO. I found that 1 tsp/gallon works for my system. I do the "mix once and done" method in the bucket then siphon with as little disturbance as possible..

If the water becomes fully saturated at approx 2 tsp/gallon, why is it that when I mix with half of that, so much falls out of suspension immediately?

 

[chipmunkofdoom2]

Per Randy's article on calcium hydroxide, it's unlikely that the solids on the bottom of the limewater reservoir are undissolved calcium hydroxide, especially when you're not saturating the mix. It's more likely calcium carbonate, magnesium hydroxide, or other impurities.

 

[Randy Holmes-Farley Verified Community Expert]

I agree it is likely other things, and undersaturated limewater always collects these solids.