Kalk, Vinegar, Carbon dosing % questions


New member
My tank is a mixed 35ish gallon (30 display 10 sump) and right now my CA/ALK/MAG levels have been perfect for months and I do not want to alter that. I feed my tank a LOT, definitely more than others.

I use 3.7 tablespoons of Kalk to every 5 gallons of top off water which lasts me almost a week.

My P04 jumped up to toughly .10ppm recently, and I like to keep it around .05-.07. I am not one to chase numbers, and I have seen better color around the .08 area in my SPS, but I would like to start a regimen now then wait until it gets out of hand. And just to note I am pretty sure I have low bacteria in my tank as it is. Almost no visible algae at all. I usually see a light hazing on my glass after 2 weeks.

So my main question is adding Vinegar to my Kalk mix. I do understand this will increase the Calcium percentage, and decrease PH which isn't that much of an issue for me. Once Vinegar is added it starts populating bacteria which in turn removes P04 which is all removed with skimming.

What percentage of Vinegar (if dosed continuously) is a fair LOW amount that can be added to Kalk without getting into trouble? Also just remember this will be sitting in a 5 gallon jug for almost a week if that makes any difference.

Ive read 15ml per TeaSpoon Kalk. I use 3.7 per 5 gallons. So thats = 52.5ML of Vinegar.

Any info is much appreciated.


Premium Member
15 ml of vinegar per teaspoon is an upper limit for increasing the amount of Kalk dissolved per gallon. I'd probably start with half that, and see how it goes. Some tanks have issues at the full 15 ml per tsp, although that's rare.

The vinegar will increase the calcium content of the Kalk only slightly unless there is precipitate or leftover Kalk in the container. That precipitate might dissolve with the vinegar added, and some of that precipitate might contain calcium.