View Full Version : Kalkwasser questions with ATO.

12/17/2010, 04:16 PM
I am about to start dosing kalkwasser through my auto top off system. I just have a couple quick questions before I jump in.

1. My pH right now typically runs pretty low (7.8-7.9). I evaporate at around 1.5 gallons a day, which means I will be adding roughly 3 teaspoons of kalkwasser to the tank on a daily basis. I am going by the recommended 2teaspoon per gallon of water. Is this safe range for my pH as I dont want it to rise to high.

2. How long does the kalk mix need to be stirred for? Should the solution turn clear, or will it only turn clean once it settles. If I am mixing the solution in a separate 5 gallon container, is it OK to mix it for say 5-10 minutes, then add to my ATO? Once I add to my ATO container, I would leave it off for an hour or so to settle. Does this sound right?


12/17/2010, 04:25 PM
Kalk generally turns clear when it settles, although sometimes it remains cloudy. I wouldn't worry in either case. You only need to mix it for a few seconds, at most. I gave my 5 g containers a quick stir 2-3 times, and they were fine. More aeration just adds more carbon dioxide to the container, which converts the kalk to fine sand.

If your ATO adds kalk a drop at a time and is fairly sensitive to level changes, the system likely will be okay, but I'd watch the pH carefully for the first few days.

This article goes into details:


12/17/2010, 04:27 PM
This is the the product I use right here (http://autotopoff.com/products/DT1/). Its pretty sensitive, but definitely not a drop at a time. Its a steady stream when the ATO turns on, and I would say it refills about 2-3 cups at a time.

12/17/2010, 05:51 PM
I just did a little test. While I was standing near the tank I heard the ATO unit turn on. Right away I was able to start my stopwatch on my phone to count how long it added water to the tank. The ATO ran for 2 minutes and 5 seconds. Then what I did was take a bucket and put it under the ATO for that same length of time to see how much water is added to the tank when the ATO turns on.

It ended up being 4.75 cups in that 2 minutes and 5 seconds. So that means each time the ATO turns on, it will be filling 33% of a gallon, so roughly 1/3rd of a tea spoon of Kalkwasser.

Again, the ATO doesnt drip, its a steady stream being pumped by a maxijet through tubing the same size as RODI tubing.

Sound safe?

on the spot
12/17/2010, 06:49 PM
Well, how big is your system?

4. Delivering a small amount of limewater all at once. Adding 1.25% of the aquarium’s volume (1.25 gallons of limewater per 100 gallons of aquarium water) as saturated limewater all at once raises the pH by 0.6 to 0.7 pH units. Such an increase is clearly too large. Adding a smaller portion all at once can, however, be acceptable. Adding, for example, 0.25% of the aquarium volume (0.25 gallons or 1 L of limewater per 100 gallons of aquarium water) will raise the pH by only 0.1 to 0.2 pH units. Unless the pH is high (>8.4) before the addition, that amount is likely acceptable. The other concern with all-at-once dosing is that the local pH in the area of the addition will rise considerably higher than the values above. So dosing must be done far from living organisms, and in high flow areas that will facilitate fast mixture. In some aquaria, such restrictions make all-at-once dosing of limewater prohibitively risky to living organisms.

I might pinch the hose if there were some concerns...Make the pump run longer to reach the shutoff.

12/17/2010, 07:09 PM
Ive been doing what you are doing for 2 months now with no ill effects. My ATO pump is an aqualifter though, probably delivering a couple cups at a time.

12/17/2010, 07:39 PM
Sorry for not mentioning it, its a 92g corner tank with no sump.

12/17/2010, 10:41 PM
I have been adding kalk to my make up water for years. IT works great! I use a ATO Tunze system. I have the outlet right in front of my skimmer in the rear chamber of my 34 gallon RedSea Max SPS tank. This helps precipitate some phosphates out of the water as well.
A PH meter in the tank would help you see what effects it has in the tank after a dosing cycle occurs.
Also bear in mind, you can adjust the kalk per gallon to any ratio you would like. So, if you feel it effects ph too much you could cut back how much is used per gallon.
Also, I keep my pump inlet tube in my container approx 3 inches above the bottom, this way you are siphoning off the clear water and leaving the heavy kalk sitting at the bottom.
Works well for me. I have been doing it this way for over 10 years! Started out doing it with a Kent float valve and just using a siphon!
Let us know how it works out for you.

12/17/2010, 10:42 PM
I recently switch my kalk water ATO to an aqualifter pump. I like the quarter inch tubing to slow down the fill. Mine only runs for a minute or so at a time, but, it's going through close to 2 gallons a 24 hour period. I filled my 5g bucket to almost the brim, and 24 hours later it's over half gone. :(

So far, no ill effects from the corals.