Kalkwasser dosing check-in

[nursedude]

Hello all!

I’ve got a 66‑gallon cube that’s been running since 11/2024 and things finally feel stable.

I recently switched from kalk in the ATO (too many issues) to a Versa dosing kalk 24/7. For what I’d consider a medium‑stocked tank with only a handful of corals, my required daily amount seems high.

I’m dosing 3800 mL/day of BRS kalkwasser. Does that seem excessive for a tank this size? I know coralline can use a lot, but I’m just looking for a general rule‑of‑thumb to make sure this isn’t an outrageous number.

Despite the dosing, my alk still dropped 3 ppm over 3 days, so the demand is definitely real. Just wanting a sanity check from others.

Thanks!

 

[56longroof]

What issues are you having dosing in the ATO? I've been doing this for a year and its been pretty easy.

 

[nursedude]

What issues are you having dosing in the ATO? I've been doing this for a year and its been pretty easy.

We live in Phoenix and the swing in top off water needs season-to-season was hard to regulate. I hoped a pump would be more stable. Alkalinity instability was my issue - this seemed a solution.

 

[caddnima]

When you dose that much of KALK, does it maintain that dkh you want? What is your target anyway?

And yes, for me, I prefer what you just did, that you use a doser vs using ATO for consistency.

I have a 75G and a 50G, and they consume 5 gallon (combined) roughly 1 week to maintain 8 dkh. Just for comparison.

 

[exnisstech]

If the consumption is real and the kalk is maintaining the level desired then the amount dosed must be correct but that's my simple train of thought. Often dosing kalk can not keep up on high consumption tanks and has to be supplemented or some people move to a kalk reactor. I ran a 180g on kalk alone for six years using a dosing pump on a digital timer so similar to your method. I was at 7200ml a day which was just barely under my evap rate. Like you I found adding it to the ATO too in inconsistent. Maybe @Randy Holmes-Farley has an opinion on the amount your using?

 

[nursedude]

When you dose that much of KALK, does it maintain that dkh you want? What is your target anyway?

And yes, for me, I prefer what you just did, that you use a doser vs using ATO for consistency.

I have a 75G and a 50G, and they consume 5 gallon (combined) roughly 1 week to maintain 8 dkh.

Thanks for the thoughtful reply. I’ve been trying to stabilize my alkalinity since installing the pump, but I kept seeing a downward trend: it was daily 3–4 ppm (0.23 dKH) drop using the Hanna ppm checker. The decline has slowed from daily drops to every few days — last Wednesday I was at 136 ppm (7.6 dKH) and yesterday I was at 132 ppm (7.4 dKH). This slow, steady decline has been happening for about a month, and I still haven’t fully matched consumption.

The good news is the daily 3‑ppm (0.23 dKH) drops have slowed, so I think I’m getting close to matching uptake. I’m planning to slowly raise it toward 150 ppm (8.4 dKH) using another form of alkalinity additive.

As I near matching what I believe is uptake I wanted to made sure this volume wasn’t an absurdity high amount - no signs precipitation. I had over dosed a tank previously with two part and am extra cautious now.

 

[56longroof]

We live in Phoenix and the swing in top off water needs season-to-season was hard to regulate. I hoped a pump would be more stable. Alkalinity instability was my issue - this seemed a solution.

Gotcha. My tank is pretty dependable at evaporating 2 gallons a day year round. So its easier for me this way.

 

[Randy Holmes-Farley Verified Community Expert]

Hello all!

I’ve got a 66‑gallon cube that’s been running since 11/2024 and things finally feel stable.

I recently switched from kalk in the ATO (too many issues) to a Versa dosing kalk 24/7. For what I’d consider a medium‑stocked tank with only a handful of corals, my required daily amount seems high.

I’m dosing 3800 mL/day of BRS kalkwasser. Does that seem excessive for a tank this size? I know coralline can use a lot, but I’m just looking for a general rule‑of‑thumb to make sure this isn’t an outrageous number.

Despite the dosing, my alk still dropped 3 ppm over 3 days, so the demand is definitely real. Just wanting a sanity check from others.

Thanks!

In 60 gallons of Water, 3800 mL of kalk adds 1.9 dKH of alk, or less if it is not saturated.

Thst is not excessive for many tanks.

 

[nursedude]

Thanks Randy!

 

[Velcro]

Seems like quite a bit for what I’m seeing in the picture. what’s your calcium doing?

 

[Velcro]

Also I might have missed it but I don’t see what amount of kalk per liter or gallons you are mixing up.

 

[nursedude]

Thanks Randy

Also I might have missed it but I don’t see what amount of kalk per liter or gallons you are mixing up.

I use a 10 gallon trigger container. I mix to saturated Kalwasser 1tablespoon per gallon. I just checked my calcium and it was 420 (Salifert kit). My alkalinity tonight was the same as it was Saturday after
my water change - 138 ppm. I’ll check it again in a few days to see if, fingers crossed, it stays steady.