Starting kalkwasser dosing..

[NewCaliCaptives]

Just be cautious that tanks vary a lot in CO2 exposures and, iirc, ACI used a CaCO3/CO2 reactor at the same time as the kalkwasser.

That said, I used kalkwasser for 20 years without the pH getting too high. In the early years I used less than saturated kalk and then later used full strength to replace all evaporated water. Alk never got too high in my system.

Awesome i’m glad you said that because I was planning on doing a less than saturated kalk as well since this new tank is mostly frags right now. Im thinking a hybrid approach since I don’t necessarily have a PH issue like most do. i.e. just dosing the kalk as an ATO to maintain Alkalinity but hav my GHL spread that out evenly during lights out to help flatten that PH swing.

 

[Randy Holmes-Farley Verified Community Expert]

Awesome i’m glad you said that because I was planning on doing a less than saturated kalk as well since this new tank is mostly frags right now. Im thinking a hybrid approach since I don’t necessarily have a PH issue like most do. i.e. just dosing the kalk as an ATO to maintain Alkalinity but hav my GHL spread that out evenly during lights out to help flatten that PH swing.

I actually think the biggest risk to uncontrolled hydroxide dosing is in low pH, low alk demand tanks, where the alk may get quite high and the pH may stay on the low end.

 

[NewCaliCaptives]

I actually think the biggest risk to uncontrolled hydroxide dosing is in low pH, low alk demand tanks, where the alk may get quite high and the pH may stay on the low end.

i feel like doing it this way wouldn’t be considered “uncontrolled”, i closely monitor PH and am dialing it in

 

[Randy Holmes-Farley Verified Community Expert]

i feel like doing it this way wouldn’t be considered “uncontrolled”, i closely monitor PH and am dialing it in

I mean uncontrolled by alk measurement, which is how almost all alk additives are controlled.

 

[NewCaliCaptives]

I mean uncontrolled by alk measurement, which is how almost all alk additives are controlled.

Right i said using kalk to maintain alk, i was implying maintaining a specific alk measurement BUT just dosing it during lights off to have the side benefit if flattening that PH swing. Sorry if that wasn’t clear. Does that sound good?

 

[Fasthandsslowmind]

I have an oversized Calc reactor for the current state of my fairly new SPS tank. SOO, I started with just a kalk stirrer, dosing 90-100% of my evaporation. Once that couldn’t keep up with alk / calcium demand, I added the reactor.

Now I just cut the o2 off to the reactor except during the late morning / early afternoon periods, and then I run the kalk stirrer at night while the PH is decreasing. It has a pretty obvious and consistent effect on PH and definitely reduces the swing.

So far, so good. Hopefully my tank will continue increasing Calc / alk demand and I can utilize my calcium reactor more.

 

[NewCaliCaptives]

I have an oversized Calc reactor for the current state of my fairly new SPS tank. SOO, I started with just a kalk stirrer, dosing 90-100% of my evaporation. Once that couldn’t keep up with alk / calcium demand, I added the reactor.

Now I just cut the o2 off to the reactor except during the late morning / early afternoon periods, and then I run the kalk stirrer at night while the PH is decreasing. It has a pretty obvious and consistent effect on PH and definitely reduces the swing.

So far, so good. Hopefully my tank will continue increasing Calc / alk demand and I can utilize my calcium reactor more.

sounds similar to my thought process as well, glad to see it’s working for you

 

[Randy Holmes-Farley Verified Community Expert]

Right i said using kalk to maintain alk, i was implying maintaining a specific alk measurement BUT just dosing it during lights off to have the side benefit if flattening that PH swing. Sorry if that wasn’t clear. Does that sound good?

That's perfect, and how it has been done by many folks since before I got into the hobby in the early 1990's.