PH charts dosing kalk the ACI way

[BAMatter]

Can y’all post some screenshots of your PH graphs who dose PH based? I peg my PH at 8.31-8.32 at night and it rises upwards of 8.41 during the day dosing Triton Core 7. Just wondering if this is a fairly common path for PH to take. I’m usually around 2000ml’s of kalk after lights off on a system that’s about 85 gallons total. Thanks.

 

[Randy Holmes-Farley]

Can y’all post some screenshots of your PH graphs who dose PH based? I peg my PH at 8.31-8.32 at night and it rises upwards of 8.41 during the day dosing Triton Core 7. Just wondering if this is a fairly common path for PH to take. I’m usually around 2000ml’s of kalk after lights off on a system that’s about 85 gallons total. Thanks.

I think folks need to understand that dosing kalkwasser based on pH will have highly variable results depending on the demand for alk and the sources of CO2 present. Just today, someone had alk at 16 dKH and rising from dosing too much kalkwasser without the pH becoming what I consider excessive.

If it works in your setting, great. I like limewater (kalkwasser) and dosed it as the only alk and calcium supplement for 20 years, but I do not recommend dosing it based on pH rather than alk control, at least until you determine what happens to both over time. I dosed it by ATO and neither the pH nor the alk ever got excessive.

 

[BAMatter]

I think folks need to understand that dosing kalkwasser based on pH will have highly variable results depending on the demand for alk and the sources of CO2 present. Just today, someone had alk at 16 dKH and rising from dosing too much kalkwasser without the pH becoming what I consider excessive.

If it works in your setting, great. I like limewater (kalkwasser) and dosed it as the only alk and calcium supplement for 20 years, but I do not recommend dosing it based on pH rather than alk control, at least until you determine what happens to both over time. I dosed it by ATO and neither the pH nor the alk ever got excessive.

Thanks Randy! Yes, this has been an ongoing thing with some trial and a lot of maths looking at amounts, times, etc. I have been testing alk daily for a bit now, occasionally a spot check in the am, so see how everything is reacting. That said, my alk has been remaining pretty tight, and it’s been taking additional 2 part to bring up. Obviously systems run very differently, I just wanted to see if PH rising to 8.41 from an 8.32 hard line is that out of the ordinary, considering the amount of Kalk I need to dose to keep the 8.32 at night.

 

[Randy Holmes-Farley]

That said, my alk has been remaining pretty tight, and it’s been taking additional 2 part to bring up.

IMO, those are the scenarios where kalkwasser can be dosed at will. It's the low alk demand scenarios (where kalkwasser may provide more alk than the demand) that are most problematic for pH based dosing.

In my case, for example, I could have been dosing based on pH or alk, but instead just dosed all evaporated water as saturated kalkwasser (at least for the last decade of my reef), before that I dosed less than saturated) because I knew neither pH nor alk would get too high.

 

[Pntbll687]

I think folks need to understand that dosing kalkwasser based on pH will have highly variable results depending on the demand for alk and the sources of CO2 present. Just today, someone had alk at 16 dKH and rising from dosing too much kalkwasser without the pH becoming what I consider excessive.

If it works in your setting, great. I like limewater (kalkwasser) and dosed it as the only alk and calcium supplement for 20 years, but I do not recommend dosing it based on pH rather than alk control, at least until you determine what happens to both over time. I dosed it by ATO and neither the pH nor the alk ever got excessive.

Randy,

Do you think adding a CO2 scrubber to a system will impact the effectiveness of using kalkwasser? Not in terms of effect on ph, but in the kalk not being able to form alkalinity because some may be removing CO2 that the kalkwasser needs?

 

[Randy Holmes-Farley]

Randy,

Do you think adding a CO2 scrubber to a system will impact the effectiveness of using kalkwasser? Not in terms of effect on ph, but in the kalk not being able to form alkalinity because some may be removing CO2 that the kalkwasser needs?

Nope. At any pH you’d find acceptable, there’s almost no hydroxide remaining. At pH 9.0, the alk due to hydroxide that has not combined with bicarbonate or CO2 is only 0.01 meq/L or 0.03 dKH. It drops about a factor of 2 for each 0.3 pH units down from there.