Dosing Kalk - 2 tanks 2 completely different situations with PH

[WhatCouldGoWrong71]

Is it that I am simply not pushing enough kalk solution through my Max to impact PH? I think I know the answer as my Trident is still letting my DOS using the alk program I have set. Would you max out Kalk to equal 100% of the evaporation?

I mix both 5 gallon buckets the same exact way - 6.5 grams of kalk per gallon. Stirred (not shaken).

Max500 - Current evaporation rate is about 3 gallons a day. I am dosing 4300ML opposite light schedule. My PH drops, it doesn't go up when dosing. I can only think that I am being to conservative with my dosing of kalk. This tank is >4 years old and I am fearful of mucking it up when trying something very new to me, like dosing kalk in addition to my 2 part balling that I have been doing for a long time. Before starting to ease my way into kalk I was dosing 110ML of alk/cal a day. I haven't eased up on that, I just set the rules so that when my alk > 8.5 it stops dosing, and I have my Trident set to test more often. Alk is at 8.3 and Cal is at 490. This is a mixed tank with lots of LPS.

I think the I am doing the opposite on my newer Reefer 250. Tank is 98% SPS. Evaporation is about 1.25 G a day and I am dosing 3500ML a day of kalk (6.5G per g). Alk is 9.08 and Cal is 504. Numbers are higher than I want. I might have too many frags in this tank, 45 or so. My current calcium consumption is 2x my alk consumption in terms of using 2 part to compensate. This tank is only getting standard 2 part plus part C.

 

[Randy Holmes-Farley]

My current calcium consumption is 2x my alk consumption in terms of using 2 part to compensate. This tank is only getting standard 2 part plus part C.

What does that mean? What are you dosing? Not all 2 parts are designed for 1:1 dosing, but as a firm rule, calcium cannot ever be consumed without consuming 2.8 dKH of alk per 18-20 ppm of calcium.

 

[WhatCouldGoWrong71]

What does that mean? What are you dosing? Not all 2 parts are designed for 1:1 dosing, but as a firm rule, calcium cannot ever be consumed without consuming 2.8 dKH of alk per 18-20 ppm of calcium.

Well, my math probably has more meatballs in it when compared to your math, lol. And likely my process is flawed.

I think it's part your recipe, BRS 2 part plus balling

When I measure the consumption of calcium over a 24 hour period it would go from say 470 to 449. I noticed a drop of 21 PPM multiple days in a row. I went to BRS and used their calculator and it determined I needed to add 107.47 ml of calcium. to have it come back.

My DKH drops .8 so say from 9 to 8.2. BRS states that I only need 28.5ML of ALK to bring it back.

This is why I was thinking that my calcium is 2x (or more than) my alk consumption. But I think I may see something wrong here already. But, I'll wait for my lumps before I bare my sole.

 

[Randy Holmes-Farley]

My guess is that the calcium test was just too short to accurately see the demand. In any case, it’s fine to dose as you are now, but I expect calcium to rise over time.

On the kalkwasser, if you aren’t dosing at least 0.5% of the volume each day, I would not expect much pH boost.

 

[disaster999]

On the kalkwasser, if you aren’t dosing at least 0.5% of the volume each day, I would not expect much pH boost.

So with my 400L system Im dosing 2000ml a day of kalk (CaO at 1tsp/gal) which is just at 0.5% of my tank's volume. So should I be seeing a pH boost or not?

Also, Im dosing the 2000ml 24 times over 24 hours and have a pH monitor that constantly monitors my pH. All Im seeing is just a very smooth graph of the pH rises slowly to ~8.3 during the day and slowly back down to ~8.1pH overnight. Im sort of expecting to see a pH spike up a little whenever kalk is dosed on the hour but I cant detect any change at all.

Dosing baking soda manually to bump up the alk levels had more of an effect with the pH as it dropped down to 7.9 from 8.1

 

[Randy Holmes-Farley]

So with my 400L system Im dosing 2000ml a day of kalk (CaO at 1tsp/gal) which is just at 0.5% of my tank's volume. So should I be seeing a pH boost or not?

Also, Im dosing the 2000ml 24 times over 24 hours and have a pH monitor that constantly monitors my pH. All Im seeing is just a very smooth graph of the pH rises slowly to ~8.3 during the day and slowly back down to ~8.1pH overnight. Im sort of expecting to see a pH spike up a little whenever kalk is dosed on the hour but I cant detect any change at all.

Dosing baking soda manually to bump up the alk levels had more of an effect with the pH as it dropped down to 7.9 from 8.1

There's no "should" when spreading out dosing.

If you added that all at once, you'd see a pH boost in the ballpark of 0.2 pH units. If you spread that out over many hours, and let the tank pull in CO2 from the air during that time, the effect will be smaller, and how effective your aeration is will determine how small. It is a fairly low dose. Splitting your dose into 24 smaller doses will only cause a bump each time less than 0.01 pH unit, so you won't detect that individually.

Dosing baking soda (sodium bicarbonate) will have a small pH lowering effect. Dosing sodium carbonate (or baked baking soda) will have a pH raising effect that is about 1/2 of the effect of the kalkwasser per unit of alk added.

 

[disaster999]

That make sense

There's no "should" when spreading out dosing.

If you added that all at once, you'd see a pH boost in the ballpark of 0.2 pH units. If you spread that out over many hours, and let the tank pull in CO2 from the air during that time, the effect will be smaller, and how effective your aeration is will determine how small. It is a fairly low dose. Splitting your dose into 24 smaller doses will only cause a bump each time less than 0.01 pH unit, so you won't detect that individually.

Thanks Randy, This make sense. I guess I was influenced with the huge fluctuation Ive seen other people have shared online.

 

[Randy Holmes-Farley]

That make sense

Thanks Randy, This make sense. I guess I was influenced with the huge fluctuation Ive seen other people have shared online.

There do end up being a pretty large number of folks who need a bigger pH boost.

Is that 2000 mL maxing out evaporation?

 

[disaster999]

There do end up being a pretty large number of folks who need a bigger pH boost.

Is that 2000 mL maxing out evaporation?

Yes 2000ml is my current maximum evaporation rate I see on my tank with humidity sitting at around 40% currently. This will drastically change in the summer when we have 70-80% humidity. Im thinking of installing some fan across the top of my tank just so I could encourage more evaporation in the more humid months just so I could continue dosing kalk.

 

[ReeferA]

On the kalkwasser, if you aren’t dosing at least 0.5% of the volume each day, I would not expect much pH boost.

My guess is that the calcium test was just too short to accurately see the demand. In any case, it’s fine to dose as you are now, but I expect calcium to rise over time.

On the kalkwasser, if you aren’t dosing at least 0.5% of the volume each day, I would not expect much pH boost.

Do you mean 0.5% of the "Evaporated" volume each day?
For example, 100 gal with 5 gal evaporation? Thanks.

 

[Randy Holmes-Farley]

On the kalkwasser, if you aren’t dosing at least 0.5% of the volume each day, I would not expect much pH boost.

Do you mean 0.5% of the "Evaporated" volume each day?
For example, 100 gal with 5 gal evaporation? Thanks.

I mean 0.5% of the total tank water volume, so total of 0.5 gallons of kalkwasser added daily in a 100 gallon tank.

If added all at once, that would boost pH by about 0.27 pH units, then it drops back as CO2 re-enters the tank. Spread out over a longer time and the effect looks much smaller, though 18 h later, will likely be higher.