What are the limits of 2 part?

Randy Holmes-Farley · Jun 30, 2021

If the calcium product is adequately pure (don't know if the one you are using is), I do not think that raising calcium needs to be done particularly slowly. 50 ppm per day seems OK.

When using a product of unknown purity, I'd go slower. Spread it out over more days in case it has excessive metals, ammonia, etc.

NabberNate · Jul 12, 2021

Thank you very much. I am having trouble with the math on Alk and you're help or a resource is very much appreciated. My aquarium is a 200 gallon system and the ph is 8.07. After making a gallon of the Alk per recipe 1 (470 grams instead of 524) how much should be added to get it up to 8.4?

I calculate the entire gallon would raise my dkh by 21 but what does that mean in terms of ph?

My dkh is also 6. Do I just shoot for a dkh of ~10 and let the ph adjust on its own?

Randy Holmes-Farley · Jul 13, 2021

NabberNate said:
Thank you very much. I am having trouble with the math on Alk and you're help or a resource is very much appreciated. My aquarium is a 200 gallon system and the ph is 8.07. After making a gallon of the Alk per recipe 1 (470 grams instead of 524) how much should be added to get it up to 8.4?

I calculate the entire gallon would raise my dkh by 21 but what does that mean in terms of ph?

My dkh is also 6. Do I just shoot for a dkh of ~10 and let the ph adjust on its own?

There's no way to easily calculate the pH rise, and you should never dose anything based on pH.

Base the dose on your alkalinity need, and see what ph you get.

That said, a 1.4 dKH boost to alkalinity instantly using sodium carbonate will boost pH be about 0.6 pH units, depending on many variables. The pH will drop back over time, and if you add that 1.4 dKH more slowly, the rise will be smaller.

NabberNate · Jul 13, 2021

Your post brings up a valid point I was wondering about. I don't really have a ph / alkalinity need at the moment as I'm fish and invertebrates only I just figure it's better to be towards the middle or upper end of the range if it tends to be low. My goal is to get an automated top off and dose the three part weekly using a 10 gallon container but for now I'm manual. Depending on how quickly my ph falls I wonder if it's better to wait until I can dose daily rather than have the ph shifts. Probably over thinking it but that's what I do.

Randy Holmes-Farley · Jul 13, 2021

NabberNate said:
Your post brings up a valid point I was wondering about. I don't really have a ph / alkalinity need at the moment as I'm fish and invertebrates only I just figure it's better to be towards the middle or upper end of the range if it tends to be low. My goal is to get an automated top off and dose the three part weekly using a 10 gallon container but for now I'm manual. Depending on how quickly my ph falls I wonder if it's better to wait until I can dose daily rather than have the ph shifts. Probably over thinking it but that's what I do.

Yes, overthinking, IMO. When the dose is low, any pH effects are minimal.

Rarely does anyone get pH too high using carbonate for dosing, unless they also use limewater (kalkwasser).

NabberNate · Jul 13, 2021

So I think the message is to keep alk in range and ph will almost certainly follow. With just dosing alone you can't really control whether PH is on the higher or lower side and it really doesn't matter much either.

Randy Holmes-Farley · Jul 13, 2021

NabberNate said:
So I think the message is to keep alk in range and ph will almost certainly follow. With just dosing alone you can't really control whether PH is on the higher or lower side and it really doesn't matter much either.

No, it won't necessarily follow to a good pH. Often it is too low (IMO), and while many people poo poo it, I think it is important for hard corals if optimizing growth is a goal.

NabberNate · Jul 13, 2021

Randy Holmes-Farley said:
No, it won't necessarily follow to a good pH. Often it is too low (IMO), and while many people poo poo it, I think it is important for hard corals if optimizing growth is a goal.

I'll keep reading your articles. It seems I shouldn't go past 12 dkh for alkalinity and if ph is still on the low side but within range choices are to get rid of carbon, introduce outside air, buy plants, or don't worry about it =)

Randy Holmes-Farley · Jul 14, 2021

NabberNate said:
I'll keep reading your articles. It seems I shouldn't go past 12 dkh for alkalinity and if ph is still on the low side but within range choices are to get rid of carbon, introduce outside air, buy plants, or don't worry about it =)

Plants are nearly useless unless its greenhouse density.

pH is best raised by fresh air, CO2 scrubbers, and very high pH alkalinity supplements (hydroxide).