Chemistry question

[Phil Adams]

Quick question please.
I have a 120 litre plus sump. Fish and softies only, currently using Instant Ocean purple bucket.
Was dosing Kalk and everything was flourishing. I switched to sodium bicarbonate because my Hanna tester told me the ph was too high. I now have to dose calcium and magnesium. Hanna lied to me. My ph is 8.00 give or take.
If you were me, would you stick with the current regime?
Or would you revert to Kalk?
Or would you dose AFR?
Or do something else.
I’m not a chemist, and though I’ve read lots I can’t really understand all the implications.
Thanks folks.

 

[Garf]

Quick question please.
I have a 120 litre plus sump. Fish and softies only, currently using Instant Ocean purple bucket.
Was dosing Kalk and everything was flourishing. I switched to sodium bicarbonate because my Hanna tester told me the ph was too high. I now have to dose calcium and magnesium. Hanna lied to me. My ph is 8.00 give or take.
If you were me, would you stick with the current regime?
Or would you revert to Kalk?
Or would you dose AFR?
Or do something else.
I’m not a chemist, and though I’ve read lots I can’t really understand all the implications.
Thanks folks.

Nothing wrong with a little kalk to maintain alkalinity and calcium. However, if you think traces are important, AFR is ok. There's really no right or wrong choice, baring in mind that softy tanks are low consumption until you grow loads of calcifying algae. Are you doing waterchanges?

 

[redfishbluefish]

Fish and softies only.....I'd dose nothing. You should be seeing minimal drops in alk and calc with only softies.

 

[Mels_Reef]

Personally, I think kalk sucks. It does not have the ph boost that most people think it does, it’s terribly messy with crust everywhere, you have to dose 10X as much product to compare with standard 2 part. Its only advantage that I’ve experienced is its 1 dosing setup instead of 2 and you don’t have to dose calcium separately. I tried to like it out of convenience but its just not a good product compared to standard 2 part. I have all my systems setup with a DOS dosing pump with 2 part and I can get pinpoint accuracy on my daily tests.

Side note, Soda Ash (sodium carbonate) has 5X the amount of ph boost that kalk does and you only dose a tiny fraction compared to kalk. In your situation you’re right, sodium bicarbonate would be the way to go if you’re having high ph issues.

Go with 2 part. Its a little more cost up front but way cleaner and much easier to dial in each component!

 

[Miami Reef]

Side note, Soda Ash (sodium carbonate) has 5X the amount of ph boost that kalk does and you only dose a tiny fraction compared to kalk.

Wrong.

Calcium hydroxide or sodium hydroxide has double the pH boost of sodium carbonate, or soda ash per unit of alkalinity added.

 

[Randy Holmes-Farley Verified Community Expert]

Personally, I think kalk sucks. It does not have the ph boost that most people think it does, it’s terribly messy with crust everywhere, you have to dose 10X as much product to compare with standard 2 part. Its only advantage that I’ve experienced is its 1 dosing setup instead of 2 and you don’t have to dose calcium separately. I tried to like it out of convenience but its just not a good product compared to standard 2 part. I have all my systems setup with a DOS dosing pump with 2 part and I can get pinpoint accuracy on my daily tests.

Side note, Soda Ash (sodium carbonate) has 5X the amount of ph boost that kalk does and you only dose a tiny fraction compared to kalk. In your situation you’re right, sodium bicarbonate would be the way to go if you’re having high ph issues.

Go with 2 part. Its a little more cost up front but way cleaner and much easier to dial in each component!

Lol

Of course that depends on whether you have appropriate expectations.

That said, this statement of yours is either extraordinarily misleading or incorrect, depending on what exactly you mean.

Side note, Soda Ash (sodium carbonate) has 5X the amount of ph boost that kalk does and you only dose a tiny fraction compared to kalk.


Hydroxide, whether from a high pH two part or kalkwasser has twice the pH boost of carbonate fir the same amount of alk dosed.


I prefer kalk to a two part.

 

[Phil Adams]

Nothing wrong with a little kalk to maintain alkalinity and calcium. However, if you think traces are important, AFR is ok. There's really no right or wrong choice, baring in mind that softy tanks are low consumption until you grow loads of calcifying algae. Are you doing waterchanges?

Thanks. Water changes approx 20% every other week.

 

[Phil Adams]

Personally, I think kalk sucks. It does not have the ph boost that most people think it does, it’s terribly messy with crust everywhere, you have to dose 10X as much product to compare with standard 2 part. Its only advantage that I’ve experienced is its 1 dosing setup instead of 2 and you don’t have to dose calcium separately. I tried to like it out of convenience but its just not a good product compared to standard 2 part. I have all my systems setup with a DOS dosing pump with 2 part and I can get pinpoint accuracy on my daily tests.

Side note, Soda Ash (sodium carbonate) has 5X the amount of ph boost that kalk does and you only dose a tiny fraction compared to kalk. In your situation you’re right, sodium bicarbonate would be the way to go if you’re having high ph issues.

Go with 2 part. Its a little more cost up front but way cleaner and much easier to dial in each component!

Thanks. No, I THOUGHT the ph was high thanks to an inaccurate Hanna kit. In reality it’s marginally low and I’d like to increase it a touch.

 

[Mels_Reef]

Lol

Of course that depends on whether you have appropriate expectations.

That said, this statement of yours is either extraordinarily misleading or incorrect, depending on what exactly you mean.

Side note, Soda Ash (sodium carbonate) has 5X the amount of ph boost that kalk does and you only dose a tiny fraction compared to kalk.


Hydroxide, whether from a high pH two part or kalkwasser has twice the pH boost of carbonate fir the same amount of alk dosed.


I prefer kalk to a two part.

Kalk is your preference and that’s ok. I’m not a scientist but I know my dosing habits and numbers very well. Anecdotally, there is no comparison when it comes to potency and ph boost.

There is absolutely no misleading statement here. I personally used kalk as a tryout in an established system I have. I was dosing 30mL of Soda Ash and 20mL of calcium chloride per day. When I shut the two part down and tried kalk, I was having to dose 280mL per day to maintain my numbers. 8.2 Alk and 425 calcium. That’s all the evidence I needed. All 3 recipes mixed to BRS recommended. I even tried a pill mixer on the kalk container to keep it fully saturated at dosing. Little help

My ph dropped from 8.5 to 8.1 daily max on average when I switch from Soda Ash to kalk. There’s just no comparison.

 

[Randy Holmes-Farley Verified Community Expert]

Kalk is your preference and that’s ok. I’m not a scientist but I know my dosing habits and numbers very well. Anecdotally, there is no comparison when it comes to potency and ph boost.

There is absolutely no misleading statement here. I personally used kalk as a tryout in an established system I have. I was dosing 30mL of Soda Ash and 20mL of calcium chloride per day. When I shut the two part down and tried kalk, I was having to dose 280mL per day to maintain my numbers. 8.2 Alk and 425 calcium. That’s all the evidence I needed. All 3 recipes mixed to BRS recommended. I even tried a pill mixer on the kalk container to keep it fully saturated at dosing. Little help

My ph dropped from 8.5 to 8.1 daily max on average when I switch from Soda Ash to kalk. There’s just no comparison.

Well, I will insist that you are mistaken, and the pH boost from hydroxide is clearly larger for both perfectly well understood chemistry reasons and measured to be so in well controlled experiments. It is also reflected in the experiences of many, many reefers over several decades.

I agree that are quite right that two parts are far more concentrated, but hydroxide always has a much bigger pH boost when dosed identically.

Your “numbers” that might incorrectly show a larger carbonate pH boost likely reflect dosing larger amounts at once, which in either case give a larger immediate boost and none later. They may also reflect a larger total alk addition since kalk is limited by evaporation. Both of these issues can be misinterpreted as a larger overall boost for carbonate.

 

[Randy Holmes-Farley Verified Community Expert]

Looking at what you dosed, you dosed far, far more total alk and calcium with the two part, so not unexpectedly, also saw a bigger pH effect.

 

[Mels_Reef]

30mL Sodash solution over 24 hours
280mL Kalk solution over 24 hours
To maintain an Alkalinity of 8.2.

I guess I’m just not understanding the math on how I was dosing “far far more total Alk and calcium”

 

[Garf]

30mL Sodash solution over 24 hours
280mL Kalk solution over 24 hours
To maintain an Alkalinity of 8.2.

I guess I’m just not understanding the math on how I was dosing “far far more total Alk and calcium”

https://reef.diesyst.com/chemcalc/chemcalc.html
https://www.hamzasreef.com/Contents/Calculators/KalkContribution.php

 

[Mels_Reef]

https://reef.diesyst.com/chemcalc/chemcalc.html
https://www.hamzasreef.com/Contents/Calculators/KalkContribution.php

Again, I’m not a scientist so those calculators are overkill to me. I don’t need to understand the science behind it. If I have 2 solutions mixed to standard and 1 takes 30mL and the other takes 280mL to meet my goals, well I’m going with the 30ml solution. That means I have to fill the container much less often, I have nice high ph and no mess.

 

[Randy Holmes-Farley Verified Community Expert]

Using the calculator, and if we assume your tank water volume is 25 gallons, you dosed

0.35 dKH of alk via 280 mL of saturated kalkwasser (assumes you saturated it)

1.7 dKH of alk via 30 mL of my carbonate recipe (BRS uses my recipe)

 

[Randy Holmes-Farley Verified Community Expert]

Again, I’m not a scientist so those calculators are overkill to me. I don’t need to understand the science behind it. If I have 2 solutions mixed to standard and 1 takes 30mL and the other takes 280mL to meet my goals, well I’m going with the 30ml solution. That means I have to fill the container much less often, I have nice high ph and no mess.

That is certainly the benefit of a two part. No one disputes that they are far more potent.

 

[Mels_Reef]

Using the calculator, and if we assume your tank water volume is 25 gallons, you dosed

0.35 dKH of alk via 280 mL of saturated kalkwasser (assumes you saturated it)

1.7 dKH of alk via 30 mL of my carbonate recipe (BRS uses my recipe)

I see what you’re saying, and I am sure you are 100% accurate in that science. That doesn’t discount the fact that you can’t concentrate the kalk solution any more to allow you to dose less. So my original comment is accurate. You dose about 10X more kalk solution than you do soda ash solution to achieve the same results(approximately).

 

[Randy Holmes-Farley Verified Community Expert]

I see what you’re saying, and I am sure you are 100% accurate in that science. That doesn’t discount the fact that you can’t concentrate the kalk solution any more to allow you to dose less. So my original comment is accurate. You dose about 10X more kalk solution than you do soda ash solution to achieve the same results(approximately).

The ratio is more extreme. The two part you are using is 46x times more potent, although you do need to dose that amount of each part, and it is desirable to use a third part with it to avoid ionic imbalances.

These may be interesting reads:

https://www.reef2reef.com/ams/pros-and-cons-of-alkalinity-and-calcium-dosing-methods.1069/
https://www.reef2reef.com/ams/how-a...-calcium-system-works-and-why-it-matters.958/

 

[Phil Adams]

Thank you chaps for your input, however I’m finding it all a bit confusing relating this info to my original questions.
Could somebody point me in the right direction please?
Many thanks

 

[Randy Holmes-Farley Verified Community Expert]

I did not respond since I thought others already answered. There are plenty of good ways to supplement calcium and alk (all detailed in the article linked above), and none is clearly best.

Your pH is fine. I don’t think it matters much for your tank which alk/calcium method you use, but I’d consider a trace element supplement even if you elect a method already adding then (like AFR) since you will be using relatively little of any alk/calcium method for a soft coral tank.