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Alkaline & acid buffer formula for desired dKH

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  • Alkaline & acid buffer formula for desired dKH

    Dear Seachem

    A few days ago I got the chance to purchase a set of Seachem alkaline and acid buffer for my freshwater aquarium and couldn't be any more happy. After reading the instructions on each buffer everything seems quite straight forward but there's just one question I'd like to ask is to finding out the math formula to calculate how many grams of each buffer I need to add to get the right dKH.

    Alkaline buffer instruction
    To increase pH, use 1 teaspoon (6 g) for every 80 L (20 gallons) daily until desired pH is reached (this dose raises alkalinity by about 1 meq/L (2.8 dKH))

    Acid buffer instructions
    To lower pH, use 1/4 teaspoon (2g) for every 80 L (20 US gallons) daily until desired pH is reached (this dose lowers alkalinity by about 0.2 meq/L (0.6 dKH))

    Currently I'm trying to get a ph of 7 and a dKH of 7 in a 5 gallon bucket of RO water. It mentions I need ratio of 2/1 of alkaline & acid buffer to get a ph of 7. But now I'm confused on the part on how to find out the right amount to add in order to get the desired dKH, please correct me if my math is wrong.

    Since the ratio for the PH is 2 to 1, i need to change the change the instruction dosage from 6g of alkaline buffer to 4g instead since I'll be taking the acid buffer instruction of 2g into account.

    6/4g = 2.8dkh/x x=1.866dkh

    So assuming I'm making sense 4g of alkaline buffer for every 20 gallon will increase alkalinity by 1.866kh

    Then for everyone 4g of alkaline buffer i'll be adding 2g of acid buffer, assuming I'm not wrong, I'll need to take the 1.866kh and minus it by .6dkh, leading to a increase in 1.266dkh for every 4g-alkaline/2g-acid buffer I add into a 20 gallon container.

    Then to to achieve a dKH of 7, I'll need to divide 7 by 1.266 = 5.53 doses of 4/2g of alkaline/acid buffer

    But then since I'll be using a 5gallon bucket instead of dosing for 20 gallons I should divide 5.53 doses by 4 = 1.38 dose of 4/2g of alkaline/acid buffer

    Then a dose of 1.38 x 4g = 5.52g of alkaline buffer
    1.38 x 2g = 2.76g of acid buffer

    Not sure am I right or wrong or making any logical sense but is 5.52g of alkaline and 2.76g of acid buffer the right amount to get a 5 gallon bucket of RO water to 7ph and 7dKH? Sorry my awkward tone and many thanks in advance.

  • #2
    Thanks for the post! I would recommend using our Dose2 app, available for apple or android devices. This app will make your life so much easier! :)

    For a 5 gallon of RO water to target a dKH of 7 and pH of 7, add the following:

    Alkaline Buffer = 1.8 teaspoons or 12.2 grams
    Acid Buffer = 0.9 teaspoons or 6.1 grams

    I hope this helps!


    • #3
      Sorry dun to be doubtful or anything, but this is the part where I get really confused, on the Seachem Doser app for my Android it only lets me enter 3 units of data, which is the water volume 5 gallon, current KH 0 meq/L and desired KH 2.5 meq/L but nothing is listed for the desired pH. But even if only entered the 3 units(5gallon, 0meq/L kh & 2.5meq/L kh), somehow it tells me to add 4.37grams of alkaline buffer instead of 12.2grams. Please forgive me for my direct/blunt tone(stupid old anger mental meds side effects).
      Last edited by Submarine Street; 04-28-2017, 22:49.


      • #4
        That is actually my fault! I entered it wrong by putting 7 instead of 2.5 for meq/L!

        Ok, so if you enter 5 gallons, current KH 0 and desired KH 2.5 it will show you that you need 0.6 teaspoons or 4.4 grams of Alkaline Buffer. However, if you click on the link below that states "Target pH with Acid Buffer", it takes you to a new screen where you can choose your desired pH. For a pH of 7.0 it should say to add the following amounts:

        Alkaline Buffer = 4.4 grams
        Acid Buffer = 2.2 grams

        Again, I'm so sorry for the earlier mistake! Does this make more sense and are you able to replicate this on your end?


        • #5
          Somehow I wasn't able to find the link in the app or the calculator page for the target ph and acid buffer, but by any chance would you have the link to it, many thanks. :3


          • #6
            I'm not sure I understand your question, but I have attached a couple of screenshots that may help. Let us know!
            Attached Files