Dosing question


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Jul 2, 2021
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I use BRS Calcium and Alkalinity powders. Problem is I never made solutions and just dose amount of powder I need mixed into some RODi water. I have been doing this since I started my tank and keep my goals (Ca 420, Alk 7-8). I really have not had any significant problems doing this. My tank is a SPS dominant tank and now the frags are taking off and I have mini colonies forming. I used to be able to dose 1 tsp of the BRS Sodium Bicarbonate daily to maintain my alkalinity. However now I am requiring 2.5 tsp daily to keep my goals between 7-8. I have relied on dosing by hand every day because I liked doing it this way as I knew I would never over dose. Now I am thinking about using a dosing pump.

Question is would I be ok to make a container with 35 tsp of sodium bicarbonate (for 2 weeks worth of dosing) with a certain amount of RODI water and dose it in appropriate daily intervals over the 2 week period? Is this an incorrect way to dose?

Thanks so much for your time
Top Shelf Aquatics

Randy Holmes-Farley

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The supplements can be dissolved into any amount of RO/DI water before dosing (as long as it is enough water to dissolve), but if you make a standard concentration (like my DIY recipes), you'll be able to use calculators and such. You cannot make then a lot more concentrated than my recipes due to solubility limits:


Recipe #2, Part 2: The Alkalinity Part

Dissolve 297 grams of baking soda (about 1 1/8 cups) in enough water to make 1 gallon total.

Recipe #1, Part 2: The Alkalinity Part

Spread baking soda (594 grams or about 2 ¼ cups) on a baking tray and heat in an ordinary oven at 300°F for one hour to drive off water and carbon dioxide. Overheating is not a problem, either with higher temperatures or longer times. Dissolve the residual solid in enough water to make 1 gallon total.

A useful calculator:



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You can dilute your baking soda and calcium chloride any way you wish. For instance, my tank eats about 1/2 teaspoon of calcium a day, so to keep the math easy i set my doser for 8oz total fluid per day and add 1/2 tsp of calcium chloride per half cup (8oz) of stock water. Each 8oz gives me a day. Makes it stupid simple. A gallon of water gives me 16days.

There's obviously a saturation limit for mixing alk and calcium if you want it more saturated. That's the beauty of buying dry dosers..You can mix them how you want. At my personal ratio one gallon gives me 16 days.

One concern. 2.5 TSPs is a lot for just frags. I'm concerned a lot of this might be due to tank maturing, nitrate production, etc. All those things suck alk. Just keep a close eye on it in case it falls.

PICK the Most Tested & Least Tested Parameters of your Tank (Pick 2)

  • Calcium (most)

    Votes: 36 6.1%
  • Alkalinity (most)

    Votes: 418 70.7%
  • Magnesium (most)

    Votes: 5 0.8%
  • Phosphate (most)

    Votes: 45 7.6%
  • PH (most)

    Votes: 62 10.5%
  • Nitrate (most)

    Votes: 53 9.0%
  • Nitrite (most)

    Votes: 3 0.5%
  • Ammonia (most)

    Votes: 13 2.2%
  • (least) Calcium

    Votes: 8 1.4%
  • (least) Alkalinity

    Votes: 4 0.7%
  • (least) Magnesium

    Votes: 48 8.1%
  • (least) Phosphate

    Votes: 8 1.4%
  • (least) PH

    Votes: 29 4.9%
  • (least) Nitrate

    Votes: 11 1.9%
  • (least) Nitrite

    Votes: 174 29.4%
  • (least) Ammonia

    Votes: 235 39.8%