reefer125g
Non-member
Does 5 tsp a day of baking soda seem like alot in a 200 gallon sps system . My ca and mag is stable at 420 and 1350. But ALK drops every day.
Alk question
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Terry Martin
Well-Known Member
Just ballpark figure from how often I fill dosing reservoir, but i'd say i use about 9 tsp a day of soda ash for 350 gallon mixed reef, sps dominant.
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reefer125g
Non-member
What 2 part are you use ? I am doing Randy's two part of dow flakes and baking soda . I am at 60 ml of CA and 105 of ALK mix a day and still fighting to keep ALK up. Trying to stay at 8.5
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reefer125g
Non-member
Ca is stable at 420 and mg is 1350
Terry Martin
Well-Known Member
I use brs soda ash. I dose about 225 ml and that keeps alk in the 8.5 +/- .5 range. I have to dose more ca, about 250 ml a day to keep in your range 400-450. Mg I don't test much but has always been 1400+ on Triton.
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reefer125g
Non-member
It just seems funny to be consuming so much Alk but not CA . Always thought it should be in equal parts
Terry Martin
Well-Known Member
I've been dosing 2-part for five years and never had equal rates either.
dz6t
Acro Garden, BRS Sponsor
That is due to calcium test kits are less sensitive. All calcium test kits have big margins of error and should not be used as a guidance for dosing. That includes Triden.
Alk test kits such as Salifert, Red sea, excluding API are sensitive enough to guide dosing. That is where the two parts system really works, just test Alk and dose equal volume of Alk and Calcium solution.
Stanley Wong
Well-Known Member
In one of the Randy Holmes-Farley article it has mentioned the calcium & carbonate are not consumed equally due to impurities. Plus the percentage of change in Calcium is much smaller than carbonate.
dz6t
Acro Garden, BRS Sponsor
The confusion comes in the unit of calcium (ppm) and Alk (dkh etc).
If one measure calcium and carbonate (major part of alkalinity) in ppm, they do not get consumed at the same ppm due to they have different molecular weight.
But when coral forms its skeleton in calcium carbonate, it is one calcium binds to one carbonate.
If one wants to go into academic exercise, Indeed it is not 100% at 1:1 ratio. Because what all the hobby grade test kits measuring is the total alkalinity, not the concentration of carbonate. Even more confusing is that alkalinity is not a single element like calcium, it is the buffering capacity of the water, which affected by many different elements.
If we want to go deeper, many cans of worms will be opened and it will make people so confused.
But the difference is so small that it is beyond hobby grade test kits can measure. Also the small difference is not important nor applicable to this hobby.
The bottom line is by dosing commercial calcium and alkalinity solutions at 1:1 volume ratio, you will be fine. Monitor Alkalinity often and spot check your calcium level once a while. Or even better, use a calcium reactor with Reborn reactor media, only check the Alk level and forget about all these dosing mess.
If one measure calcium and carbonate (major part of alkalinity) in ppm, they do not get consumed at the same ppm due to they have different molecular weight.
But when coral forms its skeleton in calcium carbonate, it is one calcium binds to one carbonate.
If one wants to go into academic exercise, Indeed it is not 100% at 1:1 ratio. Because what all the hobby grade test kits measuring is the total alkalinity, not the concentration of carbonate. Even more confusing is that alkalinity is not a single element like calcium, it is the buffering capacity of the water, which affected by many different elements.
If we want to go deeper, many cans of worms will be opened and it will make people so confused.
But the difference is so small that it is beyond hobby grade test kits can measure. Also the small difference is not important nor applicable to this hobby.
The bottom line is by dosing commercial calcium and alkalinity solutions at 1:1 volume ratio, you will be fine. Monitor Alkalinity often and spot check your calcium level once a while. Or even better, use a calcium reactor with Reborn reactor media, only check the Alk level and forget about all these dosing mess.
Last edited:
Greg Hiller
BRS Moderator
>The bottom line is by dosing commercial calcium and alkalinity solutions at 1:1 volume ratio, you will be fine. Monitor Alkalinity often and spot check your calcium level once a while. Or even better, use a calcium reactor with Reborn reactor media, only check the Alk level and forget about all these dosing mess.<
I agree, and don't forget to do a water change every-so-often to pull things back to a normal range for most things. If you dose two-part solutions only, and dose a lot of them you will have an increasing salinity. I also agree that calcium reactors are the way to go for a big tank or one with lots of fast growing stuff. Problem at the moment is that it's nearly impossible to get Reborn or most other calcium reactor substrates. No flights from the Pacific = nothing coming from the Pacific islands.
I agree, and don't forget to do a water change every-so-often to pull things back to a normal range for most things. If you dose two-part solutions only, and dose a lot of them you will have an increasing salinity. I also agree that calcium reactors are the way to go for a big tank or one with lots of fast growing stuff. Problem at the moment is that it's nearly impossible to get Reborn or most other calcium reactor substrates. No flights from the Pacific = nothing coming from the Pacific islands.
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