A recent Alkalinty overdose got me thinking about the Alkalinty to Calcium dosing ratios. Should the amount that one is dosing of each be close to equal? For example I use the BRS new 2 part if I am dosing 100 ml of Alk should the Ca be approximately the same amount. I am testing and the levels are staying pretty consistent but I dose a lot more Ca than the Alk.
Alk Ca two part dosing ratio?
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GoVols
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Your good...
I've only used one product that came out to even doses.
Just dose like @Potatohead said, and keep both where you like.
beaslbob
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Yes.
The dr randy holmes-farley improved diy two part system is designed to dose equal parts of the calcium and alk solutions when KH drops down. And after using up a gallon of the calcium and alk solutions you add 300ml of the magnesium solution.
Additionally, the instructions specifically recommend you resist the temptation to measure cal along with alk and make adjustments. IMHO sure every few months or so make adjustments but basically you test alk and dose cal and alk equally when alk is down.
my .02
Martin Kuhn
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Randy‘s recipe is designed in a way that you dose the same amount of Alk and Ca solution „IF“ (and Only if....) your tank consumes Alk vs Ca in a balanced way.
As you dose more of the Ca solution than Alk and you keep your levels, this is perfect.
Each tank is different. Your tank consumes more Ca than Alk for whatever reason. So your dosing should do exactly the same.
If you wouldn’t, then either your tanks Alk would get too high or your Ca too low over time.
I call this „consumption orientated dosing“
Randy also states that cal and alk fall evenly. Magnesium also as the same relative rate.
Thus three part (two part) can be and is designed to be dosed evenly.
That’s why you really only need to test alk regularly.
An excess of either of the other two is not a problem according to RF either and only extreme of them could be problematic.
So ratios don’t matter as it’s availablity you need be concerned with. (Like the current and reoccurring nutrient ratio thing)
Martin Kuhn
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Sorry. Based on knowledge of lots of reef tanks here in Europe I disagree.
Although balanced dosing is very nice, works in a lot of tanks and sounds super easy especially to newbies,
It is not always the best option
There are several reasons for that (unbalanced consumption, influence of salt mixture used, etc). A possible result is eg Ca overdosing, or Mg under/overdosing for 3 part recipes.
Measuring the big three (whereof Mg requires measuring only sometimes as it decreases as slow)
+ dosing all 3 according their consumption
Is clearly the way to go.
Also having identical doses of Ca vs Alk solutions is no real requirement in times where everybody uses peristaltic pumps as dosers . Just adjust them differently.
I mix my brs 2 part as per their instructions and I use about twice as much alk than cal. Been stable for about a year that way with no weird precipitation or anything. The equal parts thing always confused me and made setting up my doser harder then it had to be
Randy Holmes-Farley
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If you are very careful about measurements and dosing amounts, you will find that unless water changes are messing with the demand ratio (very common), the ratio of my DIY (e.g., BRS) will be quite close to 1:1 unless you use a sulfur denitrator.
Folks who say it is not are often not measuring long enough or carefully enough ( e.g., assuming two dosing pumps match, measuring over only a few days, etc.). Some who have claimed it is not 1:1 for their tank have found, when checking carefully, that it is close to 1:1.
FWIW, the smaller your daily demand, the more likely is that it deviates from 1:1 because the known very minor deviations become more significant (e.g., changes in nitrate level impact alk and not calcium, etc.).
Also, obviously, any additions of calcium or alk in other ways will alter the apparent demand ratio. Topping off with tap water, is a common cause.
FWIW, here's a detailed discussion of this issue:
When Do Calcium and Alkalinity Demand Not Exactly Balance? by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2004-12/rhf/index.htm
Folks who say it is not are often not measuring long enough or carefully enough ( e.g., assuming two dosing pumps match, measuring over only a few days, etc.). Some who have claimed it is not 1:1 for their tank have found, when checking carefully, that it is close to 1:1.
FWIW, the smaller your daily demand, the more likely is that it deviates from 1:1 because the known very minor deviations become more significant (e.g., changes in nitrate level impact alk and not calcium, etc.).
Also, obviously, any additions of calcium or alk in other ways will alter the apparent demand ratio. Topping off with tap water, is a common cause.
FWIW, here's a detailed discussion of this issue:
When Do Calcium and Alkalinity Demand Not Exactly Balance? by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2004-12/rhf/index.htm
Ross Petersen
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Hi Randy,
I'm starting to dose a reef tank in our high school chemistry lab.
Reading through your updated 2-part protocol and this thread. Can you clarify this sentence for me if you have the time: "When calcification takes place, two moles of alkalinity are lost for every one mole of calcium."
I'm trying to visualize a few balanced reactions (e.g., Ca2+ CO3 2- ---> CaCO3) to get at the stoichiometry. Invariably overlooking this one!
Sincerely,
Ross
animatedcorals
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I always dose about 50ml of Alk but noticed my calcium doesn’t change till every two days. It’s strange because it drops about 100ml in two days but on the first day it doesn’t change then all of a sudden it’ll drop 100ml worth. Very strange
