Orion January 30, 2014 Share January 30, 2014 Just started 2-part dosing 4 days ago, and I am still getting things dialed in. Is it common for a tank to have to dose more calcium than alkalinity (or vice versa), or should they be consumed at roughly the same rate? So far I am finding that I am having to dose 10-15ml more calcium per day vs. alkalinity. Current Parameters - Calcium 430 Alkalinity 7.8 Magnesium 1350 Link to comment Share on other sites More sharing options...
AlanM January 30, 2014 Share January 30, 2014 MIne never uses up calcium, but does use quite a bit of alk. I ended up dosing calcium by hand once per week because the number just doesn't drop that much, but at the moment I need around 22ml of BRS 2-part alk solution each day to keep up with consumption to keep it at 9 dkh. I think most people dose more alk solution than calcium, not the opposite. Link to comment Share on other sites More sharing options...
sen5241b January 30, 2014 Share January 30, 2014 Just started 2-part dosing 4 days ago, and I am still getting things dialed in. Is it common for a tank to have to dose more calcium than alkalinity (or vice versa), or should they be consumed at roughly the same rate? So far I am finding that I am having to dose 10-15ml more calcium per day vs. alkalinity. Current Parameters - Calcium 430 Alkalinity 7.8 Magnesium 1350 How big is the tank? Link to comment Share on other sites More sharing options...
Cliff Puckstable January 30, 2014 Share January 30, 2014 I have to dose more than 2x the amount of Ca than Alk. I keep my alk at 7dkh. Ca is 420. Link to comment Share on other sites More sharing options...
Origami January 30, 2014 Share January 30, 2014 To boil it down, calcium is not consumed faster than alkalinity. The ratio of consumption is relatively fixed. However, because of the way most 2-part recipes are mixed, you will use twice as much (by volume) of the Alk part as compared to the calcium part. This two-to-one may confuse one into thinking that one is being consumed faster, when in fact, it's perfectly normal. It's like the caffeine in a shot of express versus a cup of coffee. It may be the same, even though the volume of expresso is a lot less. This link goes to a seminal write up of DIY two-part authored by Randy Holmes-Farley. If you've never read it, do so as it is very informative and will give you understanding that you may not have already. "Recipe #1" refers to dosing calcium using an aqueous mixture of calcium chloride. "Recipe #2" refers to dosing alkalinity using an aqueous mixture of either sodium bicarbonate (aka baking soda) or sodium carbonate (aka soda ash, or baked baking soda). The desired ion concentration is set by the recipe for the solution. Obviously this can change by altering the recipe. Anyway, as you can see in Table 1, the standard dosing protocol calls for twice (by volume) as much of the alkalinity solution to be dosed than the calcium part. There's a reason for this, but that's not germane, so I won't go there. But simple ratios are, well, simple. The hard skeleton of most corals is composed largely of calcium carbonate. This calcium carbonate comes from combining the calcium from Recipe #1 with the carbonate ion species delivered in Recipe #2. The ratio of the combination - that is, the molecular formula for calcium carbonate - is fixed (it's CaCO3). Now, while there are some minor deviations from the predicted ratio due to the availability of ions like Magnesium, Strontium, and Barium, for the most part calcium and alkalinity are combined in a ratio that is very close to 1 milliequivalent per liter for every 20 ppm of calcium. If you use dKH as your unit of alkalinity measure, that's 2.8 dKH of alkalinity consumed for every 20 ppm of calcium consumed. There are a few, uncommon reasons for this ratio to substantially deviate, but they complicate the understanding offered by this simple entry in my "reef aquarium facts" as I like to call them. Link to comment Share on other sites More sharing options...
morgan175 January 30, 2014 Share January 30, 2014 Ok I'm butting in sorry. What does magnesium have to do with balancing both your calcium and alkalinity. I have read where if magnesium is not high enough the two will not raise. Is this true. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
BowieReefer84 January 30, 2014 Share January 30, 2014 Using b-Ionic the ratio is 1:1. You should not be using more than one than the other. If you are mixing DIy what Tom said... Link to comment Share on other sites More sharing options...
YHSublime January 30, 2014 Share January 30, 2014 This two-to-one may confuse one into thinking that one is being consumed faster, when in fact, it's perfectly normal. It's like the caffeine in a shot of express versus a cup of coffee. It may be the same, even though the volume of expresso is a lot less. Tom, that is a wonderful analogy. Thanks! Link to comment Share on other sites More sharing options...
Orion January 30, 2014 Author Share January 30, 2014 Thank you very much Tom, very informative. It looks like 2:1 for me using the BRS 2-part, and this would make total sense. Link to comment Share on other sites More sharing options...
Orion January 30, 2014 Author Share January 30, 2014 (edited) Ok I'm butting in sorry. What does magnesium have to do with balancing both your calcium and alkalinity. I have read where if magnesium is not high enough the two will not raise. Is this true. Sent from my iPhone using Tapatalk I was just simply stating what my current parameters were. Calcium, Alkalinity, and Magnesium. It is true if you do not keep your Magnesium in check that you will have issues maintaining Calcium and Alk. Edited January 30, 2014 by Orion Link to comment Share on other sites More sharing options...
Origami January 30, 2014 Share January 30, 2014 Ok I'm butting in sorry. What does magnesium have to do with balancing both your calcium and alkalinity. I have read where if magnesium is not high enough the two will not raise. Is this true. Yes, it's true. The magnesium in the water interferes with the spontaneous formation ("abiotic precipitation") of calcium carbonate when the sea water is holding very high (super-saturated) levels of calcium and carbonate species ions. You see, there's a concentration beyond which, under normal circumstances, you get combining of the two ions to form this limestone (calcium carbonate). You may see it, for example on heaters, pump bodies, etc. because the heat of these lowers the Ksp (solubility constant) and forces precipitation. Anyway, levels of calcium and carbonate in sea water is well beyond the normal level of saturation. That is, it's "super saturated." Without the magnesium acting to interfere with the process, it would snow calcium carbonate precipitate in your aquarium. This snow basically draws down the calcium and alkalinity concentrations until "saturation" is reached. These are levels that are much lower than you see in normal sea water. If you try to add more calcium or alkalinity in this scenario, it just falls out as new precipitate and your alk levels don't rise appreciably. In fact, you will see a parallel drop in calcium as your trying to push up the alk. In order to get the water to hold more of the calcium and alkalinity than it would requires raising the magnesium level. To gain an added appreciation of this, take a look at the periodic table sometime and note that both calcium and magnesium are both in the same column. That is, they're both in what we call the "alkaline metals" column and, in ionic form, both are bivalent cations. Thus, from a bonding perspective, they are somewhat similar. It's this property that gives magnesium its ability to interfere so effectively. Link to comment Share on other sites More sharing options...
morgan175 January 30, 2014 Share January 30, 2014 Thank you. My Red Sea test came in today for magnesium and I ran a test it was 800 ppm. Went right out only thing I could find was fluval magnesium. No wonder calcium was staying at 350 and not going up. Thank you again. I read only to raise 100 ppm per day so we shall see. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
zygote2k January 31, 2014 Share January 31, 2014 Thank you. My Red Sea test came in today for magnesium and I ran a test it was 800 ppm. Went right out only thing I could find was fluval magnesium. No wonder calcium was staying at 350 and not going up. Thank you again. I read only to raise 100 ppm per day so we shall see. Sent from my iPhone using Tapatalk make your own Mg from Home Depot Mg Chloride Ice melter and CVS Mg Sulfate (Epsom salts). Depending on the size of your tank, you'll need quite a lot of Mg to raise it from 800 to 1500. Gallons.... Link to comment Share on other sites More sharing options...
zygote2k January 31, 2014 Share January 31, 2014 (edited) Also- Every tank does not need to be dosed with 2 part. This is a common misconception around here. You only start a dosing plan when your tank cannot maintain parameters through regular water changes. Another thing is that magic numbers aren't always correct and shouldn't be chased- they're just rough guidelines based upon NSW. I find that more tanks can't grow corals because of Nitrate and Phosphate issues rather than 2 part issues.... Edited January 31, 2014 by zygote2k Link to comment Share on other sites More sharing options...
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