BRS 2 Part Cost Analysis

[Ryan S]

http://spreadsheets.google.com/ccc?key=0AtSIqMfJBJjxdGJJeXpRYVpLQU56LWxLM0M3QTB5Y0E&hl=en

 

I've been working on this spreadsheet for a little while. I'd like to add Calcium Reactor + Kalk Reactor as a side by side comparison when I get the time. Unless one of you has the time to help me finish it?

 

I've also attached the MS Excel version.

 

-Ryan

Dosing Chart.xls

[Origami]

Here's a *simple* ion-for-ion analysis using BRS prices available today. Let's start with two-part:

 

Calcium Chloride (dihydrate):

Calcium Chloride is what you use to supplement calcium. CaCl2*2H2O lists at $10.99 for 3.5 pounds. At 147.014 grams per mole, that's $10.99 for 10.8 moles of the stuff. Or, $1.02 per mole of usable calcium supplemented.

 

Sodium Bicarbonate:

Sodium bicarbonate is what you use to supplement alkalinity. NaHCO3 lists at 10.99 for 4 pounds. At 84.01 grams per mole, that's $10.99 for 21.6 moles, or $0.37 per mole. However, you need two units of bicarbonate for every unit of calcium, so this brings the price to $0.74 per 2 moles of bicarbonate supplemented.

 

Material cost of two-part, neglecting delivery means is therefore ($1.02 + $0.74 = ) $1.76 per mole of calcium carbonate skeleton.

 

Let's now look at Kalkwasser, or Calcium hydroxide.

 

Calcium Hydroxide:

Calcium hydroxide is a balanced additive. Through a reaction with carbon dioxide (CO2) that is available in the water, it adds calcium and bicarbonate (HCO3-) in the required proportions. In other words, you get two units of bicarbonate for every unit of calcium delivered. So it's sufficient to calculate the cost per mole of that one material to cover both needs. BRS lists Ca(OH2) today at $7.99 for 2.25 pounds. At 74.093 grams per mole, it costs $0.58 per mole of calcium carbonate skeleton.

 

Conclusion:

Ion-for-ion, kalkwasser compares very favorably to two-part in operating costs. Quantitatively, kalk is approximately 1/3 the cost of two-part (ion-for-ion).

($0.58 / $1.76) ~ 1/3

 

Caveats:

This calculation uses BRS prices for their pharmaceutical grade materials. You can reduce the cost of any of these components with "kitchen" substitutions. For example, in my mind, there's no reason to not use Arm & Hammer baking soda rather than pharma-grade sodium bicarbonate. On Amazon (today), A&H costs $4.49 for 4 pounds, or $0.30 per 2 moles. This alone can reduce the cost of two-part to $1.32 per mole. Still more than Kalk, but a savings nonetheless. Additional (and even greater) savings may be gained if you find an acceptable grade of commercial ice melt that is relatively free of unwanted impurities - keeping in mind (of course) that most grades of ice melt are calcium chloride HEXAhydrate CaCl2*6H2O (which is 219.08 grams per mole, and therefore only 67% as dense as the dihydrate material) which means you'll use about 50% more of it for the same calcium boost. The same applies for calcium hydroxide, though, which can be obtained in bulk quantities as Mississippi lime, for example.

 

Another fact that might help put this in context:

Assuming a coral skeleton is 100% calcium carbonate (and it's not - it varies typically between 85% and 98% depending upon the coral and the environment), one mole of calcium consumed plus two moles of bicarbonate consumed are required to produce 100 grams of coral skeleton since calcium carbonate - Ca(CO3)2 - weighs 100.09 grams per mole. Depending upon your dosing method, this growth can cost you $1.76 (using two-part) or $0.58 (using kalk).