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How Much To Dose: Notes On Dosing New Solutions (1 Viewer)

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Cody

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Like most members of our community, I started off with a saltwater fish-only tank. However, as seasoned veterans know, there is no such things as a fish-only tank; just reef tanks with no corals yet. You nervously get your first softie, and to much surprise, you can make that mushroom coral thrive. Then you try an LPS, have the same success, and decide to move onto SPS. However, somewhere along the way, the water-changes just don't keep up with the demands of the corals. Looks like it's time to pick up some peristaltic (dosing) pumps, some solution, and start dosing. But then the questions arises: how much do I dose?





With Dosing Calculator:

There are quite a few brands that have their own dosing calculators, and I would recommend those over a brand without one any day. Accuracy in dosing is vital to maintaining control over your tank parameters. My advice to anyone starting to dose with a brand that uses calculators would be to error on the side of safety. The side of safety is in regards to the water volume and to what degree you calculate total water volume. Let me demonstrate:



Let's use a standard dimension 180 gallon aquarium for an example. A standard 180 has the external dimensions of 72”x24”x24”. Given that a gallon is equivalent to 231 cubic inches, our actual amount of gallons is 179.53. No problem. Let's take out the thickness of the glass. Assuming the tank has 1/2” thick glass, now we are down to 166.13 gallons (That's a 7.5% reduction of water volume, just by subtracting glass). Not too bad though; still in the same ballpark. But we also have to consider the fact that we don't fill the tank to the brim, and normally leave somewhere in the ballpark of 1.5” at the top without water. Now, we are down to 159.01 gallons (that's already roughly 12% less than the advertised water volume, which is significant). Let's take a conservative guess that our sand and rocks take 20% of our remaining water volume out. Now we are down to 127.21 gallons. That's roughly 30% less than the advertised 180 gallon water volume.



I said that to say this: Be conservative. Calculate that your tank has less water volume than you think it does, and be mindful of the way you calculate water volume. If you think your total water volume, sump included, is 100 gallons, then dose for 70-75 gallons at first, and see how it effects your parameters. Slow and steady is the name of the game when it comes to reef tank parameters, and a soft change is always preferable to a hard change. I just demonstrated how a 180 gallon tank has roughly 12% less water volume than you thought, and that's before we take out rocks, sand, corals, fish, etc. As far as adding the volume of water in the sump, this is easy. Multiply the length, width, and height of the water in each chamber, then divide by 231 to find how many gallons of water are in each chamber of the sump. Sumps are rarely significantly filled with rocks, sand, etc to the degree that our display tanks are filled, so the simple inside diameters of each chamber can be very telling. Add that to what you think the water volume in your main tank, and you have a rough estimate of your total water volume.





Without Dosing Calculator:



For those that are dosing a solution without a dosing calculator, here's how you can easily figure out how much to dose.




  1. Measure out exactly 1 gallon or RODI water in a container (RODI should measure 0 ppm for the parameters that we are testing for, assuming your TDS is 0)
  2. Add 1mL of the dosing solution
  3. Stir the container water/solution for a minute
  4. Test for that parameter of the 1 gallon container after dosing 1 mL of solution (The results have to be in ppm for this to work, and if they're not, then google is your friend. Convert your test results to ppm)
  5. Record these results
  6. Use this equation to figure out how much to dose: ( (X) Amount ppm that you want raise total tank water volume / (Y) how much 1mL raised the RODI solution)* Total tank water volume (Z) = How much to dose (Q)
  7. Here's the basic equation: (X/Y)*Z = Q





Let's illustrate with an example.



I am wanting to dose a new Calcium Solution. I figure out that if I add 1 mL of Calcium Solution to 1 gallon of RODI water, that it raised it from 0 ppm to 40 ppm. I have roughly 100 gallons of water volume in my system and I want to raise it from 410 ppm to 430 ppm. How much do I dose?



Well, let's figure out the variables for the equation that I presented.





(X) Amount ppm that you want to raise total tank water volume = 20 ppm

(Y) How much mL to raise 1 gallon of water = 40 ppm

(Z) Total tank volume = 100 gallons

(Q) = How much do I dose (mL)?



Here is the equation that I presented earlier:



(X/Y)*Z = Q





(20/40)*100 = Q

(.5)*100 = Q

50 = Q



I need to dose 50 mL of Calcium Solution to raise my parameters from 410ppm to 430 ppm Calcium.
 
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Luman01

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That’s pretty cool! Guess there was an actual use for highschool math classes after all 😂😂 But could there or is there something similar if you are using kalkwasser?
 
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Cody

Cody

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That’s pretty cool! Guess there was an actual use for highschool math classes after all 😂😂 But could there or is there something similar if you are using kalkwasser?
You'll find in life that from chemistry calculations to arguments, a lot of basics boil down to algebra. My minor was Philosophy and we studied logical notation, which is the algebraic notation of statements and arguments. There are many practical applications of math and logic on a daily basis and they will serve you well to keep them dear to your heart.

As far as Kalkwasser is concerned, until you know that your water in the reactor is 100% saturated, you can't know for sure, and even then, be conservative. The best way to dose kalk is to monitor the results. Check your parameters often once you put it in play. I can expand upon this in another article, but not today. It would be the idiot's version of how to use the stuff. Long story short, an overdose will kill everything in your tank. However, if used correctly, it's god's gift to reefing.
 
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