2 Part Dosing

[Wretch]

Originally Posted by mark

RHF recipe

Thanks for the info.

[Wretch]

Ok got my doser setup to dose Calcium and Alkalinity but have a question about magnesium. J&L sell Magnesium Chloride or Magnesium Chloride Flake. The two are the same thing just in different form, so why is here a price difference between the two? Do you have to weigh the flake? or can it be measured? Does the flake dissolve as well as the powder? Is the price difference worth it? Thanks all.

[hillegom]

When you get the mag chloride, get some mag sulphate (epsom salt) from costco. Its the cheapest. Mix as in the given recipe above.
Sorry, I don't know the difference betw. the powder and the flake.

[Myka]

Originally Posted by Randy Holmes-Farley

A certain mixture of magnesium chloride and magnesium sulfate has no net effect on seawater's major anions (chloride and sulfate). All that is necessary for such a recipe is to add these two ingredients in such a ratio that they add chloride and sulfate in the ratio naturally present in seawater (which is 7.1 to 1 on a weight basis and 9.6 to 1 on a per ion basis).

To perfect such a recipe, it's imperative to know the amounts of sulfate in Epsom salts (39%), the amount of chloride in magnesium chloride hexahydrate (34.9%), and their bulk densities, because most aquarists will use a volume based measurement (1.05 g/cm3 for Epsom salts and 0.85 g/cm3 for magnesium chloride hexahydrate solids). Taking all these factors into account, the desired volume ratio is 10:1, MAG flake to Epsom salts, as a supplement; for instance, 10 cups MAG flake and 1 cup Epsom salts.

http://reefkeeping.com/issues/2006-07/rhf/index.php

RHF wrote this article when calcium reactors were THE thing. 2-part dosing is more common now though, and we add a lot more chloride ions through calcium choride, so a better version for 2-part particularly if you are dosing calcium chloride heavily is 5:3 chloride to sulfate to make up for all the chloride we're adding via 2-part.

[hillegom]

I use this recipe from Randy Holmes:

3. Using both Epsom salts and MAG flake, dissolve 7¼ cups MAG flake and ¾ cup Epsom salts in one gallon of water, and use that to supplement magnesium in amounts determined using this linked online calculator, with the entry "Randy's Recipes 1 and 2 Versions A and B," and ignore for this purpose what those designations mean. This recipe is preferred, but its advantage over recipe #2 is minimal in most cases.

Which is derived from:
http://reefkeeping.com/issues/2006-07/rhf/

[reefwars]

which like mindy said is 10yrs old now

[reefwars]

oh and flake is most likely dihydrate fwiw

[gregzz4]

Originally Posted by hillegom

I use this recipe from Randy Holmes:

3. Using both Epsom salts and MAG flake, dissolve 7¼ cups MAG flake and ¾ cup Epsom salts in one gallon of water

Deitmar, why are you using the recipe #1 Part 3B measurements ?
I use the Part 3A dosing with 5 cups and 3 cups

An Improved Do-it-Yourself Two-Part
Calcium and Alkalinity Supplement System

[hillegom]

I don't know Greg, I have been using that for a long time. Whats wrong with that recipe?