how often do you dose magnesium?

[teddyb]

I bought the two part system from bulk reef supply and it has been working great. My question is how often do you guys dose magnesium? Do you dose it as often as CA and Alk?

On the website it says to dump the whole 20 oz of Mag in my tank when I'm completely out of CA and Alk, this does not sound right to me. Ive done numerous water changes and I'm not even halfway through my one gallon mixture of CA and Alk. Does the level of Magnesium drop as quickly as calcium and alkalinity do?

Maybe I should just get a Mag test kit. 8)

Any advice would be greatly appreciated. Thanks in advance my fellow RC'ers.

 

[Reeefer]

Mag does not deplete as fast, but I would add back in daily. The dose is just going to be a lot smaller than your Ca or Alk.

 

[aleaksreef713]

If your Mag was real low then those are the directions, I am dealing with low mag right now and the directions on the Kent Mag bottle are crazy, 1ml per gallon.... Imagine if you had a 250....

My mag is at 1100, so im gettin back up slowly but surely, if anyone else has any advice, please let us know....

 

[jimsplace]

I wouldn't dose anything without testing, if you don't test you don't know. As stated above, mag does deplete slower. When it gets low, you will have a harder time keeping calc and alk numbers up also. I let mine get low, got it raised back up and now dose once a week and test about once a month to make sure my number is around 1400. BRS is a good choice for the mag c & s. You will use lots of mag to raise your numbers, also watch your salinaty as the large addition of mag may cause it to rise.

 

[Randy Holmes-Farley]

I wouldn't dose anything without testing

Well, I think this situation is different. Most people would use a commercial two part calcium and alkalinity supplement (like B-ionic) without testing for magnesium, and this is no different, except it comes in 3 parts.

I designed the Recipe that Bulk Reef uses to balance the need for magnesium with the calcium and alkalinity consumed. So magnesium should not change too much over time when dosed as directed.

If you choose to spread out the magnesium dose during the entire time the jug of calcium and alkalinity is used, that is fine, but unless the tank is smaller, the change in magnesium is not going to be all that large even with all at once dosing.

FWIW, adding 20 oz of the magnesium supplement to 100 gallons of water only raises magnesium by 73 ppm, or about 6%. That is the same percent drop as allowing alk to drop from 8 to 7.5 dKH, and then boosting it.

If the tank is smaller than 100 gallons, splitting the dose in half and dosing twice during the gallon jug use is a good plan, and if it is a very small tank, frequent dosing may be useful.