Dosing Mg

[Reef Pilot]

My Mg used to always be up in the 1400 range, but has been dropping, and getting a little low now, in the 1200 range. I have never dosed Mg, but may have to start.

However, I don't have a 3rd dosing pump. Does manual dosing work with MG or is that too erratic with adverse effects on the corals? Or could I add some Mg mix to my Ca dosing container and do both at the same time?

I have had a bit of an algae problem after I combined my tanks into one sump, and my P04 was up a bit for a while. And I vaguely recall reading somewhere that low Mg can also contribute to algae. Is that true?

[tang daddy]

You can safely raise 100ppm of mg daily, for your size system it could mean lots. I had to raise mine over 400 ppm and it took me 2 weeks and tons of mg.

You could build a make shift drip system out of an old milk jug or anything that holds water, then calculate how much mg is needed to your total water in your system, and using gravity syphon with a irrigation nossel drip it in over a week.

Eg. 2 cups of mg to 1g of ro, drip it at 1 drop per second. Test it after you have finished adding the mg and see where it's at then you can mix up another batch.

Surprisingly most people don't have to dose it, I am dosing 180 ml for my 90g of water volume daily. That's alot considering of small water volume... I couldn't keep up and had to get a doser.

[Reef Pilot]

Originally Posted by tang daddy

Surprisingly most people don't have to dose it, I am dosing 180 ml for my 90g of water volume daily. That's alot considering of small water volume... I couldn't keep up and had to get a doser.

Yeah, that's a lot, alright. I have never had to dose Mg so far, and hopefully won't have to do that much. That's why I would like to start off with manual dosing. And even try combining it with my Ca dosing, if that works. I really don't want to get another doser...

[Bblinks]

Even with my calcium reactor filled with 20% magnesium I still find myself having to add it manually. Like T-diddy said, 100 ppm per day is the maximum. I have dosed up to 2.5 gallons at a time without any problems and that only raised my mag from 1250 to 1320.

[tang daddy]

Originally Posted by Bblinks

Even with my calcium reactor filled with 20% magnesium I still find myself having to add it manually. Like T-diddy said, 100 ppm per day is the maximum. I have dosed up to 2.5 gallons at a time without any problems and that only raised my mag from 1250 to 1320.

T-diddy dat new.... I like T-Dot!

[Reef Pilot]

My Mg has been running about 1260 ppm lately (used to be around 1400), so decided to start raising it with manual dosing. Yesterday I added 125 grams of Seachem Reef Advantage Magnesium to a 230 gal water vol. This is only 1/2 the maximum dose they recommend for one day. And to raise it all the way to 1350, their dosing calculator says I need to add about 8 or 900 grams, which seems like a lot to me.

So today, I test my Mg again to see what effect it had. And to my surprise, my Mg is now higher than 1500, which is the max I could test for with my Salifert test kit!! WTF!!! It should only have gone up by maybe 10 - 15 ppm according to their instructions.

I reread and reread the instructions, and did more research on the web, but can't figure out what I did wrong.

I also tested my alk (8 dKH) and Ca (400 ppm) and it did not change much from yesterday. And everything in my tank(s) look normal.

I will test again tomorrow. But any ideas what is going on here??

[e46er]

Strange maybe your initial test was off?
I have used lots of seachem products (mainly my old planted tank) but a few for SW and Their magnesium is the single only product I haven't liked.
My mg was low and over like 2 weeks I had dumped the entire 600 g tub in with no increase.
I got some mag. From little silver max and his product rasied it exactly what he said it would with an online calculator.

My guess is your original testing was off

[Reef Pilot]

Tested again today, and it came in at 1290 which makes more sense. My guess is that yesterday I may not have pulled in the test solution to the top mark in the syringe. I have tested Mg many times before, and never had a bad test, so a little strange that it would happen right after adding Mg.

Anyway, will add more MG today, and keep tracking it.

[Proteus]

I had the same issue with seachem mag and there calculator. I ended up cutting the recommended dose in half and making sure the tanks water mixed for 2 hours before retest

[Reef Pilot]

Yeah, it definitely doesn't mix easily. Just added another 125 grams this morning, and will test again tomorrow to see if it brings up my Mg. I bought the 600 gram size, so I might as well use it up.