Interesting Magnesium Observation

[Myka]

As many of you know, I have about 30 Bangaii babies in a container in my 33g reef tank. They are causing a HUGE bioload, and have caused a massive hair algae bloom. My water column tests just a trace of Nitrate and just a trace of Phosphates, but it's obvious there's more in there. I added a PhosBan Reactor and put 2" of RowaPhos in the chamber, and noticed no difference after a week. So I figured what the heck, I'll try the ole raise the Magnesium trick. Up until this time I've kept my Magnesium in the 1350-1400 ppm range. So I've been doing waterchanges with 1550 ppm Magnesium, raised by Epsom salts. I honestly don't know what my tank is at right now because I haven't tested it, but I've done two 30% waterchanges with raised Magnesium. It really shouldn't be much higher than about 1450-1475 ppm. The hair algae has become significantly stunted.

So that's all fine and dandy, but here's what I've noticed. I always have a 5g bucket of saltwater mixing for waterchanges, but mostly because I need saltwater every couple of days to make new batches of baby brine shrimp. Now, usually I add the Epsom salts to raise the Magnesium just a couple hours before I do the waterchange, and use "normal" SW for my BBS. Well, three times I have used the SW with elevated Magnesium. In all three batches of BBS (using the same container of eggs) I have had VERY poor hatch rates. I mean I use 1/4 tsp in a 2L pop bottle, and normally when I syringe the BBS out there are so many in the syringe that it appears pink-orange and you can't even see through it. When I use the SW with elevated Magnesium you have to really look to notice there are any BBS in there at all.

So...is it the elevated Magnesium that's causing this? Or a sensitivity to the sulphates in Epsom salts?

AND...if BBS are sensitive to this (for whatever reason) what is it doing to my reef?

Either way, I have some SeaChem Magnesium on the way!

[calkrog]

seachem wont do the trick. you need Kent tech-M. i know from experience having battled bryopsis for a while. and if it is regular hair algea you are talking about elevating your mag will not do a thing about it.

[Pan]

Magnesium always makes up for poor water quality J/k

[christyf5]

I vote for the elevated sulphates. Epsom salts have been reported to be a good way of a "one time" increase in magnesium levels but repeatedly doing waterchanges containing epsom salts increases your sulphate concentration which isn't exported. I would imagine its having an effect on the more primitive critters which don't have the systems to deal with it.

[littlesilvermax]

I also vote for the elevated sulphates, although I don't really know.

[Sebae again]

I've heard of people increasing their mg to those levels to kill flatworms so maybe it has the same effect on BBS. Since I've added a CPR hang on fuge to my tank,I've never had hair algae in the tank. It only grows in the fuge for some strange reason and this has been with 2 tanks over a 3 year period supporting a large fish load.

[Myka]

Originally Posted by 'Ol Nobodaddy

Magnesium always makes up for poor water quality J/k

Oh for sure the water quality is poor! There are 30 Bangaii babies, 2 adult Bangaiis, a Percula Clown, and a Hector's Goby in a 33g reef with no sump or fuge!!

I've found out that having baby Bangers in the reef system is a really BAD idea. So I'm working on making a Banger grow out system completely separate of my reef. I also just got a 75g cube tank that the 33g is being upgraded to, so the hair algae really isn't an issue. At least it's keeping the phosphates and nitrates out of the water column! My corals are happy, so I don't care. It just looks ugly, so I tried out the PhosBan Reactor. I've never tried the Magnesium method, so I figured I'd give it a shot. Right now it's really just an experiment...

I was going to throw out the BBS, but I got lazy and just left them. That bottle is now about 52 hours old, and even though there was squat for BBS in there this morning it is LOADED now. So I guess it (whatever "it" is) is causing a delayed hatch rate. Odd...

I know Kent Tech M has nitrates in it, so that's why I'm choosing to use the SeaChem as SeaChem's doesn't have nitrates. The elevated Magnesium is just an experiment, I really don't care if it doesn't work, but I still need a good Magnesium supplement since my salt is a tad low. I don't understand why calkrog said the SeaChem won't work as it has a slightly higher Magnesium concentration than the Kent does...

[calkrog]

seachem does not contain the epsom salts, which contain mag sulfate, which is what kills the bryopsis. seachem contains mag chloride. but kent tech M does mag sulfate. I experimented for a while, started with seachem, it did not work, and after reading the whole 200pg thread on RC i read that only people using epsom and tech-m were successfull. so i tried tech m, and it works like a charm. but only on bryopsis, if you have regular hair algae it does nothing.

if you have nothing better to do... read away. http://reefcentral.com/forums/showth...readid=1113109

[Snappy]

Magnesium dosing should contain a balance of chloride & sulfate so epsom salts alone doesn't cut it.