Potassium Permanganate

[chin_lee]

I have the crystalized Potassium Permanganate and I was wondering how much to dilute this stuff to be used as an oxidizer to get rid of cyano? There are several products in the market that sell this stuff in diluted form already but I don't know what percent they are diluted at? Some products instruct 2 doses daily and some are 3 so I am not too certain. Does anybody know and if so, please give easy instructions as well (eg. 1 tsp crystal to 1 liter water to make X% solution.)
Thanks

[Randy Holmes-Farley]

Chin:

I know Albert Thiel at one time recommended adding permanganate to tanks to raise ORP, but I personally would not do so.

Presumably, you are hoping that it will oxidize dissolved organics and remove them as a nutrient source for cyano? Wouldn't it be just as likely to oxidize living tissue?

It will also likely convert the iodide in the tank to I2 and/or iodate. The bromide in the tank to Br2 and/or bromate. I would not want to increases these processes in my tank.

I'm not going to recommend a dose (except 0% three times a day), but here is an article where Albert does:


http://www.reefs.org/library/talklog/a_thiel_080998.html

[Gamera]

My experiences with potassium permangante in the lab lead me to recommend not using this thing at home - in any way shape or form.

There simply is no good way of using it in a home setting, dilute or not, with the necessary safety precautions at hand.

The stuff is nasty, produces a large amount of heat during the reaction and is indiscriminant in what organic compound it reacts with. That's not to say, naturally, that you should never use the stuff. At times, it's the only thing I have available to do a particular job. I don't mind working with it, but I would certainly look for a different alternative. Even under high dilution I would look for something much less harsh as an oxidizing agent.

Whether or not I would use it as a means of controlling dissolved organics in a tank is something I base off my experience. And as you can clearly see, it's a resounding no. To be honest, I can't even imagine why someone would even think of using an oxidizer as strong as permanganate as a means of controlling dissolved nutrients by adding it directly to a tank, diluted or not. Additionally, as Randy mentioned before, permanganate will not only oxidize free halides in your tank, it will do so until you achieve an inert oxidation number (I believe it goes from Mn(IV) to Mn(II)).

In my opinion, if you really want to control dissolved organics, keep tabs on what you put into the tank and what you're doing to take stuff out. Add water changes when necessary. If you think it's less work to introduce additives, you may be in for a surprise.

But, again, this is just my two cents. Take it with a large grain of salt.