Jestersix

KMnO4 and how to measure it

S

sfsuphysics

Supporting Member
BARcard
Rather than buying a 2 pound jug of the stuff, which isn't that expensive, I decided to talk to the local chem lab stock guy here at school, and bingo bango no problem got some! Now the reason I didn't want to go with buying it is because according to the Borneman article a dosage of 50mg per liter is sufficient, now do the math on that to see how many liters 2 pounds will treat! So I got 2.2 grams from the guy instead.

Now here's the kicker though, how the hell do I measure out 50mg? There is no kitchen scale out there accurate enough for that, and I'm not going to fork over bucks on a precision digital scale. I can measure it here in the lab, but I'd rather do this in the comfort of my own home. So I was thinking maybe just split the 2.2 grams into 44 equal piles (a chore in itself!) or something.

For the nuking of algae I REALLY want to experiment with, then overdosing probably won't be an issue.
However for utter destruction of nudibranchs... apparently you can overdose with 4x the desired amount.

So should I just mass it out in the lab and make little packets to take it home? Or is there a simple method I'm just not thinking of?
 
For us normal folk it's Potassium permanganate

How does it nuke algae?

I would measure it in the lab if you have access to all the fancy equipment Mike.
 
Yeah I know what it is, just couldn't remember how to spell it, and writing out the molecule was easier :D

I don't know the how to.. I'm not a chemist, just one thing in that reefkeeping article that Borneman wrote really stuck out to me
It reacts with any organic matter including algae, bacteria, fish, particulate and dissolved organics, and organic bottom sediments (note: it is quite effective at killing algae on rocks (Todd, pers. comm.)).
Click to expand...

I did end up measuring it with the lab equipment.
 
I wonder if it's anything like OxiClean?

I know Jeremy mentioned it before during one of the meeting. I believe he says he uses to clean up equipment.

I use to clean up nasty algae when I break tanks down.
 
Check out the table on page 7 on this pdf.

http://aquanic.org/publicat/usda_rac/efs/srac/410fs.pdf

8 grams/teaspoon, which is close enough. I cross referenced against some bulk density numbers etc.

Best thing to do is to make a concentrated solution, then add the appropriate amount of that to your 1 liter or whatever of tank water to get the desired ppm. That way you don't have to struggle with trying to weigh milligram amounts of the KMnO4.
 
Ok, and the math...

2g/200ml= ~10ppt stock solution

1ml of stock solution per liter of tank water gives you ~10ppm

If you use 1 ml / cup of tank water for dip, you get ~40ppm which is about what you want to experiment with for dipping.
 
Alright, I don't have a chemistry background so maybe I'm just confusing things

Borneman states 50mg per liter.. so at 2g per 200ml give you a concentration of about 200:1 of what is recommended.. so 1ml per liter of water gives you about the 50mg per liter concentration.

Now I'm not getting the 1ml per cup bit that you tossed in, why would you want 200mg per liter?

And I thought about making a concentrated solution, however I'd be a tad worried about shelf-life. Would it somehow lose it's potency if not in a completely air tight container? These are chemistry issues I don't know how to answer :)

Eitherway we have this scale with a 0.01 gram accuracy so I'll only be 20% off at best as I measured out my 50mg packets :D
 
Density of water is 1g/ml or 1000g/liter


50mg/l = .050g/1000g = .00005g/1g

.00005 X 1,000,000 = 50 ppm (parts per million)



2g/200ml = 2g/200g = .01g/1g

.01 x 1,000 = 10 ppt (parts per thousand)

That's the concentrated solution.

Put a ml of that into a liter, the concentration is 10ppt/1000 = 10ppm.
 
Alright Norman, sounds like my math is correct just said it in a different (non chemist) way :D

Began tests on algae destruction. First a 50mg/l sample then a much more-mg/l sample (the overboard method to see if that has any effect at all).
 
[quote author=Mr. Ugly link=topic=2445.msg25061#msg25061 date=1190845709]That's the concentrated solution.

Put a ml of that into a liter, the concentration is 10ppt/1000 = 10ppm.
[/quote]

And the 250ml (~1 cup) comes in because 1ml of concentrated stock solution per 1000ml of tank water gives 10ppm. So 1ml per 250ml of tank water gives 40ppm. If you want to hit closer to 50ppm, then use 1ml of stock solution to 200ml of tank water.

Oh, and I don't expect the stock solution to deteriorate over time unless it gets contaminated with something that can get oxidized.

And some fun chemistry warnings....

Don't ever pour glycerin over KMnO4 crystals.

Don't create a greenish yellow oily manganese septoxide liquid by adding concentrated sulfuric acid to KMnO4.

Especially don't dip combustible materials such as paper or wood chips into the oily liquid.

:D
 
Man thanks for all the helpful ... "Tips" :D Wasn't too long ago that I found out how easy it is to make thermite as well! :D


Anywho, my testing is going...

After 2 hours in the 50mg/l concentration I've come to the conclusion it doesn't do squat to algae except maybe turn it purple. Now it might be dead at this point, but I can not tell I could put it into a cup and wait over night, but other things could affect this.

After 1.5 hours in the uber concentration (so purple it's almost black) all the algae has turned a deep purple color, however it is still attached to the rock.. again might be dead or on it's way out, but we'll see I was really hoping something somewhat spectacular like the stuff simply melting but no.. However it does seem quite a bit more limp, so who knows.. maybe a day in a QT tank to see what becomes of it is in order.
 
Contact your local drug dealer..... I mean Pharmacist, to weigh it out. Make sure he doesn't short you.

I use Oxi-Clean to clean plastic plants dead coral skeletons (doctors office type tanks), I've used it on live rock as well to give it a good scrub.

Permanganate I've only really used for as a treatment for Argulus


OT Oxi-Clean Guy or the "Stop the Madness" lady who was more annoying?
 
I have a digital scale that measure from 0.1g to 250g, that I picked up on eBay for measuring dry ferts for freshwater. It's not exactly 50 mg, but it's close enough and you can dilute the solution down by half by just doubling the water used for the mix (2L bottles are easy to find).

Picked it up for something like $20 on eBay awhile back.
 
You must log in or register to reply here.
Back
Top