Malawi Death Problem

[Pablos]

I have had a few Malawis die over the past few days, nearly all of my babies!
I went to the lfs and they told me to put some Methylene Blue in the tank to combat disease organisms.
I read the distructions and measured out the correct amount put it in warm warter and stirred it.
Put the smallest of pippettes into the tank and my water has gone blue!
Problem is how long will it stay blue and what do i do with the rest of the mixture?
Any quick help would be great

 

[WILDER]

Never advise putting a med in a tank to you know what you are dealing with.
How many gallons is the tank in gallons or litres.
How many fish in the tank and which type.
Water stats in ammonia,nitrite,nitrate,and ph.
Any symtoms to go on.
Yes the methylene blue will send the tank blue it will fade in time.