Treating with Potassium Permanganate (PP).KMnO4,When you have found Trichodina on a scrape.
First off you must know the EXACT gallonage of your pond including the filters(total water content of your entire pond system) Overdosing with PP can be fatal to your Koi and under dosing is useless.
PP is an extremely aggressive treatment use with great care.
You will need a accurate set of scales to measure out the PP as it is measured out in grams.
A jug made of glass or food grade plastic to mix it in,the jug will need to hold around one litre,and a suitable spoon or dowel to mix it with.
Also a clean watering can and some gloves (it stains what ever it touches)
Measure out the pp exactly and add it to the jug and pour in some boiling water about 3/4 of a litre
Mix until all of the PP is dissolved and let it stand for fifteen minuets. While you are waiting double check your calculations on how much PP you need if in any doubt start again)
Half fill a watering can with pond water, stir the PP in the jug again and add to the watering can, then pour the PP into the returns and air columns in the pond over a period of Twenty minuets.
The pond will turn purple – you need to maintain this for NO MORE than four hours (two to three hours is normally enough to kill Trichodina).Once the PP has turned brown it is spent.To check this look at the air bubbles in the water as it is easier to see the colour there.
If the pond turns brown in less than two hours you can add more PP in very small amounts to maintain the purple colour.(The more the organic load in the pond the faster the PP will turn brown) I would not advise using PP in a natural or planted pond with a heavy organic load as you will need to use very high amounts of PP and this will not be good for the Koi.
NEVER dose the pond at night or if you will not be able to check on the Koi regularly,If at any time the Koi become distressed by the treatment you can neutralize it with Hydrogen peroxide.
To neutralize the PP at the four hour mark or in the case of a bad reaction the dose rate for the Hydrogen Peroxide is 10 mls of Hydrogen Peroxide 3% to every 150 UK gallons.(It is worth pointing out that if you use the HP it will remain in your pond for approximately four days rendering any further treatments ether weakened or useless.
Always follow the dose rate given by the manufacturer.
Simple rules when using PP
Add as much extra air as you can
Know your exact gallonage
Check and double check the amount of PP you need and use accurate scales
Never dose if you will be unable to observe the Koi regularly for the time of the treatment
Always have some HP ready in case of problems.
DO NOT MAINTAIN PURPLE WATER FOR ANY LONGER THAN FOUR HOURS
DO NOT USE PP WITH STURGEON
Check oxygen levels before using PP especially in stormy weather.
This is the protocol and dose rates I use on my ponds what you do is up to you