I bought a bottle of Elector PSP off of Amazon to take care of some stubborn lice on a few of my hens, but the dilution rate is so low that I will never use the stuff up before it goes bad. I don't want it to go to waste so if anyone wants some for their flock, I'll happily mix a few liters for you for $5. The bottle I bought was $235 so this is a great deal for anyone looking for this stuff. The ratio is 1 tsp of Elector PSP to 2 liters of water so even if you have a large flock, that should last you a long time.