go to your local chemist or drugstore if your american look for kondys crystals just a tiny amount dissolve in water will turn water bright purple...
just dont over do it 1/4 of a gram will make up 20 liters this will keep bottled for around 4 weeks i think its used for tinia or footrot my dad used to soak his feet in it and they went purple lol
Dutch Master
I just switched to Dutch Master Gold. Look on their website, they have a Nutrient Calculator that has really been working well for me. With the 2 part Gold Nuets, no potash gets added, it's already in it.