Water too clean?
I use RO/DI water for my CPs. This generally has <2 TDS and I aslo use the water for topping off my reef aquarium.
Is the water too clean for my plants? They don't seem to be growing a lot. I'm thinking of mixing in tap water to get it a little dirtier.
Let the water stay pure, add in some Urea Free Orchid Fertilizer periodically if you want to add something back.
I like Grow More brand (I've used it for 10-12 years now): http://www.amazon.com/Grow-More-5271...ow+more+orchid
I would be extremely careful using fertilizers on most carnivorous plants. Nepenthes and Sarracenia will definitely benefit from some ferts once in a while but, they can be certain death for Drosera and others if overdone even a little bit. Leave the water pure and consider other possible issues with your conditions.