I have a pasta sauce jar that a few leaves at a time soak in along with indirect sunlight. This acomplishes two things. first the tanic acid is leached out (I don't like the blackwater look either) and it creates a perfect place for the infusoria culture to mature = plenty of food for your wee ones
I replace 80% of the water a week with dechlorinated or RO water. Hope this answers your questions.