Hey Dogfish, I have drained and refilled three times. While the clarity gets better each time, I can only see about 6 inches into the tank. In hind sight I should have rinsed the soil, but now I have to pay the piper. Is this a tannin issue, or a nutrient issue? or both? I will look into hornwort tomorrow. My Wife keeps telling me that it looks like a martian tank, as the water is literally red. LOL.