40% WC because I went out and bought some lilaeopsis for the front middle of my tank. Adjusted the CO2, finally getting the drop checker to go green. Roughly 3bubbles per sec @40psi. Enjoying this aquascape thing. Also bought flourish and did first dose. 6ml. I put it into the sump in the refugium. I can't see why that wouldn't work. Figure it would be well mixed before it hit the main tank.