Cool, thanks for the tip, I wasn't sure of what you meant originally. Might have to give that a whirl. Haven't built the canopy yet, so the top is wide open, a lot of surface area and evaporation is pretty rapid even without any lighting running yet.

Is there any scientific type explantion as to why the sand particles would settle faster with higher SG? (In english though, I'm no Randy Holmes, so covalent molecular bonding by whatever will go straight to the bit bucket.)