I wanted to start a discussion regarding tanks that have a lot of
light, at least 3-4 watts per gallon (wgp).
I hope you are injecting CO2 with that lighting level. When you go over 3 wpg,
CO2 is mandatory, not optional.
With a 46 gallon tank, it can be hard to get enough CO2 in the water with DIY.
I would go with compressed CO2. You could run all your tanks off of a single
CO2 cylinder.
Leigh
http://www.fortunecity.com/lavender/halloween/881/