a reactor would be best for a tank that size...otherwise multiple glass diffusers would be needed IMO
what sort of filtration does the tank have?
Please see these reactors if interested
http://www.azaquaticplants.com/community/showthread.php?t=10975
what sort of filtration does the tank have?
Please see these reactors if interested
http://www.azaquaticplants.com/community/showthread.php?t=10975