I haven't kept a planted tank in a while and was wondering if anyone here does?

1) has anyone tried the carbon block CO2 injectors (rather than having a CO2 bottle it uses electrolisis to release carbon atoms into the water?)

2) I am thinking about putting halide lights on the tank... this would be a step up for me in terms of planted tanks, I have only done standard output flourescents... but I love the way halides look on planted tanks.

I know that for flourescents the rule of thumb is 2.2 watts per gallon, wondering how that changes with halides.

on a 110 tall I was thinking of doing 2 x 250 watt 6.5K bulbs.