[Rex Grigg]

What size tank? 2 wpg on a 10 gallon tank is not enough. 2 wpg on a 125 gallon tank is plenty.

 

[Rex Grigg]

2 wpg on a 20H is a little on the low side IMHO. Unless you have really good reflectors.

 

[Rex Grigg]

Don't go with the screw in bulbs. You lose way too much light to re-strike.