here is my approximation on the electrical savings..
assuming a 11watt savings..
12 hours a day.. average time span.. 18 months.. with an average 30 days in each month.. $5.70
will need to be replaced every 12 months compared to 18 months.. so that would be a 2 T-5 HO
bulbs for every 3 CF
at current prices that would be a $10 loss at worst..
the penetration for a tank under 20 inches tall IF the CF
has a reflector at all should not be much of an issue if you have enough CF
bulbs.. to the best of my knowledge..
so I am assuming in my case.. with a standard 75 gallon tank if I do a sufficient job cooling the fixture.. CF
might be a better choice.. ???????
or is the penetration more of an issue then I think.. like 18 or 16 inches being the threshold?