I'm glad to hear it's looks like it might do the trick for you. Don't you
love it when you pull off a good diy?

Ron

"Jim Seidman" wrote in message
om...
I took the plunge and decided to try an overdriven hood. I have
35-gallon tall hex, and the All-Glass light fixture contains a single
puny F15T8. Given the depth of the tank, this is hardly sufficient for
plants.

By gutting the original fixture, I was able to fit in two F15T8s. This
is largely because the original design needed a fair amount of room
for the internally-mounted ballast. I switched to an external ballast,
which was necessary anyway because of the larger size of electronic
ballasts.

I mistakenly thought that I could overdrive the F15T8s by just hooking
them to a ballast designed for two F32T8s. Wrong! At least with the GE
ballast available at Home Depot, the ballast somehow compensates for
the tube type. This ballast is actually rated to run anything from
F32T8s down to F17T8s, all at a ballast factor less than 1, and when
hooked to F15T8s provided only normal light output.

So I returned the 2xF32T8 ballast in favor of a 4xF32T8 ballast, and
tied a pair of outputs to each bulb. Wow! This really produces a
noticeably brighter light. I wish I had some way to quantify the
difference, but I don't have any of the appropriate tools to do so.

I ran it for several hours yesterday with no signs of overheating. In
fact, the fixture doesn't seem noticeably warmer than it was back when
it contained the internal magnetic ballast.

I pretty excited now to see how well plants will actually do with this
setup. I'm planning on using a combination of tall plants (like
Limnophila sessiliflora) that can get closer to the lights, and
shade-tolerant foreground plants like Anubias. I can't set up the
aquarium until next month due to the hallway being painted, but I'll
keep you all posted.

- Jim