DIY lighting for 125g

Yep.

I would like to use the 48" bulbs that I already have, but I think that there is a lot of wasted light in the center if I stagger them. My canopy design is to keep the top hinged glass accessible (outside) the canopy. So it's more of a partial canopy.

I suppose I'll just have to do a mock-up with the bulbs when the canopy is completed.

(Isn't that PVC classy?)

OK, I just realized you posted this is a 6 foot tank. I didn't realize Marineland makes them with one brace though. Lots, like my 125G actually have 2 braces. A real PITA.

Bear in mind that fluorescent tubes begin losing intensity at the tube ends the second you turn them on. Overlapping them in the middle will eventually be unnoticed. There's an added advantage to sticking with 4 foot tubes. They are just easier to find. If you go to 3 foot tubes, that's a length unique to the aquarium hobby, and is just priced like everything else in the hobby.

As a suggestion, you can fill in the space that overlapping the shop lights leaves with two single tube 2-foot T5 fixtures you can buy at Lowe's. About $20 (yeah, nutty when you consider the shop lights cost about $15) a piece. I use them extensively in the fish room with blue actinic bulbs. I leave the house early in the AM and have these set to go on well before I leave so the fish will be awake and active when I feed them, but I don't have to fire up the day lights. I do the reverse when I feed at night. Just a cheap manual timer does the trick and to some extent it simulates a dawn/dusk light cycle. You'll love the tank's colors under the actinics too.

Light is way overrated as a cause for failure in growing plants! It is only one of lots of causes. I recommend going with the four foot lights you have in a canopy which hides them. My best tank is a 6 fooot 125 gallon where I don't try to have the best plants but a mix of my best fish with plants added.
It has a DIY stand and canopy. For lighting, I found a $4 Craftman 48" shop light that has twin T8 bulbs. I added two CFL twisty bulbs over two areas where I wanted to add some light. I feel my plants are fine considering the fish in that tank. Large African cichlids can be rough on plants. Ludweigi, swords, crypts, all seem to do okay. The lights are not the problem!
My tank

My lights

My fish and plants


I find a single four foot light does well enough and I find no problem with the center brace. I now use the two CFLs on a dawn and dusk setting to let the fish know it's time.