I got my light bulbs for my light. They were the only T-8 lights the store had for this light.

Here is my respectfully submitted opinion on plant lights, having used them for years. I started off with the old-style dual 4' fluorescent fixtures, obtained from places that were ripping out same and installing newer "eco" fixtures. Scrap Dealers, Electricians, etc. About $10. each. They worked great until I noticed dripping from the ballast, presumably PSB's. Then I started to purchase newer T8 fixtures. Their "34W claim equivalent to 40 Watt" simply does not live up to muster. One could easily see that they were much dimmer, and they burn out very quickly. Then I noticed on Amazon, that one could buy LED 4' bulbs to insert in the T8 fixtures, no wiring, just remove the T8 bulbs and insert the LED's. Far more brighter light, as I recall, something like 5000 lumens and a guaranteed longevity that will probably outlive me. LOL. All my plant light fixtures are on $10. timers available anywhere, so I can set the time to come on and go off. Cheers.

I should have mentioned, that I incorporated raising/lowering cords on each so I can set the level wherever I want, within reason. i.e Shelf height between shelves.

Thanks for the information, Frank!

@fwmosher
Frank:
       Your comments on the lifetime and light output of T8 vs T12 bulbs do not jibe with manufacturer's ratings and my measurements. Cited below are some typical results from a much larger survey I made two years ago, and I have no reason to suppose it has changed appreciably. The 32-W T8 lamps have a 150% longer life, 133% the lumen output and 75% the power consumption of the 40W-T12's. My own measurements with a lightmeter and wattmeter approximately confirmed those output and power ratings, but I haven't had them long enough to check their expected 8-years life in my grow-rack.
      Last year I started experimenting with 4ft LED shoplights that have about the same lumen output as T8's. They are more expensive to purchase but may have longer lifetimes. I have not yet tried the replacement bulbs you describe. I've added data for the Utilitech and Luminance T8 LED models below. They have an impressive lifetime and a smaller power requirement, but both have even less light output than an old T12 bulb, and come at a higher cost per bulb.

   Syl T12 40 Watt   2180 lumens 20000 hours   6500°K    $28/10=$2.80 ea
   Syl T12 34 Watt   1925 lumens   20000 hours   4100°K   $40/30=$1.33 ea
   Syl T12 40 Watt   2150 lumens   20000 hours   4100°K $22/10=$2.20 ea

   Syl T8 32 Watt   2850 lumens   30000 hours   6500°K   $36/12=$3.00 ea
   Syl T8 32 Watt   2900 lumens   30000 hours   4100°K   $28/12=$2.30 ea
   GE T8 32 Watt   2900 lumens   36000 hours   4100°K   $54/30=$1.80 ea

Luminance T8LED 12Watt   1200 lumens   50000 hours   5000°K   $23.40 ea
Utilitech T8LED 18Watt      2000 lumens   50000 hours   4000°K     $7.50/2=$3.75 ea