I had a feeling I'd answered this? Maybe not.

The Chroma 50 should work fine assuming you match up the power and tube size. Not sure what you want from a "daylight" tube, there are many tubes which carry that description and some of them will cost less than $6. For the Chroma 50s that's a good price, though, I doubt you'll find less unless you want to buy a whole case.

"Daylight" colour temperature, 6500K or so, tubes are readily available for a dollar or two, then there are endless variations of CRI and spectrum at various prices up to even more than the plant & aquarium type tubes.

Thanks for your response. Actually "daylight" might have been the wrong word. I probably should have said "full spectrum." The article at the following link said that Chroma 50 was one of three types of bulbs--Colortone 50 and Designer 5000K were the others--with "an output spectrum that is similar to sunlight." Since Chroma seemed to be the least expensive, that's the one I thought I should go with. But, if there is something less expensive that would work as well, I'd be happy to hear about it.

I generally use the cheap Lights of America fixtures from Walmart. Since the Chroma 50 is 40 watts and 48 inches, I'm assuming it will fit in those.

Here is a link that might be useful: Indoor Plant Lighting

Measuring "full spectrum-ness" by CRI, you are unlikely to find anything better than the Chroma 50 for less money.

In Europe, but not in America the last time I was there, Lumilux Deluxe fluorescents are similar and generally cheaper. If you want to do some searching, the relevant tubes are referred to as 965 (which means full spectrum 6500K colour) or sometimes 950 (same thing, but 5000K colour). You could also search on the tube spec such as F32T8 for a 32W T8.