The ones you have look like the ones sold by the Mart people for Reptile's cages.
If so aren't they pained white on the inside ? If that is true, I'd think they are better than that which you are checking about replacing them/w.
That's like Petsmart/Petco etc. that I was talking about. What size tank? From top
If you are using the 13W CFL bulbs, they may be a bit less than you could use. But the 26W ones may cause the tank algae if you don't raise them just a bit.
Three 13W bulbs are less light than two of the 26W ones and I mentioned this because I've seen three and even four of those on a 55g tank due to the depth.
What is your reason and objective in asking this BTW?
It's a 20 high so with lets say 2 inches of substrate 14 inches, yes they are Walmart lamps painted white inside with 13w 6500k.. I'm asking because I want my dwarf sag to grow a bit shorter..Adding co2 again so figure the light increase shouldn't hurt.
I believe it is better to have that type of reflector suspended at least a couple of inches above the top of the tank, so enough air can flow through the reflector to keep the bulbs cool. Most of the CFL bulbs we can easily buy don't last long at all if put in closed up reflectors, due to the heat. The higher the bulb wattage, the more heat they give off, so you might have trouble with more than 13 watt bulbs in them, if they sit on the glass as those seem to.