What Byron said hit the nail on the head. Not all tubes are equal and some aren't worth a hoot. Let the moths out of your wallet and spring for decent tubes. Also, I've been scouring high and low for two tube strip lights. Did they stop making them ? I like to use multiple tubes to be sure I'm getting a complete spectrum. Different tubes, not the same.
I don't know if no one is making them (the dual T8 tube fixtures) but I was not able to find any online or locally except for a couple of old ones still unsold. My ballasts from the 1990's began giving out a few years back, and after trying LED I decided it was best for me to buy a dual-tube T8 shop light and fit this into the housing of the older fixture. Worked well, and I am no mechanic believe me. I got the shop fixtures at Home Depot.
Now, forward to the present--guess what, they are phasing out the T8 shop fixtures now.
I have so far stayed with T8 because I understand it and for my low to moderate light requiring natural planted tanks it is just about as good as it can get. I'm sure there is good LED somewhere, but it is very expensive, but in time may be the only solution. T5 is no good for such tanks as the light is far too bright; I tried one and took it back after a week on the tank, fearing my fish would be asking me for sunscreen and sun glasses if I left it. Nice for corals, but not freshwater low-tech.
I too like the dual-tube, and I had this on my three largest tanks (70g, 90g, 115g) using one Philips Daylight Deluxe 6500K and one Philips Daylight 5000K. Excellent light, high in the red, blue and green. Downsized at my move in May, but using 24-inch tubes I fitted shop fixtures in the housing over my 33g and 40g tanks so they both have dual T8 and I use one Life-Glo 6500K and one ZooMed Tropic Sun 5500K. I have an inkling the ZooMed is being phased out in T8, so when these are no longer available I will go with two Life-Glo 6500K.
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