There's different kinds of fluorescent tubes?

T-12 tubes - common shop lights- requires T-12 fixtures...the weakest light
T-8 tubes - a stronger improved shop light- smaller in diameter, but stronger light - requires T-8 light fixtures
T-5 tubes and T-5 High Output tubes. The strongest of the fluorescent tubes & the most expensive. The T-5 HO cost about as much as HID lights.....they require their own special fixtures.

A 250 watt HID light is perfect for 2-3 flowering plants...IMO.

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