Ok Myka, maybe this will help. So here are a couple more readings of 2 x 48" 54w T5's on their own and with my 3 x XR15PRO Radion's.
I expect the T5 readings to be a little better once I have them spilt, front and back but they are pretty close with them both mounted at the back of the tank because the reflectors do most of the work. Anyway, you get a general idea of whats what. You literally just add the PAR of the T5's to the PAR of the Radion's, the increase is pretty straightforward.
With that in mind, I would expect 4 x T5's with the same bulb combo to produce 300 PAR mid-tank and 150-160 PAR on the sand bed. But where the Radion's give you wide variations in PAR numbers throughout the tank based on the lenses used, the T5's provide consistent PAR throughout the whole tank, front to back (only minor changes in PAR).
Adding 2 x retrofit T5's to a couple of Radion fixture's is a cheap way to boost PAR numbers and maximize coverage. Possibly adding improvements to growth and colouration to any SPS that were in lower PAR areas. A T5/LED combo fixture seems to be the fool-proof way to go if you're chasing PAR readings.
I personally love my Radion's and have not yet seen any need to turn the T5's on. Everything seems healthy, growing and colourful and I really like the shimmer in the tank. Though I will run the T5's later in the year for a few months to see if I can actually see a noticeable difference in growth or colouration, just for funzies.
T5's ONLY
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T5's & Radions
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Radions ONLY
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