If it were as simple as adding the PAR from the two fixtures, then that would be great. However, since you need to factor in distance, distance from center, and the fact that the light is coming from two different sources, it's not that simple. But the combined total PAR values will give you a ballpark value.
I looked up the PAR values for the Finnex RAY2 and could not find it for a 30" fixture but I did find it for a 24" and 36" model. At 18", the 24" model produces about 39 PAR and the 36" produces a little over 60. Quite different indeed. An average would be around 50 PAR.
One source I found had a 30" Finnex 24/7 producing around 48 PAR at 18".
If you could combine the values, it would be close to 100 PAR, well into the high light classification (with the ranges at 10-30 for low, 30-80 for medium, and 80+ for high).
If I were you, I would run these on:
1. Separate timers, with the 24/7 in manual mode
-OR-
2. A timer for the RAY2 and the 24/7 in 24/7 mode
In the first scenario, you could adjust the amount of overlap time with each fixture running "solo" on either side of the combined times. I think this would give you pretty good control with the lighting
In the second scenario, you could set the timer for the RAY2 so that it is on during the peak time of the 24/7 in 24/7 mode (roughly 11-3 pm). The amount of time (and when) the RAY2 is on will be your throttle for light output, so to speak. I like the colors produced by the 24/7 during non-peak hours. Fish seem more active during these times.
I'm not going to get into CO2 since that was not part of your question. I will emphasize that whatever you can do to have control on the amount of light is one key to a successful planted tank.
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