I got first crack at the local plant club PAR meter, so yesterday I made a simple plastic holder for it so I could easily hold it in position in the tank. It is just an acrylic rod, with a piece of acrylic tube glued to the end, with the rod bent in the oven.
Today I took some readings on my 45 gallon tank:
The tank has a DIY light fixture housing a 2 x 55 watt AH Supply light kit, with GE9325K bulbs.
My data is:
I am surprised and very pleased by the evenness of the lighting over the substrate, and the intensity is about what I was aiming for when I raised the light. This is the tank with the RFUG filter, with CO2 enriched water from the canister filter going into the inlet, so it flows upward under the plants. The plants are all growing slowly, with only one bulb installed. Today I installed the second bulb and will leave it installed.

Today I took some readings on my 45 gallon tank:

The tank has a DIY light fixture housing a 2 x 55 watt AH Supply light kit, with GE9325K bulbs.
My data is:

I am surprised and very pleased by the evenness of the lighting over the substrate, and the intensity is about what I was aiming for when I raised the light. This is the tank with the RFUG filter, with CO2 enriched water from the canister filter going into the inlet, so it flows upward under the plants. The plants are all growing slowly, with only one bulb installed. Today I installed the second bulb and will leave it installed.