I had the pleasure of attending MACNA in San Diego this past September and entered my water sample to Aquaforest for a free ICP water testing. The water sample was collected on October 7th and the results were received on October 31st. I really like how Aquaforest tests a sample of your RO water and your tank water to see what elements are being added through your RO water before you mix the salt and other additives or food in your tank.
I replaced both of the Hamilton 20K metal halide bulbs but kept the same T5's running. The bottom of the metal halide pendant is 9.75" above the water surface and PAR increased on average 23% versus the 9 month old metal halide bulbs. The left metal halide ballast is drawing 269 watts and the right side is drawing 257 watts.
I borrowed an unopened Apogee MQ-500 quantum meter to test the PAR readings on both of my tanks. The metal halide bulbs on the 120 gallon are 9 months old and the T5's are and the bottom of the metal halide pendant is 9.75" above the water surface. The bulbs on the 80 gallon are 11 months old and the bottom of the Sunpower is 8.5" above the water surface.
Bulb combo: 2 Hamilton 20K & 2 ATI Actinic
Bulb combo: 4 ATI Blue Plus, 2 ATI Coral Plus & 2 ATI Actinic