Need Kessill Setting Assistance

[BigHildy53]

I'm using an Apogee SQ-520 to measure PAR at various points in my tank. The numbers shown by the PAR meter are very low. So either my lighting intensity is way to low, or I don't understand the numbers, or the meter is malfunctioning. I would like assistance in determining which it is. The specific reading at various points in the tank are in the picture below.

The tank is a 6 foot 180g Marineland tank (72" x 24" x 24"). I have six Kessil A360s 8.5 inches above the water line. The total photo period is 10 hours; with a peak intensity of 40% for 4 hours. Color peak is 35%. I know the intensity is low, but I thought the extra lights would compensate.

I've cleaned the meter with RO/DI water and with alcohol to remove any possible residue. There was no change (other than the to be expected minor variation) in the numbers. The firmware of the device has also been updated.

I have had trouble keeping corals other than some of the most simple. But some are doing well.

 

[Potatohead]

I would believe the meter in this case, 40% is really quite low. I would slowly ramp them up about 5% per week until you're in the par range you want to be.

 

[Crabs McJones]

I would bump up your intensity. while you do have many lights, 40% isn't much power output. On that size tank you can likely bump your intensity up to 70-80%
As @Potatohead said above, do it very slowly and watch your par numbers as you increase it.