With the light lowered 4inches or 10cm to sit on the glass tank top, I'm picking up about an extra 20% PAR. I assume it was just getting reflected off before. Which was why the family were saying the light was bright whereas I knew the LED
lights were brighter.
I count just about any bubble as pearling but I could see this extending across about two thirds of the tank tonight (from CO2
reactor). So even though a small drop in light height, it seems to have a big difference.
However I found I had to shift the light right over the light meter otherwise it actually read lower! So I'm not getting the spread of light that I was. Hmmm, no such thing as a free lunch unfortunately.