I let my scrubber (DIY SM100 style, but with 6 T5HO lights instead of 4) go for an extra few days between cleanings to see if I could get the "3D" scrubbing working. As the algae grew around the drains, the water level rose as excpected, but so did the tank temp. I normally run 78-79 degrees, but got an alert from my Apex yesterday at 6:00 AM saying my temp was 82 degrees. The algae had restricted flow, and the water level in the scrubber box was around 5-6 inches deep. It seems that the increased time the water spends in the box, and/or the less exposure to the air in thin sheet flow, caused the water to absorb much more heat from the scrubber lights (about 150 watts total). I cleaned the screen and the box last night. The water level returned to the normal 1.5 inches in the box, and the temperature dropped back down to 79 degrees. During this time the room was a constant 74 degrees. The only heat inputs at night are the main pump (Mag 12) and the scrubber lights.
I don't know if anyone else has seen this issue, but it looks like I won't be doing "3D" scrubbing unless I hook up a chiller.