Did some more PAR readings today and ended up turning on the second bank of the LED
lights (blue channel) to 50% power and will see what happens with BBA. One thing I did learn is that ideally PAR readings should be taken before ornaments and plants go in.
This is also all relative as the PAR readings seem to bounce around a bit.
For information the tank depth is 30inches with a quad t5ho and medium-cost LED
strip light (white channel 100% power). The lights sit on the tank rim. PAR readings are:
PAR at 1ft depth (4 weeks ago) - 89.
PAR at 1ft depth (now) - 56.
PAR at 1ft depth (now & no surface ripples from canister filters) - 57.
PAR at 1ft depth (now, filters off and no PERSPEX cover) - 59.
PAR at 1inch depth (filters off and no PERSPEX cover) - from 100 to 150 moving around.
PAR at ~ 1 and a half feet - 17 (off to side).
PAR at 1ft depth (re-test after PERSPEX covers on) - 65 (sigh).
PAR at 1ft depth (added blue channel of LEDs on at 50%) - 76.
So perhaps the readings may be out by 25% but in general was as expected. It was surprising that the PERSPEX covers on/off didn't make more of a difference as these can get quite coated on condensation.
A second flower stem has also popped up so fingers crossed on this one