Hi,
i've found photoperiod puzzling so far in my 2 years of MTS.
My very low light 20G seems to not care if it is 8 or 11 hours light. Just grows slow with a little algae whatever. No dosing.
My big 46G corner tank gets fuzz algae and green spot on leaves when i try and up it to 9.5 - 10.5 hours. Seems to be happiest at 8.5 algae wise. Its about 2 wpg with EI dosing with plenty of phosphate in the water.
My 5.5G has about medium high light with mostly mosses and about 10 hours of light a day. It's got algae issues on bits exposed to the light too much, but ive not done any proper dosing for it yet.
ID hazard a guess that the answer would be totally dependant on the setup of the rest of the tank; parameters, plant mass, dosing method, light strength and type. With the perfect balance of those and the lighting duration to produce an algae free growing environment.
I've not seen much in the ways of hard and fast rules on light timing in my reading on aquatic plant growing. Other then the discussions about having a break in your light period to discourage algae and a vague memory of a chart somewhere that had a list of recommendations against tank size.
Is there one for tank size & lighting strength in approx wpg?
Best Regards,
John