Hoppy is dead on with that about BBA. Crank up the CO2 and maybe try an every 3-5 days water change for about 2 weeks. ALSO-- 2 times the suggested dose of SeaChem EXCEL for a week or so (and hitting it really hard after water changes) has worked very well for expediting the departure of BBA-type algae.
Lighting-wise, I have alwayd done the 9-10 hours continuous without issue.
Ok tks Hoppy. I'll try to increase it slowly. I'm just getting ove a bout off BBA. Something in my tank is out of whack and I'm still trying to figure out what it is.
A 55 AHS on a 15G is a lot of light. So you might be better off in the ~ 8 hour area. I have an AHS 55 watt on a 26 bow and use to have some AHS 36watts on a 15 gallon and a 10 gallon and those were plenty.
I tend to run an ~ 9 hour photoperiod from 1pm to 10pm on my two main tanks. Works pretty well for me so I can see the fish when I get home after 7PM. But I manually turn them on for about 45 minutes in the morning for a fish feed - before I go to work.
Three Tanks...Eheim 2128 & XP3-90G, Eheim 2128-65G, Eheim 2232-25G.... Tek 4x54 watt T5-90G, Aqualight 96watt PC 65G low tech, 65 watt Aqualight-25G.... Hydors-90G & 65G ... Flourite in 90, 65, & 25 Gallons, .... Auto Water Change/Auto dosing on 90 & 65 gallon..... AGA member......