Here's my 2 cents:
For the algae on the glass use a BIG UV sterilizer. When you wipe it off the glass a lot of it is in suspension and will resettle in hours. Use paper towels to wipe the algae off, just use once then throw it away to reduce algae going back in suspension.
Experiement with dosing ammonia to feed the aiptasia to increase thier growth rate. (Check the research, anemonies need the ammonia from fish.) I would not reduce lighting and might even increase it, reasoning is if the aiptasia increase their growth they'll compete better against the algae.
Cut back on water changes. 10% weekly should be more than adequite. You'll see changes in the nutrients and ecosystem initially but you're basicly shifting your system to use your aiptasia for filtering.
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