a 4 week old tank is new and your still going through growing pains. All your numbers are good. Doing a regular water change is good but doing many IMO
makes no sense. Can you post a pic.. You may just have diatom algae issues which will burn out over time. No need for a UV
at this time.. Take things slow and read up and keep up on the testing and water changes ever 2-4 weeks is fine..
Cutting back on lights is good.. Waht type of water do you use and have you tested the top off water and new salt water for PO4
and nitrates.. If you have any of these in the new water doing a water change is just feeding the problem..
I have to clean my glass all the time also, not a big deal. When I had a UV
it cut back on the cleanings some.
I would wait before dumping money into a UV
till the tank gets older.. A UV
will not help the HA, it may help on the algae on the glass.
test tap or ro
water.. how about a pic..