Good news Grover65K!
Normally the water would be getting greener and darker with the longer day lengths and stronger intensity sun so it's most definitely improving.
Wait to see if this improvement continues but I was also thinking you could boost the effectiveness of your UV by putting them in parallel with a much higher water flow.
The trick is to put the water through the UV system faster than the green water can reproduce in the pool so 30,000 LPH - 40,000 LPH during the day (solar panels).
Would be easy to plumb up your existing 4 UV filters similar to this link below.
So high collective flow rate but individually low enough flow for effective kill cycle.
I will be building a 600 - 800 watt UV system similar for myself in the next few months to kill white spot (without chemicals).
I priced single unit UV systems and couldn't find one below AUD$10K so I will join 10 smaller (75 watt) units myself.