Green water--- UV needed ???????

Hi

Whenever I do a water change, the water that I remove always has a hint of
green.

I've been using carbon/phosphate removers on and off, but this doesn't seem
to get rid of the green.

My rocks turn green as layers of green particles seem to settle on them.

I notice that UV sterilisers are used in ponds to remove 'green water'

would this do the trick here ?

Tank
600 litres
2 x 150 MH lighting (8 hours/day)
2 x Blue Actinic (12 hours)
Deltec Calc reactor
Deltec apf600 Protein skimmer

Ammonia 0
Nitrite 0
Nitrate trace
Calcium 480
PH 8.3

water change 50 litres/wk