@Mr M
Very strange that the Dominator is behaving that way. I'm also using the Dominator, the middle one, not the lite and not the pro/viper models. Also have a 0.75kw pump. My initial experience was less than steller when I bought it late last year. I had also been using the tik tik pool...
I try to avoid vacuum to waste as much as possible. Only when really necessary.
When my pool turns green after a storm I use HTH Green to Blue. It comes with a Sparkle-It Cube and it does make a difference. Takes about 10 - 12 hours to fully dissolve in your weir. I don't connect the pool...