I have a 150 gallon reef tank with sump which has been set up for 6 years. I noticed a small amount of turf algae 12 months ago which I should have got rid of but now it’s multiplied & is encroaching on my corals. I’ve recently tried Brightwells Razor which did absolutely nothing. I thought I’d try Flux RX but not sure how long I should wait after water change before using. Has anyone ideas or could give me advice. Hope you can see the dark patches on picture. Thanks Sandra