It's all about phosphate in your case. A reading of .2 ppm with a hobbyist grade test kit is WAY high. Phosphate should be below .03 ppm which for all practical purposes means they would be undetectable with a hobbyist grade test kit.

First you need to figure out where all of the phosphate is coming from. Are you adding it to the tank via food (overfeeding) or make up water (tapwater), etc.? Is it coming from your liverock (often the case with newly setup tanks)? Do you have some other type of nutrient sink such as a non functional sandbed, gunk built up in your filters,back corners of your tank, etc.?

You might consider picking up a good phosphate kit (I like seachem's), using an iron based phosphate remover like phosban either in a reactor or just in a canister filter, and doing a thorough cleaning on the tank. By cleaning I don't mean water change but rather siphoning off detritus from the holes in the liverock, back corners of the tank, sump/filters, etc.

I don't know about Red Sea salt but personally I would stick with IO. Lighting really doesn't have much impact on cyanobacteria, it's all about nutrients and flow.