Hi,
Limiting phosphate will definitely slow down the cyano. The cheapest and easiest method to get rid of Phosphate is with Foz Down. Here is a link to the product website.
http://www.oceanfreshaquarium.com/foz-down/
I use the Foz Down in my SPS culture system to control phosphate and I use VSV dosing for the nitrates.
Cheers,
Tim