What have you done to lessen the nutrients in the water column that are feeding the cyano
? Chemiclean is only a bandaid and without removing what feeds it and increasing flow will it go away.
I would not treat again with the chemiclean and do a large water change to cut your nitrates/phosphates down. The size would be determined by how high the nitrates are...if they are 40, do a 50% water change to remove 20, as an example. Follow that up with cutting back on feeding and see how things go from there.