The methane-blue green algae connection, page-9

And burning methanol produces CO2 and H2O. Still, to take CO2 out of the atmosphere to make methanol to burn it again is at least carbon neutral, provided the energy used to make the methanol is carbon free renewable energy. Still think a better and simpler way to store excess renewable energy is to make hydrogen from H20. When it burns it only releases H20 into the air.
Not sure what any of this has to do with Phoslock though, apart from a similarly named energy company.