algi on soil

hi has anyone got a cure for the green algi growing on my soil in my g/house and polytunnel tryed turning it over and it just grows back like a green carpet all over my soil . is there anything i could use to prevent it .hope someone can help p,j,.

i have never tested my soil  so it could be that it is acidic. will buy a test kit and test my soil . the g/house and polytunnel has never been limed but my outdoor beds  have so thats proberley why i dont get it outside . would the algi cause any problems to my crops and what should i do to prevent it thanks p,j,.