Hi, Would concur with PO. I'm doing much the same. I'm rolling the loose straw in nylon mesh netting and anchoring much the same way. Straw won't kill existing algae, but will remove condtions favarable to algae growth. I paid 4.00 per 25-30 lb. bale. Water temp. needs to get up around 50 degrees before natural chemical reaction starts. Slydog
