Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Soft Pumice stick, definitely not Heavy Duty

Bought 3 of this pumice sticks thought it should do the job (clean my pool whole perimeter's white deposit line once) and have some left over. Oh boy I was completely off the mark. Not only didn't even finish cleaning my pool's calcium deposit line for one complete round, all three were finished by only went through 3/4 round and not all clean still. Worked like a piece hard mash mellow on super hard surface(pool tiles). Not working well at all.