hi im Dave and this is my second season with a pool. i bought my home with a pool and learned everything i know from youtube and Leslies nearby. i been reading about chemicals and im confused.i use trichlor in my skimmer and powder shock sometimes. last year i only used trichlor and eventually algea started to grow. people wouldnt notice but i did. it wasnt bad just a few spots where water didnt circulate like corners. this year i use more shock (powder) and phosphate remover. i get my water tested by leslies every month and adjust accordingly. am i doing this right or should i be doing something different. of my tests i never had an acid problem, ph or anything else out of balance, so far my issues were low chlorine and high phosphates and low alkaline. i added the necessary chemicals to balance the water. im afraid when i have a real problem how do i prevent this.