I have a 28' round above ground pool, 17,000 gal. sand filter. Just had a new liner installed and 3 truckloads of water. Water is clear but algae on bottom (not much). Added 6 gal of liquid chlorine, vacummed, backwashed still there. I am new to the BBB method and new taking care of the pool and am feeling overwhelmed. Bought test kit TF 100. Do I test everything at this point? MY CYA is non existent. I would really appreciate any help. thanks.