I am a new pool owner and I had everything going just fine until forgot to add tablets before week vacation but got That taken care of with help from Leslie's pools and new chemicals. Now have this new algae that looks like sand or dirt but when I brush it it looks pinkish red. Seems like it all started when I started using this stuff recommended by Leslie's called weekly plus could it be what's causing this. I have cleaned, brushed and shocked and it seems like I remove it all and I go back 10 minutes later and it right back and worse. Any suggestions my pool is 18x30 above ground and I have sand filter pump. Water is clear as can be right now just has this stuff on bottom and when we swim it starts floating around.