Hi, this my first time with this intex 16x48 easy set. I am trying to vacuum it, via the skimmer basket but it is not great suction. The debris bag has a small amount of stuff in it but I think I am mostly just stirring it up as I push the vacuum. I bought a rubber plug to try and block the 2nd intake because I read that that is helpful. When I did that, there was no suction at all via the skimmer basket and nothing going from pump back to pool. Do I need to close off a valve or something? The T valve at the inputs obviously can't be shut off? Could it be due to air still in line? I have a bunch of sand/dirt settling on bottom and it def needs to be vacuumed. Any help/ suggestions would be greatly appreciated. Thank you in advance.