u/DiveTender

I recently set up a Funsicle pool. Its the 14 foot recalled special 😆 my wife found it at Walmart for $50. After finding this sub I have learned the Sand Filter is most likely going to be a purchase for next season, but can anyone explain to me how this vacuum works?? I have the one that comes from Funsicle plugs into the filter skimmer thing. I have the adapter and there is only 1 way to hook up but there does not seem to be ANY suction. I am trying to get algae cleaned up. The pump starts off great and then after about 5 minutes the water pressure drops significantly. Are these stock pumps just that bad??