I own a 18' x 48" Intex Metal Frame pool. When I purchased the pool it came with thru-wall skimmer and a small pump on the bottom of the skimmer. We need to use a filter cartridges. Now I have purchased a Intex Sand filter 1600GPH Model # 56673EG. But the new filter comes with "easy connections". And my pool does not have them. How to convert the thru-wall skimmer so I will be able to connect the inlet? I can use the existing hole for outlet. Do I need ti cut a hole in the pool wall for the inlet?