We didn't have to put the patio blocks under the pool, we just chose to do it that way we were sure it was level. As long as it's level it's fine. And the pump has a long cord on it that gets plugged into an outdoor GFCI outlet.
I've seen the new oval intex pools (and our metal frame actually was bought from QualityInflatables) To me it seems smaller than my 18'. Sure it's 2' longer, but it's also alot narrower. It says it uses 4300 gallons, and the 18' says it uses 5600 gallons. And if I'm not mistaken, the width on the donut ring pools is measured at the widest point on the pool (usually about half way down the wall) so the donut is actually smaller than the stated size. The metal frame walls don't bulge out so the top appears larger even than the same sized donut kind. Whatever you decide, your kids (and you) will have a blast in it! Let us know what you decide.
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