Looking for AG Advice - Researching Intex pool purchase

[littlemisszoom]

Hi there! I've been stalking - ahem, reading - your forum for a bit now, but haven't quite found the answer to my query. We are looking at purchasing a less expensive AG, either an Intex Donut or metal frame. Max size will probably be 18 by 48, but I'm leaning more toward the 15 by 42, as we have little ones. Does anyone have opinions about which one is more favorable? I'm personally more into the donut, but I'm also concerned about Mr. Monkey (the 3 year old) scrambling over the side and flooding the yard.

Also, what size filter and/ or pump would you recommend, since the general consensus is that the included ones are rubbish? The 15 by 42 had a 1500 gallon pump, but aside from "bigger is better," I'm not sure what else I should look for. We're only looking to keep it for 2-3 years and plan on taking it down in the fall, if this makes a difference.

Thanks!