I just bought a 13'x25'x4' Tuff Pool and need to figure out what pump to get and what size sand filter.

I plan on running the pump 24/7 because I'll have two 2x20 solar panels and because the pool will be used daily (mostly by dogs). The pipes running between the pump, pool, and solar panels will be less than 10' long as everything will be close to one another.

Three pool supply retailers recommend getting a variable flow or variable speed pump because they're energy efficient. After doing some research on this forum, it seems I may not have to get a pricey variable flow/speed pump because a 2 speed pump will suffice, especailly if it runs on low most of the time. Would it be better to buy the pricey variable flow/speed pump because they are more energy efficient than 2 speed pumps?

Second question: What size sand filter do I need? If I have this right, I think the surface area of the filter determines the hp of the 2 speed pump.

I thank you in advance for any advice.

Louisa