How to pick pump/filter

I've scrolled through the various posts and haven't been able to figure out an answer to my very basic question: what size pump & filter makes sense for my pool. Here's my setup:
30,000 gallon, inground plaster pool
polaris running off own pump
currently have 3/4hp pump and sand filter
one skimmer, 2 returns
equipment approx. 20 feet from pool, direct run pipes

Pump is making a lot of noise, and probably is near replacement. Sand filter (Aquatech Tagelus) has served well, and frankly I worry about environmental issues with DE. However, I can't read the model or specs on the filter (it's been too long outside). I believe at one point we figured out that it would filter the pool in 10 hours, if that helps at all.

I would appreciate an suggestions and recommendations from the wise folks on the forum. Thanks...