I won't have time to work through this for a day or so, since I have to look up your equipment.

A couple of quick points:

1. Maintain your pool with Walmart 10% pool bleach, if there's adequate stabilizer. Or, with Sams Club dichlor (box of 24 x 1# dichlor bags) if your stabilizer is low.

2. Don't swim.

3. Don't buy Chinese engineering.
[ The design quality is variable, but the QC consistently sucks, with probably 10% of even GOOD products arriving defective. Worse, with long-life equipment (like pool pumps) Chinese manufacturing NEVER produces durable products. ]

4. Check your pipe circumference again. With Schedule 40 pressure rated PVC, 2" pipe is 2" ID, with an actual OD of 2.375" [circumference = 7.5"]. 1.5" pipe is 1.9" OD [circumference = 5.7"] It sounds like you have 1.5" piping, and ought to be looking at 0.75 HP pumps. The upside of this is that the right pump will literally save you $1,000's over the next decade, assuming you operate year round. So it's worth taking your time, and getting it right.