Help me figurure out my issue (4/19 New Sump?)

This is where I am at:

Temp rising to 84, need to get those fans installed.

Salinity: 1.025
pH: 8.25
Calc.: 380
All. 4.5 meq/L or 12.5 dKH

I guess I still need to do water changes to get alk. down. Frustrating.

 

I found a sump online that's about the size of a 20 gallon aquarium. It has 3 compartments and is commercially made box. It comes with a float switch and all of the plumbing.

The price is $50. Is that a good deal?

I would need to buy:

1) overflow
2) return pump
3) sock
4) return nozzle
5) small pump for top-off
6) chaeto
7) Media for phos. reactor (what should I get?)
8) Clip on flood Light

Anything else?