For the pump, ill be using this Amazon.com: Flojet 03526-144A Triplex Diaphragm Automatic Water System Pump, 2.9 GPM 50 PSI, 12 volt DC: Automotive
For the filter, i think I have an old "type C" pool filter laying around.
This is the water heater. CAMPLUX ENJOY OUTDOOR LIFE Pro BD158 1.58GPM...