Bigsplash,

You will get a more accurate head calc using the PSI from your filter. If you also have a vacuum guage (easily bought at Sears), you can also get the suction head too.

Total Head = Filter PSI * 2.31 + Pump Vacuum (in. mg.) * 1.13

Use 8 in. mg. if you do not have a vacuum gauge as a good guess.

Solar panels are difficult to determine the head because there are too many factors. However, a worst case would be an additional 10 PSI on you filter pressure.