I have a Grundfos pump that I have not tried yet in my solar drain back system. I am wondering if this pump is self-priming

Along with this question, I have another question on where to locate the pump. If it is self-priming, it would seem to me that the
pump should be located above the water level of the solar collection tank, to allow complete draining when off. Is this correct thinking?

My system: two homemade solar collectors made from heavy aluminum flashing over pex-al-pex pipe, 80 square feet. Collectors angled at winter angle, because of possible overheating, permanently. Lexan covers and 1" polyiso insulation on the back.
Insulated tank, 180 gallons, with 150 feet of 1" pex pipe in the water as a heat exchanger. Thermistors in tank, both collectors, and outside air. Homemade temperature controller with graphic screen.

Tests have indicated that the BTU output of the collectors in series is over 15,000 BTU/hr in the early afternoon. Temporarily using
cheap AC submersible pump from Lowes.

My first PV system is also now installed, 2.6kw 12 Canadian solar CS5-230P, 3 BP 150W panels, Fronius IG-Plus 3.0-1. Producing
14-15kw per day.

First post!

Take care,

Moultrie, GA