I originally installed my pump at the same height as the top of the tank, and with the tank half full, it would not prime itself. The tank is about 18" tall, so it would not pull water up 6" or so. That may give you some idea of it's pulling capabilites.
After I primed it by pulling a vacume on the discharge with my mouth, it pumped. However, after being turned off for a minute or so, it would not reprime itself.
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