I have a 55gal food grade blue HDPE barrel in my basement and a 125gal in my kitchen area. Here is the set up I use. I use a regular garden hose to drain my tank into a drain in the basement and then connect the black hose on the pump to the garden hose fitting and pump it up my tank from the aging barrel. A 55gal wc takes me about 15 mins total using gravity to drain and the pump to refill.
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Be sure to use rigid hose on the intake side of the pump as the suction pressure will collapse a flexible hose. The outlet side doesn't matter. Hope this helps!