I have the Hayward Power Matrix 2 speed 1HP pump. At low speed the flow is fine for my heat pump. If I also send water to the solar panels then I am on the border with respect to flow rates. This would be at low speed. If I start the pump off at full, turn solar on and then switch to 1/2 speed it almost all works ( heat pump, solar, but not salt). Remove solar and then at half speed both salt and heat pump work. Really nice pump but I miss self priming and it is noisy at full speed ( well no worse then others but it is silent at 1/2 speed).