vacuum lowers pressure and drains pump trap

It doesn't matter if I use the Ranger auto vac or hand vac brush, I fill the hose w/ water to get all air out, but when hooking them up to the skimmer, the pressure goes from 18 to 10-12. Suction is poor, the auto vac is sporadic whether it keeps moving or not, and the pump skimmer basket/trap drains fairly quickly. Water is still sucked through, but not as fast as it is drained.
Pool is ~7 yrs old. We've always used solar panels before and this year switched to the solar ring things bc the panels do not hold up. 1 1/2 hp pump, 27' round AG 4' deep. There is a slight leak on the bottom of the pump trap puttied to be a steady drip. Don't know if/why this would affect the vacuum though. Any suggestions appreciated.

Disconnecting the solar rings didn't help.

I'm sorry. I wish I could you help you with this, but don't know what to suggest. Hopefully someone will come along soon who can.