I have an inground pool/hot tub. Both the pool and hot tub are level to eachother with a flowover. I have a DE filter - clean. 1 1/2 hp single speed pump. No booster - never needed. Recently, the hot tub dramatically slowed down on bubbles. PSI is stable when draining from either pool or spa. When water is returned to the pool - PSI stays the same. When it ONLY returns to the spa - it jumps by 10PSI. Jets in the spa have been checked and cleaned. There was debris from a deteriorated DE filter pad clogging the individual jets. Suggestions?