We've started the SLAM and everything was going well. Last night we powered down to clean the cartridges. When we fired up the system again we found that we had lost suction from the pool pipes. We have a spa as well but when we switch the valves to draw from the spa it works perfectly. Back to pool it pulls then drops to low flow. There is some water pulling but not the flush of water that we were seeing. It then flows at a low rate for a few minutes then kicks back in and repeats. Help!