This is a grohe faucet. it has a pullout spray head. i had to replace the fitting at the faucet end of the hose due to a leak. I also replaced the cartridge because the water pressure was low. I also clesned out the sprayer head and cleaned out the lines by running water through the hose into a bucket. now, after 2 weeks the water pressure is again low. i cleaned out tye spray head again but the water pressure did not improve. whats my next move?