Filter housing has low pressure, won't operate the kreepy krawler

Glad to be here, and I have a simple issue that seems to be confusing. I had an inground pool built in 2007 and all was great. In 2014 I replaced the motor as the old one seemed like it either had a bent shaft or something, very noisy. I put a new motor, impeller and seal kit in it as well as cleaning the filters after draining and refilling the pool. Still all was great after that, three months later the filter pressure dropped where the Kreepy Krawler would not move around the pools floor to keep things clean. The strainers have always been cleaned a few times a week and the pump strainer was always maintained. I once again cleaned the filters but they didn't seem too dirty as I keep a solar cover on the pool when not in use. I still can't get my filter housing pressure up enough to run my cleaner and it's not the motor either, both motors produce the same pressure. Any ideas for you guys would help.

Charles