I wont be of much help on this bc I have a 2006 Pace Arrow, BUT, we had the same problem!!!! I took it to Wade's RV service center and they flushed / emptied the entire system numerous times. Filled it and continued to allow water to flow in (like you would at an RV camp site connect to water) and then had the empty or release clean out tubes open to drain everything. Then added some enzymes and flushed again. We were there doing this for 2 hours. It worked..... Hope that helps.