Hello everyone. We have always had a pool and I have always done all the cleaning, testing, etc. with no real problems. However, we just moved into our new home and am a little perplexed. The pool was built around 1989 and has a spa as well as a waterfall. Has not been maintained the best. So, I will be submitting some pics later that maybe you guys can explain a few things for me but for now one question. He has two pumps and two filters on this set up and the valves and piping all connected. One filter for the pool and waterfall is a diatomaceous earth type and the one for the spa is a cartridge paper type. Is this normal? Should two different type filters be on the same system? I took the cartridge one out to replace it and it was full of what I assume is diatomaceous earth granules. I have never owned one of those type filters so I will need to read up on it. But will I be safe installing the new cartridge filter and running the whole system together again? Thanks in advance for any help.