You do a great job of explaining things. The plumbing is always a barrier for me but I am learning more all the time! I need to break apart my ultimate two. I don't have velocity so I checked my impeller it's all good. Nothing lodged in there and someone from my quick club told me to switch it to researchulated and if the flow increases then that means it's an issue with maybe my media being impacted or really dirty, so this will be the first time that I've opened it up and I really appreciate your videos. I have added skimmers because of accessory submerge pumps that I have because I also don't think that the ultimate 2 is adequate filtration. I think I need more mechanical so I have a stainless steel box filter and then I just had a bog filter installed but it was very challenging. So I am trying to learn this stuff myself! I am very interested in the gravity fed system that you use almost exclusively I don't. I'm not sure what that is but I'm going to watch the videos and find out