Lots of things to effect how you should clean your filter. Tanks are all different so what one can get by with may not work for another. If you are stocked pretty heavy in a newer setup and do a hard cleaning of a lot of the media, you may see a spike while another that is lightly stocked may get away with cleaning in tap water.
For me, the safer way is the way I want to start until I see what works for me and my filter. New bacteria are not fully settled in and seem to be tender. The safe way is to not clean a canister on a new tank quite as soon as you might later. Leave the sleeping dog lie? Then when ready and really needing it, go gentle until you get the feel of what is acceptable for your tank. I have a large bucket and formed a strainer to rinse the media. Sine you remove some water in the filter, I have to top off after a cleaning so I just go for taking some tank water in the bucket, swish and squeeze the soft stuff, rinse the hard stuff and replace any media that is worn out.
If it is the U-tube that I think of, it is full of bad ideas and planning. He rinses in tap without explanation but that is not the bigger issue that I see. Does he also treat his electrical as if he will live forever? He is just so cool that he might kill himself!
Treat the bacteria like the friends they are, clean the impeller like you would want it to last and don't trip over the electrical cords?
Later when you get a better feel of things, you can do all kinds of risky things but until you know, it is safer to treat the little friends nice.