i don't think the JH018 is made correctly
1st video shows a high water level so that you can see the water going up the drain when i pull
next 2 videos show different water level but still pulling up the drain, but less
last video is where, in my opinion, is where the water level is ok as it is very slightly pulling up the drain
imo i think they made the prec to low on the stem as it is almost even with the return
and the drain hole needs to be bigger
need any other pics or video just ask
edit:imho, if someone else had posted this i do not think i would have got it