I recently purchased a house which has a whole house water filter installed (Purwater FHT-34V). I changed the filter which looked like it hadn't been changed in years. The filter has a valve in the lid and I am looking for help in understanding how to know when the filter is in "bypass"' "off" and "filter" settings. There is a little tab on the lid which may or may not indicate the setting. When I changed the filter the little tab was over the "bypass" setting and water was leaking out so I had to shut off the main water valve to change. Just curious if anyone has had experience with these filters as I haven't been able to find any manual. Photo attached showing way I found filter housing.