Review on APEC Water Systems FILTER MAX ES50 Replacement by Bohyun Hansen

Of course these are high quality OEM filters. A little effort. I wish the instructions were better. A sheet of instructions with not-so-good little numbers was ok, but it took a lot of effort to understand. Requires a key to open housing for 3 pre-filters. This key was included with the system. If you lost it, you should buy it! Replacing the 4th filter requires a 12+ inch wrench to open the housing. When installing the system for the first time, I manually locked the case; but after 4 years of use the lid became very tight. I had to go to Home Depot to buy a 12 inch pipe wrench which was barely enough to get the lid open. Once I opened the lid, I had to use needle nose pliers to pry the filter out of the housing. I bought a set of filters on 09/13/2019. Reviewers in 2018 reported a missing QC connector (i.e. 3-way tee), I didn't have this issue. I received o-rings for 3 pre-filter housings. But I didn't install them because I noticed that everything was fine with the existing O-rings. I mean after 4 years of use these o-rings are still very good. However, the manufacturer recommends replacing them. I'll do that in a year when I change the pre-filters. There is a lot of water in the filters or housings. Therefore, be sure to place a couple of thick bath towels under the system before changing the filters. After changing the filter, be sure to drain a few gallons of filtered water until the dark charcoal is gone. QUESTION: I have a question. If anyone knows the answer, please add a comment. Do I need to repressurize the tank if I replace all 5 filters?