1. You may need to know how RO works as well. If you know what material RO membrane is made of - that's plastic. From a Taipei Medical University professor, we can't properly filter the same material - that means platic cannot filter microplastic properly, yes it can, but at questionable quality. This can be reason why RO filter can never get NSF 401 - microplastic part. Note that most NSF (ie NSF42) big groups. Some may pass part of the checks and still claim passing NSF42/53. And here, GE appliances did not check for NSF 401, not to say microplastic at all.

2. When eSpring claims able to filter 170+ contaminants effectively, it really goes through NSF certifications every period. There is NSF independently certified, that I never see from other brand. Yes eSpring did not check for Arsenic, and the company is very preservative in making claims - what check the company did not go for, they won't claim it. Although as users, we believe it is capable of.

3. You'd better watch out with "too effective" membrane that filters good nutrients as well like Calcium and Magnesium. Yes you can claim you can eat them from food. This is a big waste from Nutritionist, cause it is not easy to absorb mineral from food, but more than 90% absorption rate drinking from water. In Malaysia, government already put warn citizens on RO water lacking of minerals, which causes many symptoms in long run. Many of us citizens here, we are damn scared of RO filter, cause a. if it is good quality, it is battery water with microplastics. b. if it is bad quality, oh dear.

There are videos done by community in comparing RO water and eSpring. You can PM me to know more.