Bests & Worsts Reviews from Amazon

Being the anal retentive consumer I have always been, I previously purchased a Professional Digital TDS Water Quality Test Pen (TDS&EC - Health Metric) prior to purchasing my first reasonably priced household water filter. I live in Phoenix AZ. Googling the majority of city tap water information on quality universally suggests that the average quality of city tap water is between 250-350 ppm(parts per million particulates) with an acceptable maximum of 500 ppm. My Phoenix tap water measured out at an average reading of 520-540 ppm! Holy crap! I was immediately inspired to order a water filter device. Based on 4-5 star reviews, as I base all of my uncountable Amazon purchases, I originally chose a PUR household water filter. After repeated testings of the filtered water of the PUR I was very disappointed to see only an average of a 20-45 point reduction from raw tap water readings of 540. I could only assume that those reviews were not empirically tested with water meters and judged by taste and other vague components of value. I returned the unit in spite of the fact I received email admonitions from the manufacturer about the reduction of harmful things like lead and chlorine etc. Got it! Those reductions were already assumed. It's all the other crap I wanted to see reduced. I returned the PUR unit and decided on the next equally reviewed and economically priced filter named Brita. Lo and behold, in addition to zapping the regular bad stuff like chlorine and lead etc, I wanted to see a substantial reduction in ppm which I could assume were unaccounted for and unnamed particles of unhealthful origins! Hallelujiah, my 540 ppm Phoenix raw tap water reading was reduced by the Brita to virtually half of its original content. Consistent filtered readings of 230-265 gave me the confidence I was looking for that my filtered water was indeed filtered and hopefully way more healthy for my liver, kidneys and total bodily functions! Update June 25, 2017: I am in the middle of the useful usage period of three months of the first of my three pack of Brita filter replacements. It occurred to me that there might be a difference in performance from one filter to another. Their original filter as noted was satisfactory. I was not expecting anything earth shattering from a major manufacturer such as Brita...but I was shocked to see otherwise on my recent retesting. Again using my TDS&EC Health Metric PPM meter I again tested distilled water prior to testing the replacement Brita unit. Distilled water properly indicated a reading of '000'. My Phoenix tap water tested consistently as it always has at an average of '540' PPM which is of course terrible for city tap water by the internet research previously noted. The replacement filter was shockingly different from the original filter provided from the newly purchased Brita pitcher and reviewed above. Three separate and consecutive tests yielded the same shockingly different results. The replacement filter, only one month into its expected life of three months read my tap water at an average of 410 PPM. Phoenix tap water reads a dreadful average of 540 while Brita filtered water is logging in at an average of 410!?! I am officially disillusioned with the efficacy and efficiency pronouncements of the Brita company. Obviously I had to seriously downgrade my stars for this item. I will not be ordering Brita filters again.