This will make ya laugh, I use a Koi fish pond water kit's Ph meter, the darn kit cost $134 seven years ago. It tests the water down to a ph of 5.0 and for something like 7 different tests and chemicals besides the O2 content. I gave up playing with it on the fish and brewing after a couple years and use the well water as the well is 7' away from the pond plus the water has the perfect Ph and temperature for the Koi. Some of the fish have been around when I was a kid now i'm a 56 year old kid, must be doing something right for their health. For brewing I lower the Ph with my little cap, one cap per/5 gallon batch, 3 caps for 15 gallons. Straight and simple.
I would ask your water district for a report on the water they serve to you, it should be rather elaborate. The crap in my tap water will kill the Koi and tropical fish hence brewing with natural, fresh rare "islander water".