The soil PH is what needs to be kept in check not the water. I see your system is dependent on the water PH. That is a sure way that plants get the nourishment required to obtain the outcome to the perfect flowers you have hybridized. Do you show your zinnias at floral shows ?
In the Oregon coastal area the average rain fall is 44" per year. It's acid rain and causes moss to grow on everything even between your toes in ya stand in one place longer than a few minutes. Yearly I measure the garden and amend the soil to bring the soil PH up between 6.5 and 7.0.l use a soil PH tester.
