Water Softeners and Air Filtration Systems - Acidic R.O. water challenge

I've recently started gardening and was told plants do very well with R.O. water,so I tried it. All of my plants begin to show signs of P.H. overdose,(burned leaf tips,blotching ect.) and eventually wilt and die after about one month of strong vegitative growth. I tested the P.H. of the R.O. water and found it was a FOUR!!! Waaaaay to acidic! Any way, what I want to know is: Why is R.O. water more acidic that regualr city tap (7 P.H.)? Any thoughts are appreciated.

It is unreasonalbe the think thar you RO is actually dropping pH from 7 to 4 unless your measuring device is faulty or you are adding mineral acids to the water.

Please measure your hardness (calcium carbonate) before the RO.

RO will drop pH somewhat as you are removing hardness minerals but not down to 4.

Solution. Pass water through a calcite (limestone chips or southern marble) or similar media to raise pH. You may need sodium hydroxide if the pH is really way down to 4. Contact time (or solution strength) will depend on flow rate and actual pH.

Andy Christensen, CWS-II