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Water quality question

Posted by maple_grove 6 (My Page) on
Mon, Apr 2, 12 at 13:56

Hello all,

I'd like to ask you all a question about water quality. By way of background, I want to try out some of the ideas discussed here for fertilizing (the "weekly weakly" method) and as a first step I got a TDS meter so I can keep track of what I am doing. Taking a look at the measurements for my tap water raised some questions in my mind.

My well water goes through a water softener. I have no choice about that and no real option to remove it without buying a whole house RO system. My untreated well water has some low level of iron such that w/o the softener, the water turns things red (toilets, anything that gets hit by the sprinkler...). I don't have the result in front of me, but from what I can recall, the water test showed high single digits ppm for iron, calcium, etc. I have been using this softened water for container plants/lawn, etc. for years and I've not noticed any problems (FWIW).

So I got the TDS reader last week and my readout is ~130-140 ppm, not too bad, right? Now for the questions. Since the water passes through the softener, does all 130 ppm necessarily consist of Na and Cl? With respect to Na and Cl, how much is too much (I know that none would be best, but when should I start to get worried?) As I said, I plan to use the "weekly weakly" fertilizer program, and preliminary testing shows that the total TDS will be ~300-500 ppm. But I'm curious about whether my sodium and/or chloride is (excessively) problematic. Again, this is mainly for curiousity since I'm not in a position to be able to do anything about it right now.


Follow-Up Postings:

RE: Water quality question

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Mon, Apr 2, 12 at 14:27

I think ion exchange systems are always going to be a problem - and most of the DS is going to be Na or K, depending on whether you're using NaCl or KCl. Can't you 'T' off of the supply line before it hits the softener & put a spigot, indoors & out, off that line - or connect a hose to it?


RE: Water quality question

Thanks for the suggestion, Al. My fear though is that if I tap off of the supply line, I'll be back to the water that gives the red residue. You'd be surprised what ~10 ppm Fe will do over time.

Several years back I looked into switching to KCl for the softener, but it was about 5 times as expensive as NaCl. I go through a lot since I have >1 acre of lawn under sprinklers. I actually listened to the sprinkler guy at the time of install and I went to the effort of replacing my softener with a larger, more powerful model. This one isn't on a timer, but runs through its refresher cycle as needed based on water usage. It'll run two or three times from October until May, but then 3-4X/week during the summer. As a result, I never made the switch to KCl.

Too bad the plant staging area is on the other side of the yard from the house, or I could go for the rain barrel solution. In fact, I just got a sealed 30 gal barrel to store my irrigation water in (from the hose), so that it can sit for long enough to equilibrate thermally before I use it for irrigation.

RE: Water quality question

Agreed. Although your native water has calcium and iron, the plants can use those. Sodium is really bad for your plants.

Have you thought about using rain barrels, at least for summer? My rainwater is about 40-60 ppm and pH6.0. Plants love it. I wish I had it year around. May have to build an underground cistern.

RE: Water quality question

Sorry, your post wasn't up when I was replying. If you can make the rain barrel work, that would be your best bet. Good enough for plants, anyway. Not sure you'd get enough for lawn watering though, you'd need a huge roof for that.

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