Tap water quality and organics

Hey everyone,

First time organic grower here with a couple questions about my tap water. Here in my neck of the woods, the tap water comes out with a pH of about 8.5-9 and a total dissolved solids concentration of about 20-30 ppm (LOW!). It's also got chloramine in it, which I remove with a Small Boy filter (w/ the upgraded catalytic carbon). When I brew compost teas with this water, I don't adjust down the pH. I simply add a cup of worm castings, a few tablespoons of guano, 5 or so tablespoons of blackstrap molasses, and maybe a little Earth Juice Meta-K and/or Earth Juice Microblast to my paint strainer "teabag" and bubble it. After 24 hours of bubbling, I've got a frothy brown soup with a very pleasant, sweet, earthy aroma, and a pH somewhere between 6 and 7. The plants LOVE it, full strength.

My question is... When I use plain water between compost tea feedings, do I need to worry about the super high pH (almost 9) given that the ppms are so low? The dissolved solids are so low that my Oakton pH tester can't even read it properly (readings just bounce around between 5 and 9). What do you do about pH of your plain waterings? I see that there are organic options for pH up/down, but I read all over the place that you shouldn't mess with pH when doing organics.

So what would you do?

Thanks for any help!

Your water may be hard and that's why the ph is high but, r.o. water should lower it. Have you ran it thru an r.o.?

Sorry you said you do. That's weird it still comes out high after the r.o. huh?

[h=1]Is the pH of Pure Water Really Lower than Tap Water?[/h] This question is answered when you understand the equilibrium relationship between CO[SUB]2[/SUB], HCO[SUB]3[/SUB], and CO[SUB]3[/SUB]. In a closed system, the relative amount of each of dune compounds vary with pH. At lower pH levels, CO[SUB]2[/SUB] is the predominant species. HCO[SUB]3[/SUB] is the predominant species at mid pH levels, and CO[SUB]3[/SUB] is present at higher pH levels.
Since RO membranes will reject dissolved ions but not dissolved gases, the RO permeate and RO feed will contain roughly the same amount of CO[SUB]2[/SUB]. The HCO[SUB]3[/SUB] and CO[SUB]3[/SUB], however, are often reduced by 1-2 orders of magnitude. This upsets the CO[SUB]2[/SUB], HCO[SUB]3[/SUB], CO[SUB]3[/SUB] equilibrium that was established in the feed. In a series of equilibrium reactions, CO[SUB]2[/SUB] will combine with H[SUB]2[/SUB]O driving reactions similar to that shown below, until a new equilibrium Is established.
To summarize:
The new equilibrium will always result in a lowering of permeate pH if there is CO2 gas present in the feed water.


The pH drop is usually largest for waters with high amounts of alkalinity or HCO3.
When there is very little CO2, HCO3, or CO3, there is a very small pH drop observed in the permeate.
Therefore it is not true that reverse osmosis filters will always reduce the pH level of water to a noticeable amount. The pH difference after the RO depends on the composition of your input water source; depending on whether you have large amounts of gases such as CO2 in your local water supply. If you are concerned with the pH of your drinking water, you should avoid guess work and get your water tested with an accurate pH tester meter (avoid those $10 paper testing strips, which are very inaccurate with pH readings). If you see that your pH is below 7 with a good amount, you can consider putting a pH increaser filter as a final stage of your reverse osmosis system and correct your acid water problem easily.

Found this information surfing. Guess it depends on the composition of your water.

That's an interesting read, but not exactly applicable. Thanks for passing it along, anyway.

My Small Boy filter is not an RO system. It has a "pre-filter" to remove sediment, and then a catalytic carbon filter to adsorb chlorine and chloramines. It doesn't have any measureable affect on the pH of my tap water.
I know hard water's not the issue (20 ppm is actually really low for tap water).

Found some info about my tap water. It has an alkalinity of 18 mg/L as CaCO3. This is VERY low, meaning that my water has very little ability to resist pH change. This makes me think that adding my 8.5-ish pH tap water between feedings won't be any problem. It should very quickly stabilize to the pH of my soil, which is being moderated by the microherd and dolomite lime.

But, with such a low dissolved solids content, it seems like I might run into cal/mag issues...

If you have added dolomite lime to you soil mix, no worries about the pH going in, or cal/mag either.

Just that simple, easy and cheap.

Wet

I filter my water through a Small boy and add it with the Bio Canna line. I also add lime and use Cal Mag about midway through flowering. I never pH. I actually was at first, but then when i stopped, I actually started doing a lot better.

is the small boy setup good enough at filtering to handle nasty city water in SOCAL? I was thinking about taking the plunge and ordering the htg supply pure 100 RO system but then I wasn't sure how high my water pressure is....?

you could try purchasing a DI filter which will attract the ions and help remove any of those solids that are making your ph level so high...

The municipal water source (East Bay Municiple Utility District) adds sodium hydroxide and calcium hydroxide for the sole purpose of raising the pH. It's a strategy they use to minimize the amount of lead that leaches from lead pipes in old homes. Other than the high pH and the chloramines, the water is EXCELLENT quality. It originates in Yosemite National Park, flows to Hetch Hetchy res, then straight to my tap (more or less).

intensive said:

is the small boy setup good enough at filtering to handle nasty city water in SOCAL? I was thinking about taking the plunge and ordering the htg supply pure 100 RO system but then I wasn't sure how high my water pressure is....?

Click to expand...

I would say yes. I would be sure to get the KDF85 Carbon Filter that is an optional buy. The extra filter is for the Chlorine and Chlormines. My city water is actually very high quality, (Not in CA,) it just has chlorine and chloramines. When I added the filter, my microbes thanked me with a 25% increase in yield. (disclaimer: there were several reasons that this happened, but one of the biggest ones was the addition of the water filter and a 55 gal drum to store and aerate water with air stones. I bought one for my buddy for his birthday, and he also had great results after, and many issues we were having cleared up.)

And yes, So Cal gets alpine water from Hetch Hetchy. I grew up around there. The water was always of great quality. I remember drinking out of the rivers as a kid and remembering how pure the water tasted.