Using AC unit run-off water with low pH and TDS

[Orchid Whisperer]

Zoren:

Don't use sodium bicarbonate to adjust pH for orchids or any other plants. The sodium is bad for them, and they will die.

As Camille said, you pH measurement is possibly way off if you are using a cheap pH meter, especially if you are not calibrating it to laboratory standards. pH meters that can be calibrated properly start at $200 minimum. Again as Camille stated, better to use pH paper, which is cheap, simple, and accurate enough.

If your air conditioner water is truly at a pH of 3.3 to 3.5, the easiest way to increase the pH is to mix it with municipal tap water, which is always maintained by cities at pH above 7.0. Usually pH of 8.0 to 8.5. Cities do this to help prevent pipe corrosion.

[Subrosa]

Contamination? Of course. Practically all water is contaminated to some degree. It usually blows people's minds when they first hear that completely uncontaminated water does not in any way, shape, or form, conduct electricity. It's only when contaminants dissolve that water becomes conductive. In any case, the amount of contamination required to drop what is essentially distilled water to a pH in the low 3s is tiny indeed. For fun, see how little of whatever pH up you decide on is required to bring the pH up to a more desirable level. And remember that you've been breathing in any contaminants that wind up in the water, short of traces of copper. Aluminum components will have an oxide coating that gives very good resistance to mild acids.

[Zoren]

, Thank you all for your advice, I will try adding 'tap water' to raise the PH of my A/C water, it seems to be the best and easiest way. As to the quality of my meters the ones I have were not cheap,but they didn't cost me $200 dollars (that's for sure). But, I will get myself PH paper. Thank you all again for your help and suggestions...Zoren

[rbarata]

You can taste the water to confirm any measurement error... the ph you've measured is as acid as something between orange juice and vinegar.

[Ray]

I suggest you try a pour-through experiment. You can start with a pot full of potting medium and no plant, if you're not willing to risk the plant:

* Water it normally and thoroughly with your "low pH water and fertilizer solution".
* Wait 30 minutes.
* Trickle about a shot glass full of known pure water over the surface and collect the runoff.

Test the pH of that, as what is happening in the pot is far more important than what you're pouring into it.

[Zoren]

Well members your opinions and suggestions are right on point, but, the one thing we (I include myself) forgot (another possibility)...weak and dying batteries. I decided to look at the batteries, well when I put them back the meter light went off, indicating 'Dead' (yes, made sure they went back in properly). Purchased new ones and the new readings are a lot different. A/C water PH closer to 7.10 PH with MSU fertilizer closer to 6.5 PH. The TDS from A/C is still 4-5 ppm. I have no more A/C water at this time. I'm going to Puerto Rico this afternoon, so I won't be running the A/C till I get back on July 2nd. I will do the tests again to see what the TDS and PH of the water is (without and with fertilizer). Until then I will be shutting down my computer about 2:30PM-EDT, so until then, comments are still welcomed...Zoren...

[SundayGardener]

After having collected, melted, and stored snow water this winter, I'm curious if you plan on using the water immediately, or on storing it?

I boiled my snow water before using it, but even so it would develop a film being stored. We have a dehumidifier and we've discussed using that water, but the receptacle tends to turn black inside where the water is, which also makes me wonder about storing water. I actually googled how to store collected water last winter and mostly just found instructions to boil and filter.

[Roberta]

If you can exclude light (a black plastic container with tight lid) you may be able to keep the algae growth (which is probably what you are seeing) under control.

[Zoren]

Members back from Puerto Rico (had a nice time). As for storing my A/C water I don't store much more than 5 gallons at a time. I use most of the water right away. As I have said before I collect a about 1.5-3 gallons per night and about the same when I use A/C during the day (I usually turn on the A/C when the temperature reaches 88-90 degrees F). I will be keeping an eye on the day time temperature because the room has reached 110 F in the summer (and it isn't August yet usually the hottest month in South Florida. As for the water turning color or growing algae, I haven't noticed any any changes at this time. I usually have to pour a lot of the water down the sink. When I have to much water and I have stored some of it I get rid of the stored water and keep the newer water. So far I have noticed a positive change in my plants since I started S/H growing, I see growth and flowering (I only started S/H about a month and a half ago. Thank you Ray for doing all the work in developing this way of Orchid growing. I was about to give-up on growing these beautiful plants, I hope that I can continue being successful...Zoren...

[Dumb chemist]

I guess I should add my 2 cents worth to this discussion:

The pH meters I have used in the lab have always been the ones with an analog or digital readout and with a pH probe and an Automatic Temperature correction probe (ATC). The meters were always calibrated with standardized pH calibration solutions. The meters were calibrated daily to ensue accuracy. Unless the pocket pH meters are calibrated just before use, I would wonder about their accuracy. pH test paper is accurate to a full pH. There maybe test papers that can go to a half a pH unit; but, I have not seen any. I would use the pH test paper first.

The use of A/C condensate water on Orchids is not a good practice IMHO. The condensate is in contact with the condenser coils before it enters the collection bucket. The coils are made of (pregnant pause) METAL. The metal is usually stainless steel which is made of iron and chromium. The water will pickup iron and chromium ions during its brief contact with the coils. What I would say is this: Would you drink the A/C condensate? If the condensate is not potable, would you use it on your Orchids?

Chemist joke:
Did you know that they found the universal solvent? The only problem is that they could not find a vessel to store it in.