tap water results

One of the things you will find is that many water supplies have had their pH raised above neutral, so as to stop the water from reacting with/dissolving metals in piping, especially lead. So, absent a water softener before the sampling point, it may be that the water company has added something.

Carbon filtration probably won't do much for TDS. It is more for organics in the water.

Hopefully Ray will chime in here.

 

I am certainly no water quality expert either, and that relatively high TDS for a relatively low hardness thing caught my eye, too.

7.5 pH is OK, but I agree that a bit lower would be better. Any acid will reduce it - citric acid is good as it actually functions in plant metabolism, but ordinary household vinegar will work, too.

Carbon will do nothing for TDS reduction, and aquarium chlorine "removers" chemically tie them up, but don't actually get rid of the,.

 

Reverse osmosis. That's what I do. Even though I'm not Ray.

 

The only things that can do that are distillation, deionization, ultrafiltration, or reverse osmosis. Another alternative, although expensive in the long run, is to purchase purified water and use it to dilute your tap water.

 

Back in my African violet days, I experimented with raising my water's pH by using vinegar. It did a dandy job, but 15 minutes later pH was back where it started. It's harder than it sounds to raise water's pH for any meaningful amount of time; you'd do better working with your potting medium.

 

How does acetic acid raise your pH? Is it a proton exchange between a carbonate cation?

 

It's an acid. It lowers the pH, not raises it.

 

Oops, sorry; had a dyslexic moment there.

 

That's what I thought. I read some whacked out things regarding pH that don't make sense on an equilibrium equation. For example lemons being alkaline? I give these things the benefit of the doubt often and try to reason through before dismissing. "Is the conjugate to that strong?" Etc.

 

I don't know what you're reading, but stop! Lemon juice will lower the pH as well.

I think that a major factor most folks ignore is that the pH of the applied solution is not that important of a factor. It's the pH of the medium that is, as that's where the plant lives, and both the potting medium and the plant itself affect the pH.

The thing to do is measure the pH of the "pour through."

1) Water the plant thoroughly, using whatever solution you normally apply, and let it drain completely.
2) Wait 30 minutes, then dribble a small amount of pure water (RO, DI, distilled) over the top of the medium - just enough to drain through - and catch and test that pour-through.

 

I've also heard you can soak some of your medium for 30 min. or so, then strain off the water and test that. Toe-may-toe, toe-mah-toe, I suppose.

 

The only potential problems with that are that the plant doesn't live in the soaking solution, it lives in the solid medium, where the plant itself can affect that as well, so soaking the medium tells you nothing about that, and the excess soaking solution may interfere with the overall reading.

If the standard pour-through method would give a pH of 6, and you soaked that medium in a large volume of liquid of pH 8, I doubt you'd get an accurate reading out of that solution afterward.

 

DPfarr, I think you might have been reading stuff about the acid alkaline balance diet, which is basically a bunch of pseudoscience . That the only time I have seen anything like you mention.

 

Oh I realize it's people who've never had a gen chem course.