pH normalization of tap water

[Rougarou]

So I have crappy tap water. The water report states a pH of 8.77. I've almost lost a few houseplants before I caught it. For the past week i've been running a little test. Results were obtained with pH strips. Suspect results confirmed with liquid drops. I have a meter on order from Amazon.com. I thought I had already ordered one but when it came in I saw that it was not a pH meter, but a TDS meter. D'oh.

Results
Baseline (straight out of the tap) 7.5
after 24h dechlorination 7.5
addition of 1/4 tsp vinegar per 1 gallon 7.0
+24h 7.0/7.5 (2 test methods, strips/liquid)
+24h 7.0/7.5 (2 test methods, strips/liquid)

Here's my issue. I'll be starting my first cannabis grow within a month. Nutes are FF tiger bloom, big bloom, and grow big. Soil is Ferti-lome Ultimate Potting Mix. Will my girls think the pH is too high for the water without being pH treated? Or will the soil+nutes combo drop it enough to where I won't have to worry about it?

My venus fly trap seems to like the new water. It couldn't stand on its own this morning and to my pleasant surprise it was perky as heck when I checked on it about an hour ago.

Also, I've read vinegar is a poor substitute for pH Down because it's only a temporary measure. However, my results disagree with that statement. Thoughts?

 

[SeaMaiden]

The water is likely very hard, but via what type is an unknown. You should also be able to get a water report that states general and carbonate hardness levels, as well as other parameters. It's the hardness that's an issue, not "just" the pH, you see, especially if it's due to carbonate hardness.

The problem with any pH adjuster (except perhaps the strongest) is that hardness, carbonates buffer the water against pH shift. Vinegar is a very low pH, but its effects are essentially counteracted by the carbonates, and bammo, up the pH goes again.

Filtration is one way to reduce hardness, and then mix back with tap to gain pH stability. Type of filtration and its efficacy varies. You can try boiling small amounts of water and taking only the more clear water at the top, get a reverse osmosis filter, or use a combination carbon filter to some good effect.

If you find the pH was shifted, I'll suggest that the hardness is from other minerals besides carbonates (typically CaCO3 and MgCO3, calcium & magnesium carbonate, respectively), or that the water isn't all that hard.

I would also call into question the accuracy of the testing methods or products in the first place. Is what you're using known or proven to be accurate? Or was it something you picked up at a hardware store or similar? That makes a difference.

 

[fungzyme]

You can try boiling small amounts of water and taking only the more clear water at the top,

Maybe I'm misunderstanding this, but what is boiling supposed to do? If the stuff you want to remove is truly dissolved, boiling will only concentrate it (as the water vapor leaves as steam) and determining a 'more clear layer' of clear water (if possible) is not going to be of any practical use.

If the OP already got a tds meter by mistake, I'd use that to test your tap water to see what the ppms are. That might at least give an idea of how much RO or distilled water to mix up with your tap water (if you go that route). And IF the tap water ppm isn't off the chart, the nute/water mixture pH is what the plant cares about and there are simple ways to get that where you want it.

 

[SeaMaiden]

Boiling is a method by which another type of hardness-temporary vs permanent--is determined. I reduced the hardness of my well water by over 40% by simply boiling for 7 minutes. A layer of mulm, if the hardness is temporary, is created and easily seen at the bottom, allowing one to easily pour off the remaining water.

 

[Hüsker Dü]

Any ideas what a condenser dryer will do to the water?


HD

 

[fungzyme]

Boiling is a method by which another type of hardness-temporary vs permanent--is determined. I reduced the hardness of my well water by over 40% by simply boiling for 7 minutes. A layer of mulm, if the hardness is temporary, is created and easily seen at the bottom, allowing one to easily pour off the remaining water.

Thanks for the info. Is that mainly for well water as opposed to municipal water, and is it the iron salts or something like organic matter? Sorry to hijack, but hope to be moving to a well water location soon, and somebody else might find this useful too.

 

[Rougarou]

The water is likely very hard, but via what type is an unknown. You should also be able to get a water report that states general and carbonate hardness levels, as well as other parameters. It's the hardness that's an issue, not "just" the pH, you see, especially if it's due to carbonate hardness.

The problem with any pH adjuster (except perhaps the strongest) is that hardness, carbonates buffer the water against pH shift. Vinegar is a very low pH, but its effects are essentially counteracted by the carbonates, and bammo, up the pH goes again.

Filtration is one way to reduce hardness, and then mix back with tap to gain pH stability. Type of filtration and its efficacy varies. You can try boiling small amounts of water and taking only the more clear water at the top, get a reverse osmosis filter, or use a combination carbon filter to some good effect.

If you find the pH was shifted, I'll suggest that the hardness is from other minerals besides carbonates (typically CaCO3 and MgCO3, calcium & magnesium carbonate, respectively), or that the water isn't all that hard.

I would also call into question the accuracy of the testing methods or products in the first place. Is what you're using known or proven to be accurate? Or was it something you picked up at a hardware store or similar? That makes a difference.

I'm a step ahead of you, my seafaring friend. I got the water report first; that's what made me start stressing over pH.

Water report

Chloride < 10 mg/L
Hardness, as CaCO3 0.6 mg/L
measurement temp 19* C
Alkalinity as CaCO3 138.0 mg/L
Fluoride 0.1 mg/L
Sulfate 2 mg/L
pH 8.77
iron 0.01 mg/L
sodium 64.5 mg/L
potassium 0.7 mg/L

testing was done with aquarium-grade pH strips and liquid, on my end. The above results are directly off the lab report, done by the state Dept. of Health.

 

[whodare]

Acid injection is one way to balance carbonate hardness. Use nitric acid in veg and sulfuric in flower...

When you get your water to 4.5 ph all the alkalinity has been neutralized...

Dizzlekush has a thread in the advanced forum I believe that covers what I just told you but in more detail...

 

[SeaMaiden]

Roug, looks like it's pretty much only that CaCO3 (aka calcium carbonate) that's got the pH buffered. And that's exactly what I would expect from a muni water supply, they have pipelines to keep going, potability issues, etcetera. I wonder if they have to add it back in.

But, converting that mg/L to a value I can understand, it's rather soft water. That level of CaCO3 = 1 degree of KH (German, or carbonate hardness). I consider that to be very soft, low alkalinity water, and I wouldn't expect that coming from muni-sourced pipelines. I think that explains how and why it was so easy for you to shift pH.

Thanks for the info. Is that mainly for well water as opposed to municipal water, and is it the iron salts or something like organic matter? Sorry to hijack, but hope to be moving to a well water location soon, and somebody else might find this useful too.

Any water. I only relatively recently learned about these types of hardness, and I learned it through Wikipedia. I don't recall what types of minerals cause temporary vs permanent hardness. I seriously doubt there's organic matter making its way into our well, though, as it's quite deep and required drilling through mostly all rock.

 

[Rougarou]

SeaMaiden: Yep, the water's pretty soft. That's odd because I have some experience working with the aquifer that feeds this area (environmental scientist-in-training) and this aquifer is typically hard as a rock. It's a stone cold mutha to keep toilets clean in this town.

I finally ended up saying "hell with it" and ordered some pH Down. I guess an investment in the near future will include a water barrel, stand, and spigot. *sigh.*

I miss the Mississippi. Back when I was doing my water treatment gig we pulled our water directly out of the river and we constantly won awards for best water in the southeast.

 

[VerdantGreen]

i have used tapwater pH 9 or nearly that for years on my cannabis.

i just use citric acid as pH down which is also good for organic grows.

 

[Hamburglar]

Just make sure to NEVER use organic acids for hydro grows.