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Tap Water and TDS Questions

Joined
Apr 29, 2018
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I recently ran out of Distilled Water and since I cannot drive, I decided to test and see what my local tap water levels were. Here's some of the results:



TDS (Membrane Solutions TDS/EC Meter):
-50 ppm - 64 ppm
(n=6) *denotes how many times the water was tested with the TDS meter.



PH (using Aquarium Pharmaceuticals Freshwater Master Test Kit):
-6.8
(n=2) *denotes how many times the water was tested with the PH indicator solution.



Chlorine (ppm) --> Alkalinity (ppm) --> PH --> Calcium Hardness (ppm) (using Leisure Time Spa & Hot Tub Test Strips):
-1.0 ppm at 9:00 PM last night and 0.5 ppm at 12:30 PM today (this is from the tap water I've stored in two used distilled water jugs)
-40 ppm at both times I tested.
-6.8 at both times I tested.
-100 ppm at both times I tested.
(n=6) *denotes how many test strips used.



I hear the horror stories of people using tap water on their CPs, but I was wondering if this water would be acceptable for the tray method with H. Purpurascens, D. Spatulata and a variety of Nepenthes? Will using this water via the tray method lead to salt accumulation, or is that threat not as prevalent at my current TDS? I'm also going to attach some data of my local utility board's 2017 water report to show a few extra values I could not test for. Thanks for the help, and Happy Late Thanksgiving!
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If I'm reading your dada right you total RDS is 140pp. That would be too high for most CP. However, Neps have been known to tolerate higher TDS than other CP. You could topwater with the tap with a good flush on them every cuple of weeks. From you coment about not being able to get out leeds me to beleev you have a hard time leeving you house. If im corect on that you may want to invest in an RO. It would make things easer for you.
 

adnedarn

I'm growing CPs in the Desert of Tucson, Az
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I would use that water rather than letting those plants go bone dry for any length of time, but I wouldn't use it long term.

Using the tray method for water with ANY minerals in it will build up over time, the question is how fast. (This is an example- not anything exact just to explain what happens) Imagine you put 1million parts into a cup, 100ppm [parts per million] of those parts are minerals... When the water is used up and evaporates, the minerals are still there. So next time you add water, you add back in 100 parts of minerals along with the 100 parts of minerals that were left over from last time. So essentially now you have 200ppm in the cup/tray/in your plant. Top watering or making sure to run water through the pot can help keep these numbers down, but some plants are sensitive to even lower concentrations of these compounds and so you wouldn't even want to expose them to that. But, we do know a bone dry plant for 2 weeks is likely going to really affect the plant and possibly kill it, while being watered with high minerals may knock it back, but with rinsing through the pot when you get the pure water may keep it from dying off.

So, I would use the tap water if you HAVE to to keep it moist till you can get more. But when you can get more make sure you get some extra to prevent the situation in the future. Or at least keep something like zerowater (shown here from Amazon) https://bit.ly/2KzHJ9O which uses ion exchange to remove/heavily reduce TDS from tap water. I don't recommend this as a long term solution though because they can't filter that much water so the cost of using it tends to be higher than it has to be.

Andrew
 
Joined
Apr 29, 2018
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If I'm reading your dada right you total RDS is 140pp. That would be too high for most CP. However, Neps have been known to tolerate higher TDS than other CP. You could topwater with the tap with a good flush on them every cuple of weeks. From you coment about not being able to get out leeds me to beleev you have a hard time leeving you house. If im corect on that you may want to invest in an RO. It would make things easer for you.
The 140 ppm is the average TDS from different locations where my utility board tested the water. In my location in particular, it measured 50 ppm - 63 ppm, had a PH of 6.8, an Alkalinity of 40 ppm and a Calcium Hardness of 100 ppm.

I'm actually considering buying an RO unit for my bathroom soon. Thanks for the suggestion though. Any brands you'd recommend or have been recommended by others? :)

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adnedarn

I'm growing CPs in the Desert of Tucson, Az
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BulkReefSupply puts out quality RO systems, I have 1 of them for each greenhouse (and a RODI "water saver" system for my reef tank). This 4 stage value 75 gallon per day system is a good value (and on sale!): https://www.bulkreefsupply.com/4-stage-value-ro-di-system-bulk-reef-supply.html Later if you need to make more water, you can add on the water saver which doubles the output while at the same time using much less water to make the water! If you decide later you don't want to use the DI part of the system to get 0ppm water you can replace that stage with a 3 micron carbon block, but the RO version is the same as the RODI so you may as well get the RODI :D

The upgraded version of the same system which comes with inline pressure gauge (to show when filters are getting clogged and need replacing) and inline TDS meter to help monitor water production in real time before and after the DI stage to let you know when your DI needs replacing is worth it's money IMO. https://www.bulkreefsupply.com/4-stage-value-plus-ro-di-system-bulk-reef-supply.html
Andrew
 
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