Depends on if you're using well water or city water. High PPMs in water aren't always problematic, one can usually adjust their soil recipe/inputs to compensate for high mineral content in their water source.
Its only if those high PPMs come from Calcium Carbonate specifically, because this will in fact mess with your soil. Using water with Calcium Carbonate in it is essentially the same as dissolving Dolomite Lime into your water before using it. Over time, your soil pH will get alkaline as a result of this water and you'll have a bad time. Trust me lol.
I just looked at your city water, here's the
link for your review. Looks like our water is pretty similar to each other's.
What we want to look for is "Hardness (as CaCO3), mg/L", as this tells us whether the Calcium in the water is in Carbonate form or not. If one's water report shows Calcium, but nothing about "hardness as CaCO3 (Calcium Carbonate)", then your water isn't likely to buffer pH. You can always call your water district and ask if in doubt.
Check the footnotes on the side to find out what specific region of your city is what ID No. Range on the report I linked.
"(2) Cove Communities includes the communities of Rancho Mirage, Thousand Palms, Palm
Desert, Indian Wells, La Quinta, Mecca, Bombay Beach, North Shore, Hot Mineral Spa; and
portions of Bermuda Dunes, Cathedral City, Indio, Oasis, Riverside County, Thermal, and
Valerie Jean.
(3) ID No. 8 includes the communities of Indio Hills, Sky Valley; and select areas within and
adjacent to Desert Hot Springs.
(4) ID No. 11 includes the communities of Desert Shores, Salton Sea Beach and Salton City."
Regardless of your region, it does in fact appear that your water has Calcium Carbonate in it, based on the report at least. Now all that's left to do is confirm it by pH test. You've already tested it at 8.2, however have you checked to see if the water buffers or not?
Make another pH sample, wait for the water to turn dark green for 8.0+ pH. Then, dump enough vinegar or lemon juice into the solution until it is a 4.0 or lower pH. Wait 24-48 hours, and observe the solution over time.
If the water goes back to 8.0, that means your water is a buffer.
Not sure how much help your carbon filter is with the carbonate, but it must be working well if you've not had any problems using this filtered water in the past.
If your water is in fact capable of buffering your pH, you do have options on how to deal with it, or you can work with it.
1) Your carbon filter may be working, only a pH test would confirm if the filter removes enough carbonate from the water to remove it's buffering capabilities. If this is doing the job, and isn't too much of a pain/you're only growing a few plants, this can work. Sounds like it has already.
2) RO, as you've mentioned. Pricey, and pretty wasteful, but it does work. A little too well, in fact, you may have to add certain amendments to compensate for the good minerals being stripped by the RO.
3) Bottled water/water machines. Will definitely work, but same as #2, be sure to compensate for the minerals stripped from the water, and by proxy your soil.
I've found the best solution is to work
with it, and use it to our advantage. If our water is a buffer, then all we need to do is remove Oyster Shell Flour/Dolomite Lime from our soil mixes and we can use the water just fine! The water does the job of the Lime, buffering the pH for you.
Test this and see it for yourself.
Do the same pH test as above, but soak your tap water in pure peat moss (nothing else) for an hour or so, then pH the peat moss water. Peat moss has a very acidic pH, 3.5-4.0, if you test it with distilled water. However, since you soaked the peat moss in your water, the pH of the solution should be a perfect 6.0-7.0 range and never deviate.
My solution was to just stop liming my peat moss, opting instead to let my water lime the soil for me. I also made sure to remove gypsum, crab meal, and other Ca inputs from the soil. Saw improvements immediately.
And a bit of a tip for if you decide to venture outdoors with your grow. Do not use pots, plant in the ground, and you'll never see this issue.
Your native dirt should be like mine, sandy and clay. Amazing drainage. So amazing, that daily watering will ensure your Carbonate water will never effect your roots because it will always get pushed down into the Earth with each watering. Using pots is where this type of water is super problematic because the Calcium Carbonate can't be pushed out of the pots with watering like it can in the ground.
Hope the above was useful to you. All the best.
