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Safe TDS Range?

MidnightSkies

animal lover, aquarium and CP enthusiast
Just got the reverse osmosis unit installed yesterday and the water after being treated reads 40 ppm. Would this be safe for all CPs? I've heard everything from under 100 to under 20. I do have quite a few undrained pots of plants also. Would this be a problem? Previously I have always used distilled water. This is also water softened with potassium, so I don't know if any amount of the potassium left over would be a danger for CPs.

I'm also curious, for those of you with reverse osmosis units, what is your TDS reading before and after treatment? Mine started at around 400 ppm and is down to 40 ppm today.
 
I actually am about to check the TDS on the RO system from my parents house (where I get all my water now).

Although...if u have lots of live sphagnum growing ...remember that you will see a increase in algae growth and sheet moss and some sphagnum will start dying. But given enough time...it should adapt and grow back. I find spahgnum to be extremely sensitive to water.
 
I'm also curious, for those of you with reverse osmosis units, what is your TDS reading before and after treatment? Mine started at around 400 ppm and is down to 40 ppm today.
Depending on the day: 190-350 >>> 4-8 ppm
 
Mine starts somewhere between 500 - 700 depending on the time of year and reduces down to 10 to 18. Anything under 50 is typically fine for most CPs. If you just installed the RO system, give it more time. It might still come down some after it's been runnig a few weeks.
 
500+ before, 1 or 0 after. Works really well.
 
Just got the reverse osmosis unit installed yesterday and the water after being treated reads 40 ppm. Would this be safe for all CPs? I've heard everything from under 100 to under 20. I do have quite a few undrained pots of plants also. Would this be a problem? Previously I have always used distilled water. This is also water softened with potassium, so I don't know if any amount of the potassium left over would be a danger for CPs.

I'm also curious, for those of you with reverse osmosis units, what is your TDS reading before and after treatment? Mine started at around 400 ppm and is down to 40 ppm today.

In the last five years, I have killed the membranes of two RO systems with the mineral-laden water out here (anywhere between 500-750 ppm); and the usual reading from the system was around 15-20 ppm. It usually goes down after a bit; but anything below 50 ppm should be fine and the live sphagnum I use for many plants have seen far worse.

Having a TDS meter on hand should be a primary concern for all of us.

Good luck . . .
 
I figured the numbers might go down a little still. It's hardly had any water run through it yet, just the filling and draining of the holding tank (~3 gallons). Based on the numbers everyone else has it looks like I'll be more safe as time goes on. Maybe I'll stick with finishing up the distilled water first and using the RO for drinking and fish tanks for a while. At least I hope the numbers go down at least since everyone else has such a big difference.

Thanks everyone. At least now I don't have to be so worried about losing anymore plants (didn't have the best winter this year)
 
I have noticed that while my tds readings are very good, a lot of calcium is still in the water. My humidifier gets coated with it after about a month. It hasn't coated anything else though. But still I thought that if that much calcium is being missed it would show up on tds readings.
 
I have noticed that while my tds readings are very good, a lot of calcium is still in the water. My humidifier gets coated with it after about a month. It hasn't coated anything else though. But still I thought that if that much calcium is being missed it would show up on tds readings.

Wha....Your RO doesn't remove it?!? ???
 
  • #10
Wha....Your RO doesn't remove it?!? ???

I'm honestly just guessing it's calcium. Whatever it is, it's making it through the RO but not registering on the TDS meter. I have 2 tds meters, and they both register my post ro water as 1 or lower. Our culinary water has insane amounts of calcium in it (our sprinklers have permanently etched the paint on our cars.)
 
  • #11
MidnightSkies, My R/O TDS is 0-1 PPM. Let it run a few gallons and if that doesn't help it may be hooked up wrong.
Don't use the R/O water for freshwater fishtanks. It causes the PH to fluctuate.
 
  • #12
The question about 'safe' TDS is a fairly regular one on the forums & the answers are usually in the same genre. However, imho - one of the most important concepts to keep in mind is the bigger picture. CP tend to do poorly where minerals become concentrated (& not all CPs have the same tolerance). Someone who keeps their CP outside in the cool rainy Pacific northwest - is less likely to have concentrated mineral salts because they have smaller evaporation losses to concentrate the salts & rain flushes the salts out on a regular basis. Otoh, a grower in the desert will likely have high evaporation & fewer cleansing rains so their salts will concentrate more quickly.

Growing practices should also be considered - for example:
- how frequently are plants repotted? Do the plants grow in the same pot for years?
- Are plants watered with the tray method (& never flushed)?
- was the original media checked for TDS and flushed? Some sands are notorious for high TDS...

What plants are being grown? Supposedly Neps are fairly tolerant of higher mineral concentrations and some Darlingtonia may be less tolerant iirc.
 
  • #13
MidnightSkies, My R/O TDS is 0-1 PPM. Let it run a few gallons and if that doesn't help it may be hooked up wrong.
Don't use the R/O water for freshwater fishtanks. It causes the PH to fluctuate.

I had drained all the water in the holding tank (3 gallons) before testing. I haven't tested yet today after using more water yesterday. Is it possible to hook it up wrong? It's basically water hooks up to one end and comes out the other.

I don't have a choice but to use RO water for my tanks. I'd like to plant them. We have so much potassium in the water that it kills plants and inverts. It's not the best for fish either, with not having much besides potassium in it. Using water from before the softener isn't an option. I am aware of adding back what needs to be in the water. I'm not just a CP enthusiast, but aquarium as well :)
 
  • #14
RL7836,
Nice overview of looking at the whole picture. It is one of the most important things to do, and yet the most common to overlook, mistakenly getting caught up into specific "rules" and "how-to's" and "answers". Only the most experienced (or wise) growers seem to understand the importance of looking at the entire eco-system that they are subjecting their plants to.

(Not in reference to this post, but...) It seems that a lot of times people don't even notice the nuances of the environment they have created, and sadly they don't understand its overwhelming effects that it has on their plants. Most people want a simple answer and don't want to be bothered with having to work to interpret what their plants are showing in response to it. Yet to me, understanding a plant's response is what makes the process of growing the most rewarding! Again, it is always nice to hear when others remind us to consider "everything" involved in the equation, and not focus on only one or two things!

Midnight...
Sounds like a difficult water situation. In N. Illinois (and elsewhere), water quality varies greatly. I am wondering, is using filtered rainwater a possibility for you in addition to R.O.? (I use rainwater for nearly everything now, but not for aquarium use necessarily.) As for my plants, it works out perfectly, and while not as convenient as going to an indoor tap (outdoor tap on my barrel!), I don't have to buy any membranes and filters and such. And again, the water quality has been great so far! In relation to your TDS readings, I agree to run it for a while before taking a reading.
And again, from what people are saying, the readings you are getting indicate the water is fine to use, and that is the most important thing.

Zero...You mentioned: "Don't use the R/O water for freshwater fish tanks. It causes the PH to fluctuate." I am curious as to why that would happen?
I haven't done nearly as much with the "real" fish hobby for a number of years (Just some common stuff now to have some life around the house) and so I am not up to date on things. I am just curious as to why the PH would fluctuate... (If the source doesn't change, and any treatment to the water is consistent, what would create variations of the minerals that are dissolving in the water source or otherwise affecting its PH?)
I know, I am probably overlooking something obvious, but this weekend has been a bit "active" and I am on about 3 hours sleep right now! But anyway, if you have a moment, tell me what you think!

Well, good luck to all with the water situation. I know rainwater is not the best sometimes (with pollution and such), however it is the closest thing to what the plants are getting in the wild, and it is free! Besides, lugging around containers of water is good exercise, and I don't need to go to some gym to get it! (The exercise, not the water!)

Paul :water:
 
  • #15
I do try to use rainwater when possible, but I don't have a rain barrel and am a little nervous to get water off of the roof honestly. I do put containers out in the open to collect rainwater, but with living in a rural area, there's nothing to block the wind. When we get the heaviest rains even the plants have to be brought in sadly. I've learned my lesson with a few too many uprooted plants and knocked over pots. I do get quite a bit of evaporation also, so rainwater just isn't able to keep up without a barrel to collect it. When I have it I do use it though.

TDS is reading 19-20 today, so it does look like it's still dropping. With the reading today I'm feeling much better about using it on the plants. I was a little iffy on 40 in undrained containers.
 
  • #16
RL7836,



Zero...You mentioned: "Don't use the R/O water for freshwater fish tanks. It causes the PH to fluctuate." I am curious as to why that would happen?
I haven't done nearly as much with the "real" fish hobby for a number of years (Just some common stuff now to have some life around the house) and so I am not up to date on things. I am just curious as to why the PH would fluctuate... (If the source doesn't change, and any treatment to the water is consistent, what would create variations of the minerals that are dissolving in the water source or otherwise affecting its PH?)
I know, I am probably overlooking something obvious, but this weekend has been a bit "active" and I am on about 3 hours sleep right now! But anyway, if you have a moment, tell me what you think!



Paul :water:

Stuff that leaches out of organic materials lower ph, stuff leaching out of minerals usually increase ph.
Increased co2 in water lowers ph.
Co2 in water is fluctuates a lot during the day.
If you got enough calcium i think in your aquarium water it acts as a buffer (don't ask me how it exactly works) and gets used up by the increased acidity, keeping your ph level.
As long as you got that stuff in your water ph won't drop afaik.
So pure ro water has no buffer and is highly unstable.
 
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