Safe water for orchids.

[cheekma]

I am new to the orchid board and have a question for the more experienced members. We built a sunroom and connected the outside faucet to the sunroom for water. Unfortunately, the original plumbing in the house was messed up and the water softener affects all faucets, including the outside faucets. Although I understand that rainwater would be best for the orchids, it is just not practical. We have well water and I am currently going into my basement and filling the water from a single faucet that is before the water softener. Is there a filter that I can use beneath my sink that will filter the salts from the water softener so that I can use the water in the sunroom? Can I use any of the filters that you see in the hardware stores that "purify" the water for drinking? Or is there a specific filter that would be good for using for orchids? Thanks so much.

[RosieC]

Welcome to Orchid Board.

As I understand it a filter for drinking water will not remove the salts. What happens with a purifier is that it replaces Calcium Salts with Sodium Salts, this makes the water softer but the Sodium is not good for plants. Filters only filter and don't help remove salts, or at least only minimally do.

You might be able to use a RO system (Reverse Osmosis). I don't know if that removes Sodium Salts or not but I think it might. Ray on this forum is most likely to know for sure on that. He has a vast knowledge of these types of things and also sells RO systems in the USA because he found them so good for his own orchid growing.

P.S. I've moved your post to the beginners forum as the "About this Board" area is really just for information about the forum rather than questions about orchids. This way more people should see it

[cheekma]

Rosie, thanks for the tip on reverse osmosis. I will check it out. Hopefully Ray will comment. And thanks for moving the post - I just recognized my mistake and was trying to correct it. Mike

[JanS]

I just returned from Chicago where I could not resist a visit to the huge Houserman's Orchids greenhouses and buy a few plants. I've been worried about watering my orchids here in Southern California since we have very hard water (and no rain for most of the year to collect). I noticed Houserman's uses an RO system and asked them about it since I also worried that the chloride salts ROs inject back into the water could hurt the plants (RO systems take out various minerals and compounds but replace them with NaCl salt).

The Houserman story is that they use well water, but its mineral content got really bad over the years and hurt their plants. About 8 years ago they installed the RO system and noticed an immediate improvement. Apparently, the plants don't mind the NaCl salts. So short of collecting rain water, RO is the way to go and that's what I am going to install in our house. As Rosie says, in-line filters do not take out dissolved minerals.

[RosieC]

I could be wrong on this but I didn't think that RO replaces the salts with NaCl salt. That's what water purifiers do and the advice is not to use those.

My understanding is that RO forces the water through a membrane that does not allow anything other than the water molecules to pass through. The Calcium salts being bigger molecules than water molecules.

I could have that completely wrong but I thought that's why we advice RO while NOT advising purifiers

[JanS]

I think Rosie is right - an RO system should just osmotically hold back the impurities whose molecules are bigger than H2O. What confused me is that at Housermans there were bags of NaCl salt lying on the ground by their giant RO setup. Are they putting some salt back into the water??? Why would they do that? I'll give them a call to find out - whatever they're doing sure works great judging from the looks of their plants...

[samarak]

Rosie is right - RO units don't replace the stuff they "remove" from the water with anything. They just don't let it through and it goes out in the waste water stream. There are "water softeners" that use salt (NaCl) to replace calcium and magnesium ions, but sodium is usually not good for plants and I would never want to use water from a salt-based water softener on any plant.

Rosie is also right that most drinking water filters will not remove dissolved salts (I've tested several) but there is one that will: ZeroWater. When my wife saw the ad for this we didn't believe the claim, but we bought one and tested it (with our own more expensive TDS meter, not the one that comes with the ZeroWater) and they do what they claim. We use an RO unit in the greenhouse, but I've become a big fan of ZeroWater for situations where people just want a few gallons a week of high-quality water. It works out to being a lot cheaper than buying distilled water and a lot less work than lugging it around. I keep one at my office for the plants on the windowsill.

Sorry for the long post - since my wife and I both have strong chemistry backgrounds, I get into water quality.

[JanS]

Originally Posted by samarak

Rosie is also right that most drinking water filters will not remove dissolved salts (I've tested several) but there is one that will: ZeroWater. ZeroWat

I just looked this product up and it's @$50 - not bad as a temporary solution before we get our permanent RO system! How long do the filters last and how much are they? Thanks!

[samarak]

Hi Jan - there are several models of ZeroWater, the one I use at my office was about $35 at Target and included one filter and a "free" TDS meter. (The TDS meter is not an expensive model but I've tested it against my other units and it's plenty accurate enough for most things, and after I calibrated it it's really pretty decent.)

You asked about the filters - they cost about $15. How long they last depends on how good your water is to start with (i.e., the less stuff to take out, the longer they'll last). Our tap water runs from about 85 to 100 TDS (as measured in ppm NaCl, for the techies) and I get about 60 gallons per filter, so about $0.25/gallon. When the output from the filter reaches 6 ppm TDS they recommend you replace it, and my simple experiment says they know what they're talking about because when it hits that point the filter is exhausted and the numbers will go up quickly. They did have a program where if you mailed the used filter back to them for recycling they'd send you a $5 coupon to pay for the shipping, but I haven't looked to see if it's still in effect.

[Rowangreen]

Re RO systems: I read somewhere that most systems just take stuff out. But there are some more 'fancy' systems then add back some stuff that's supposed to be good for humans. So you want to make sure you get a system without that stage.