Reverse Osmosis

[Neofolis]

I have just ordered an RO unit to produce water for the garden/greenhouse.  I was wondering, as my plants are all potted, does this mean, with sufficiently well draining medium, it will be impossible to over-water things.  My reason for thinking this is that no amount of rain ever seems to be a problem and the more I water, with filtered water, the less salts and contaminents will be in the soil.  I realise excessive watering will also remove nutrients from the soil, but, as I apply a weak soluble feed regularly, that shouldn't be an issue.

[Dave-Vero]

I can see reverse osmosis in southern California, where water from the Colorado River must be pretty mineralized (the Colorado traverses terrain with a lot of soluble geology), but Dorset?  Well water maybe?

[Neofolis]

It's not well water here.  Our mains water is so hard that the calcium deposits left by my misters were so thick that they were eventually making the leaves die and the ones that weren't dying, just looked awful with the limescale build up.  This caused me further concerns, with all my plants being in pots, that I would get considerable salt build up in the pots.

The unit I have ordered has an inline before and after TDS meter, so it will be interesting to see just how much crap is in the normal water supply.  I wouldn't be at all surprised if the TDS reading before is >1000ppm.

I am also interested to see how my potting medium fairs with improved water quality, because I have been surprised in the past at how quickly the medium degrades and, whilst I didn't suspect the water to be to responsible, I'm not convinced that it wasn't a contributory factor.

[Matt in SD]

Corey,

I've been looking into RO quite a bit as well.  Not sure how much research you did, but I hope your water is not as hard as ours.  Most of the RO units I looked at had TDS limits of ~2000 ppm which is compatible with our water.  But they "hardness" limits of ~10 grains per gallon (can't remember the mg/liter equivalent, but I'm sure you can google it).  My water was about 17 grains per gallon.  Basically if I ran an RO unit on my water the membrane would quickly get completely coated with calcium and crap out.  The only way to run RO around here is to run the water through a softener first (to exchange the insoluble Ca salts with soluble Sodium salts).  After the softener, the TDS in the water will be the same but the hardness will be basically 0, and you're good to go into your RO unit.

Anyways it took me a few months of reading and thinking about it to really become convinced that I could not run RO without a softener.  It sounds like that may be true with your water as well.

Oh, and regarding overwatering...I've always felt that for potted plants in a good mix, you can't really overwater stuff.  But then this is coming from a guy who lost about 35% of his potted palms this winter to some sort of mysterious fungus.

Matt

[RadPalms]

Corey...I have been looking into it also and I cam up with unit that I will purchase....700 GPD Tankless Merlin Reverse Osmosis Water Filter.....check it out on ebay...... Merlin

[Bilbo]

My water is probably as hard as yours Corey ; its been spending hundreds of thousands of years filtering thro chalk as you know!

It doesnt seem to make any difference to palms.

For Proteas and such I use stored rainwater of course.

Anyway on the subject of reverse osmosis maybe Carlo should be consulted as he does have some (mixed I think!) experience on this subject . . .

Regardez

Juan

[Neofolis]

Jon I have also been using rainwater as much as possible, but April was so absent of rain that I ran out of stored water quite early in the Month and I don't have sufficient space for multiple butts.  The other problem with rainwater is that it would generally have too many bits in it for my misters, although I won't be able to use the misters from stored water until I get a suitable pump.

Matt, yes the membrane will become soiled and need replacing more frequently.  The pre-filters will reduce the soiling to some extent, but things like calcium aren't removed until the RO stage.  Either way I expect to get 12-18 months life from the membrane, instead of the usual 2-3 years.  As it has an inline TDS meter and a pressure gauge, it will be fairly easy to monitor the efficiency of the system.  I have also got an automatic shut off system, so at least it won't be used any more than is necessary.

Curt, the Merlin system does look very good, but probably a little excessive for my needs and the filters and membrane are rather expensive.  My replacement filters and membranes should total less than £100pa, even allowing for more frequent replacement.

[Neofolis]

Jon, it's interesting that you mention Carlo, as his water source would certainly be prone to collecting all sorts of mineral deposits.  I still struggle to get my head around the fact that the Island's main source of water is dew.

[Howeadypsis]

How does reverse osmosis work excactly. i know about osmosis, but not the other way round!

We're lucky here cos our water iasnt that hard, but when we get deposits theyre red!

[Neofolis]

I haven't checked this, but I'm assuming it's called reverse osmosis, because normally when water percolates through a solid it collects minerals or deposits from whatever it is percolating through, but in this scenario it is percolating through a fine membrane that removes anything that is too large to pass through it.  In effect it is still osmosis, but it has the opposite effect that osmosis would normally have.

[Phil]

Matt,

In Encinitas, our TDS is about 650 from the city.  My RO unit gets it down to about 5.  My good to discard ratio is now one to one.  Membranes have lasted about one year in the past.  I'm trying to extend their life now with pretreatment with a large activated charcoal filter and time will tell if it's working.  If been told that chlorine is the main thing that shortens the life of a membrane.  

Phil

[Howeadypsis]

(Neofolis @ May 11 2007,13:39)

QUOTE

I haven't checked this, but I'm assuming it's called reverse osmosis, because normally when water percolates through a solid it collects minerals or deposits from whatever it is percolating through, but in this scenario it is percolating through a fine membrane that removes anything that is too large to pass through it.  In effect it is still osmosis, but it has the opposite effect that osmosis would normally have.

I remember a biology class at school years ago(like the last ice ago ago!) and we talked about osmosis and transpiration.  found this particularly fascianting as I already had an interest in plants from a very young age so I was hooked!

I remember being taught about semi permious membranes and how water crosses a membrane in a plant cell  if the fluid on the other side contains disolved sugars etc, the minerals draw the water in,just like a sponge. It was so long ago tho and I wish I'd paid more attention to what was going on and not flunked my exams! I would really have liked to taken it further too, gone to college etc and specialised in plant biology/physiology.

[Matt in SD]

I'll be interested to hear how long your membranes last.

I also thought the Merlin system looked like the best one.

Phil, so you just run the city water right into your RO unit?  I guess if the hardness take the membrane life from 3 years to 12-18 months I could probably live with that.  I think my TDS was also about 650, but the hardness was pretty high.  Now I'm thinking it may be worth a try...again.

Matt

[Neofolis]

Most of the systems I looked at that were specifically for plants had just a direct mains water feed to the RO membrane unit.  I decided to go for 4 stage with a 5 micron sediment filter, a carbon block filter and a GAC (coco coir) filter before the membrane.  Hopefully these will maximize the life of the membrane.  I couldn't see the point in adding a DI unit or post polishing carbon filter, because they only remove an extra 2-3% of the original TDS and remove bad tastes and odours left by the sediment and other pre-filters.  I doubt the plants care too much about taste and scent.

[RadPalms]

Corey.....post the name of the unit so I can check it out....Thanks Curt

[Neofolis]

It doesn't have a name as such, but it was ordered from RO-man, it is the same unit that they have listed as a "Six Stage RO with Inline TDS Meter and Pressure Gauge", but without the DI and Post Polishing stages.  Then I added the auto shut off system as a separate item, so it can fill a water butt then switch off.

[Walter John]

sisomso

[Bilbo]

Corey, as Carlo seems to be on his travels at the moment I shall take the liberty of answering for him.

Here goes: loadsa problemos despite what appears an "easy solution".

No doubt Carlo will correct me when he returns.

I suspect he is on an island somewhere.

That is his lecture speciality: "island palms" and he is an excellent and entertaining speaker.

Regardez all

Juan

[Phil]

Matt and Others,

When I first got my system, I didn't look for a "Chevy" or "Ford".  I hired an expert who assembled a system.  I think such tradesman just buy the parts, very similar to your hiring a plumber to plumb your kitchen.  He did an ok job, but certainly wasn't a wizard on the subject.  Then I began to learn about the system and started repairing it myself.  The first thing I found was that our system initially had two 20 inch filters before the membranes.  Both were charcoal/sediment filters.  But, when you make lots of water, these are shot in no time in terms of catching Chlorine.  Further study found that chlorine ages the membranes.  So, I installed a charcoal "sand" filter before everything (first in line with the water coming in).  This has about 30 gallons of activated charcoal in it, or an equivalent of at least 200 of the 20 inch filters.  This lasted for about a year before it went funky.  Then I changed just the charcoal in the filter.  Time will tell if the membranes last longer.

Phil

[LJG]

I too have spent many hours on this. As stated before I have about 1 acre of tropics I am slowly building out. I have purchased and will be installing a Dosatron inline with my sprinkler system. So the next improvement to create the ultimate watering system in the galaxy (for home use) is RO before it. I figured I needed 15 GPM support to do this. By my math, I needed 21,000 GPD support. A unit like that is bigger then most eastern European cars and much more expensive. End result? I think a whole house (to include sprinklers) filtration unit to clean the water a little.

[Phil]

Len,

An RO system typically makes the water, puts it into storage tanks from which it is pumped when you need it.  Our system stores about 4200 gallons of water.  It can regenerate this in about 36 hours.  If you need more water, you will need to do the following:

1.  Put in more RO membranes, perhaps 6 or 8

2.  Pump city water into the system as opposed to passive flow.

3.  Buy bigger tanks.

All this can be done.  Controls shut down flow if the tanks go dry.  You can convert to city water if the system breaks down or you go dry.  We're thinking of converting to 6 membranes but haven't yet done it.  Drop by and I'll show you our system and we can talk.

Phil

[Charles Wychgel]

(Phil @ May 11 2007,13:55)

QUOTE

 My good to discard ratio is now one to one.  

Phil

I take it this means you discard one unit (gallon/liter/bucket/whatever) for each unit produced?

Just wondered what you do with this waste...I had a small RO unit in my greenhouse just for misting and dropped the waste(maybe 500 liter/120gallon a week) in a corner of the garden; you must have a few thousand gallons ...do you just lead your waste to the sewer without problems with the municipality?

[LJG]

I will take you up on that Phil. Thanks. I have to come by and get my plants anyway. I did not have a truck to get them this weekend.

len

[Phil]

Charles,

Out here you have to put it into the drain, not out into the soil or down the gutter.  I just rechecked our system and it's fine tuned better than one to one.  I get 1 gallon now and lose about .6 gallons.  That's much better than old units from years past.

Phil

[palmarazzi]

this is really the only way to go no matter where you live because, the system removes all impurities. i've found, especially with tropical plants that most city water is to harsh from chlorine and fluorite and if you have old lead pipes that (over-time) affects things too.

since going with a RO system my plants and palms have never looked so good and considerable growth (plus better root development) is attained. you can even see a difference in the leaves, flower colors are brighter and blooms last longer.

even the brita pitchers do a good job but RO systems clarify water as well as nature.

An RO system is really a must for any serious palm collector/grower/retail situation.

Also if you put tap water in a pale and leave it outside in shade for a day, about 60-70% of the chlorine and flo will burn off.

[Bilbo]

Corey, solid chalk and limestone are perfect natural filters and besides rainwater is not a pollutant.

One solution (assuming as we are both in the South of England that you also are over this form of rock ) - why not sink a borehole?

OK the water will be a little alkaline but it will be certainly clean enough to drink and think what you will save on future water bills!

Remember that those water companies are hardly going to drop prices in the future and they are considering hosepipe and garden watering bans (except by hand) Ha.

Its perfectly legal at the moment to sink a borehole on your own land.

I am thinking of this myself but have some massive bills to come including a new top quality 100' fence.

And others.

Regardez

Juan

[Neofolis]

Jon, the main problem with the calicum in the water is the deposits it leaves on the plants, when I use misters.  The deposits are so severe that I suspect it prevents or at least reduces photosynthesis, apart from the fact that it results in very unattractive plants.

I am already lacking in garden space without digging a bore hole.  My water bills won't change as I am not on a meter.  Whilst RO does waste some water, my water usage for the garden is fairly minimal and I will re-route the waste water to the cold water storage tank in the loft, so in effect my water usage won't change greatly, if at all.  I already have the RO system now anyway, so it's a little late to consider alternatives.  I don't have anything against rainwater and will continue to use it, when it is available, but during months like this April, the rainwater supply doesn't last very long.

[Bilbo]

Im not o0n a meter either but that wont stop them either a) making meters compulsory

    or     increasing standing charges

    or    c) finding someother great money making idea.

Actually my Company (Southern Water)has Bewl Reservoir, Access, to several rivers such as the Arun and Adur and they ALSO bore down into the chalk aquifier and draw water when all else is running out.

I have spoken to one of their technical guys and he is a nice guy BUT at the end of the day they have to answer to the accountants . . . they call the shots.

Regardez and good wishes for your RO system.

Juan

[Neofolis]

As today is nice and sunny and there is no rain forecast for a while, I took the time to set the system up.  First impressions are a combination of good and bad.  Firstly the bad:  My pressure gauge is only reading 1.5Bar, about 30psi, so a pump may be in order.  As a direct result the waste water is pumping out at a great rate, while the product water is dripping.

The good points:  The TDS meter tells me that my mains water is only reading 284 ppm on average, much lower than I was expecting.  My product water is 7 ppm, which equates to about 97.5% removal, better than I would expect with the low pressure.

Optimal performance can be reached at about 65psi upwards, at which point I would get a better product/waste ratio and 98-99% TDS removal.  At my current pressure 95% removal is common, but it may be more efficient at the moment with everything being new.  I'm quite happy with 97.5% removal, but not so happy about the amount of waste, so I may invest in a booster pump.

[Phil]

Corey,

30 psi coming in is low.  Make sure your pre-filter is not clogged up before going further.  If not, the advantage of a booster pump is that you'll get purer RO water and get it faster.  Also, if you decide to add another membrance later, no problem.  You'll be an expert in no time and I am sure, a firm believer.

Phil

[Phil]

Another important thing for people who grow plants indoors, RO water will make your plants look much better.  Remember, outdoor growers are able to naturally leach their soil with rain.  Indoor growers can't do that and have to lug around distilled water (eventually) to get rid of the tip burn.  So, if you're only capability is indoor growing, a small RO unite will keep you happy.  And, your coffee will taste better.

Phil

[Neofolis]

Thanks Phil, yes, I think a pump is definitely in order.  Actually I was a little premature earlier.  Now the system has settled down, although the pressure obviously hasn't changed, I'm only getting 4.5 ppm on average in my product water, which is approaching 98.5% removal.

[Neofolis]

Oops, I had it setup totally wrongly.  I have now corrected my errors and the pressure is about 3.6Bars/56psi and my product water is varying between 1-3ppm.  I'm also getting a much more acceptable ratio now of about 1:2 product/waste.  I can't wait to see how the plants respond and now I don't need to buy a pump.

[RadPalms]

Take a picture of the system you put togather if you could.....I was told that the Merlin unit would not work for me the way I wanted to set it up......

Thanks Curt

[www.dadluvsu.com]

Ok, someone give a photo tour of their system...  I spent all weekend in my shadehouse and there is calcium deposits on everything...  Makes me sick...  Water in SoFla is just nasty...

I've installed a small RO unit nudermy sink before with the prepacked kit from the hardward store...  But I've got no idea of how to incorporate it into my shadehouse watering...  Larger storage vessel? larger filters?  

Phil, I noticed a couple people mentionig you use RO water...  Can you give a photo tour of a commercial setup?  Corey, a couple phots and an explination please?  I need the dummy proof plans...  I have a garden hose running to a manifold and timers and from there water is distrubted to the overhead irrigation system...  Obviously I would need to hook up the RO before the manifold, but how? Anyone know how to do it or where to send me so I can find the parts/info neccesary?

[www.dadluvsu.com]

So I can screw this onto the garden hose...

http://www.purelyh2o.com/product.php?productid=16145

and then hook up and nice sized RO unit...

http://www.bigbrandwater.com/hy4ve75gpdtf.html

and then a large storage vessel...  (they are pricey!)

http://www.bigbrandwater.com/ro86.html

My only problem that I can forsee (I'm laughin as I say that) is that I would have to use a reducing coupling to get the 1 1/4 male threaded outlet reduced down to 3/4 to accomidate my gardenhose mainfold...  Is the pressure of the water coming out of the storage tank equal to that of the tap?   30-40 psi?

[www.dadluvsu.com]

O crud, I read that wrong...  That is ONE (1) 1/4 inch outlet on the storage tank.... So how do I get it stepped back up to 3/4" to get it connected back up to the manifold and still have sufficient pressure to send the water to the mister heads on the overhead funny pipe?

[Neofolis]

I don't have any photos yet, but I'm due to photo all of my palms at the end of the week, so hopefully I will remember to take some of the system then.  Bare in mind, my diminutive setup will not compare to the needs of most, but the principles should still be the same.  I have mains water feeding my RO system.  The product water is output to a water butt.  The water butt feeds misting system, which is pumped by a diaphragm pump on a repeat cycle timer.  The timer is currently set to run for 5 seconds then wait two minutes.  I may tweak this a little, but the short bursts avoids excessive wetting and keeping the bursts very regular stops the humidity fluctuating too much.

My pump is rated to 160psi and can run up to 8 nozzles with a maximum flow rate of 0.8gpm (US).  My RO system can produce 100gpd (UK), so it is easy to ensure that I don't use the water faster than it is produced.  That said, the pump can run dry for several hours without damage, if a problem occurs.  My water butt stores 36 UK gallons, so there is a fair bit of leeway, although I use the stored water for watering as well.

[www.dadluvsu.com]

Thanks for the info Corey...  Didn't know what a water butt was so I did a search for water butt and this is what I found...  

http://www.waterbutts.com/Butt/index.html

You guys must be really bored over there on that island...   :laugh:  :laugh:  :laugh:

[Neofolis]

Do you prefer the term water storage tank?  The one's in the UK aren't generally shaped like an arse.