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Hi everyone just wondered if anyone has any info on reverse osmosis makers with regards to which one, price etc as there seems to be so many to choose from and all claiming excellent results 

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Hi,  It might be worth checking out a few marine fish keeping forums as a lot of people use RO water for reef tanks once they realize that the water that comes out of the tap can have higher nitrate levels than the water they are changing. I do know that they use a vast amount of water just to produce a small amount of the pure stuff.  I used to buy a small quantity from a local aquarium shop and store it for doing floating Drosera binata leaf cuttings. If you only need small quantity for emergencies (otherwise known as heatwaves) and or have metered water then buying might be an option to consider.

 

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Hi thanks for that,in the heatwave I'm using about 50gallons every three days or so and we are not metered here 

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Don't worry too much about brand names or hype, and try and look at the key features/components and decide what you want. Lots of research is helpful.

You'll see GPD quoted against them; this stands for Gallons Per Day and is a measure of how many (US) gallons of pure RO water the unit can theoretically output in 24 hours of operation. This is an optimum figure though, dependant on having perfect flow pressure, clean and clear membrane and filters, short pipe runs etc., so expect a real world output lower than this.

The next important thing to think about and you'll see quoted is the "number of stages" of a unit...

The simplest is a three stage unit - which consist of a sediment filter, activated carbon filter, and the RO membrane itself. The sediment filter removes fine particles, dirt, sand etc from the water. The carbon filter removes almost all of the chlorine and other chemicals from the supply. The RO membrane then does most of the work to remove the dissolved minerals in the supply.

The output from a 3-stage unit is almost pure and removes about 90-99% of contaminants. Depending on the properties of the incoming water supply, this may be perfectly fine for CPs as even a 90% reduction on very hard water of approx 400ppm TDS, will yield 40ppm TDS output.

If you want pure water, i.e. 0ppm TDS, you will need an additional DI stage after the RO membrane. The De-Ionasation resin removes the last 1-10% of contaminants.

Some call this a 4-stage RO unit, some call it a 3-stage with DI resin, some call it a 4-stage with DI (I.e. inclusive)!... This is where some confusion can occur and you should always look and work out what the stages are doing.

You can find some 5, 6 or even 7 stage units but in my opinion these are not necessary for our plants and you'll be just throwing money away.

Pre filters will need replacing approx 6 months-year or more depending on use and the RO membrane itself should last longer at a few years+, again depending on use. If you test the output water and notice a climb in TDS, this means the membrane needs replacing. DI resin usually changes colour when it is depleted so you can easily see when it needs changing.

As you are not metered, you can easily run it for long periods and not worry about cost! The waste water can be plumbed straight into a drain and just run the unit until the required water butt/container is full of pure water.

That is the basics of an RO system. You can add extra bits to suit your needs, such as flush valves, shut off ball valves, pressure gauges, auto shutoff valves etc.

Hope that helps somewhat, and hasn't confused you further!

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gundog.

I bought the TMC V2 Pure Advanced unit about two months ago from the local Maidenhead Aquatics had it for a good price, and I think it is good value.

Like yourself I am not on the meter, I now have 600 litres stored and just top up the tanks as i use it, I get a TDS reading of between 1-3 depending on the quality of water going through it each day, its surprising how the quality changes by the hour.  It has an inbuilt TDS meter which shows the quality of water coming in and going out, and also a flush valve. Like Stu said it does not make the amount of RO water as stated in the literature. I have it installed in my shed and have put a long length of waste pipe on it and I just move the pipe around the garden and leave it to water the plants.

I purchased mine as I had a bacteria problem in my water butts and considering I was stocking 2200 Litres  in butts I did not know which one was the problem, so now I do not have to worry, I use around 80/100 litres every couple of days or on hot days I can use that a day.

I also grow a lot of Disa orchids with the Carnivorous plants hence why so much water is used.

Hope this helps.

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Hi gundog,

I can collect a bit of rainwater round the back of my block of flats, but because this is limited I too recently bought an RO unit. I got it from http://www.osmotics.co.uk/ .

Got the whole set up including a pump for a bit under £250. I needed a pump because the ambient water pressure here is not enough.

I plumbed it into the cold tap under my sink, which after a little bit of twiddling made a perfect seal. I'm very pleased with the quality of all the equipment, but I have to admit, I have just trusted the outflow, I have not tested it. I try to save the waste water for watering less fussy plants, and use citric acid to correct its pH. I'll get back here when I finally get around to testing it.

Karsty.

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On 26/06/2017 at 1:34 PM, Ron said:

gundog.

I bought the TMC V2 Pure Advanced unit about two months ago from the local Maidenhead Aquatics had it for a good price, and I think it is good value.

Like yourself I am not on the meter, I now have 600 litres stored and just top up the tanks as i use it, I get a TDS reading of between 1-3 depending on the quality of water going through it each day, its surprising how the quality changes by the hour.  It has an inbuilt TDS meter which shows the quality of water coming in and going out, and also a flush valve. Like Stu said it does not make the amount of RO water as stated in the literature. I have it installed in my shed and have put a long length of waste pipe on it and I just move the pipe around the garden and leave it to water the plants.

I purchased mine as I had a bacteria problem in my water butts and considering I was stocking 2200 Litres  in butts I did not know which one was the problem, so now I do not have to worry, I use around 80/100 litres every couple of days or on hot days I can use that a day.

I also grow a lot of Disa orchids with the Carnivorous plants hence why so much water is used.

Hope this helps.

How did you know you had a bacteria problem

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