PlanetCatfish.com

Hi All,

As our water supply has become more unpredictable in terms of pH, phosphate and nitrate content I am going to take the plunge and go down the route of getting a reverse osmosis unit.

I am looking at a 50 or 100 gpd maximum unit. Reading around the subject there are many many units available from 4 stage to 6 stage, with or without pressure gauge, flush kit etc etc.

I was just looking for recommendations of units in the UK, which manufacturors have shown to be reliable, or sellers with good after sale service.

Also, I have read that often reverse osmosis water can then be mixed in part with tap water to ensure it has some minerals in etc, but solutions can also be bought to remineralise the water.

Does anyone use one specific method? I guess it would be possible to use tap water if the contaminants are relatively low in concentration?

Your thoughts, recommendations and advise are much appreciated

Cheers
Stuey

I have this one:
http://www.osmotics.co.uk/products/3-St ... ystem.html

(It is my fourth RO unit - I "lost" one when my (now ex-)wife decided to donate my fish, tanks and equipment to someone who needed more than her [note: not more than me!], and I had to get a new unit when I moved, as I needed to keep the old one in place when moving the 11 aquaria, as I couldn't move all tanks in one day, and needed to make water changes at both "old" and "new" place).

I haven't needed to use their after-sales service, but their delivery and products seem to be just as good or better than the others I've got/had.

Four or six stage units are pretty pointless for freshwater fish. If you have a reef-tank that need 0ppm rather than the 10-15ppm that you get out of this sort of unit, then you need a 4-stage with DI to remove that last few ppm.

The flush kit is a tap that allows you to run water with no back-pressure through the system (bypassing the "back-pressure device" (technical term "flow restrictor") that is what makes the whole system actually work - it is what builds the pressure for the RO membrane to "push" the little holes that "sieves out the stuff you don't want"). It is supposed to allow the membrane to clean off, and you do that once in a while. I'm not entirely sure how well it works, but I'm sure it doesn't cost many pence extra to have the valve on the unit for good measure. Pressure gauge will tell you what pressure you actually get to the unit.

Two more things I would recommend:
* A tap-connector that fits onto a regular outside tape or a "washing machine tap":
http://www.osmotics.co.uk/products/Tap- ... -Tube.html
Much better way to fit it than a "vampire clamp" (little spike that punctures the copper pipe - they lose quite a bit of pressure)

* Auto shut-off valve kit:
http://www.osmotics.co.uk/products/Auto ... Valve.html

This shuts off when your water container is full. Very handy, saves having to either waste water down the drain or having to mop it off the floor when your container overflows.


I'm kinda lazy, so I mix TMC Re-Mineral Tropic into the water (directly into the tank together with the new water - that is NOT the recommended method, but I haven't had any problem with it - your mileage may vary) - not just being lazy, but because to mix tap-water back in would mean storing some tap water as well as the 400-500 liter of RO water that I currently have space for, and mixing the two together before adding to the final tank.

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Mats

The one Mats linked to looks ideal. A few things to bear in mind though:

1) Water pressure is really important. It's good that they are honest about this on that advert. Low water pressure really does reduce the output.

2) RO filters waste a lot of water, so it's not even worth thinking about them if you're on a water meter. Even if you're not on a water meter, it's good to try to store and use the waste water somehow. Watering plants, garden, pond, toilets, showers, car, etc etc. It's actually perfectly good to use on non-softwater fish, as it has been dechlorinated by the carbon filter, and doesn't seem to have a higher TDS that the tap water.

3) You'll need to buy a conductivity meter, so you know that it's working, and when the membrane needs replacing.

4) The first few hundred litres of water that comes out will have a very high pH. I think this is the preservatives that the membrane is stored in. Best give it a long run before use.

racoll wrote:2) RO filters waste a lot of water, so it's not even worth thinking about them if you're on a water meter. Even if you're not on a water meter, it's good to try to store and use the waste water somehow. Watering plants, garden, pond, toilets, showers, car, etc etc. It's actually perfectly good to use on non-softwater fish, as it has been dechlorinated by the carbon filter, and doesn't seem to have a higher TDS that the tap water.

This is obviously one of those rather relative things. It depends on how much RO water you use (the unit will produce approximately 3-4 times the waste vs. purified water), so for 1 cubic meter of pure water, it's a total of up to 5 cubic meter of water from the meter. That's about £15 with current water rates. If that lasts a week, then it may become an issue. If it lassts 3 months, then it's £5 a month, which is probably in the noise when it comes to household finances... A lot of people end up somewhere between those two...

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Mats

Thanks for your input guys, much appreciated.

Water meter won't be an issue (at least not for the forseeable)as property still on flat water rates with no meter.

I was more interested in type of unit to buy, etc, which you have given me some great comments on

Cheers
Stuey

Hi Stuey

I use a D-D RO unit 50 GPD, I need about 200L + per week its a great unit 1ppm -7ppm you can't ask for better than that.
It has, durining the winter months only made 15L-16L RO from 2100- 0900, when the weathers warmer I get 25L 2100-0900, this is also due to my low water pressure and me not fitting a Booster pump.
I fit my unit onto the kitchen tap, using a hose pipe connection, drives the wife mad !, but if it wasn't that winding her up she would be banging on about something else anyway.