Loads of answers below, in no particular order....
RO generation wastes water, the 4:1 your quote is only really when you have high inlet pressure and a clean system. With colder water and lower pressure the efficiency will be much much less, 10:1 may be typical.
So if you are using well water:-
- You will need extensive pre-filtering to get the water as clean as possible before going to the RO unit. Any decent RO supplier will be able to advise you and pre-filter requirements, usually some form of activated carbon pre-filter.
- A pressure boosting pump is a must. Generally these boost the incoming water pressure to say 8 bar so that the RO membrane operates more efficiently at 4:1 or even 3:1.
- Some units have water pre-heaters that warm the water to say 15-20'C so again the RO unit works more efficiently (but quite rare).
- You will require some way of flushing the membrane every so often, you can get controllers to do this.
- You will need some place to store the RO water, as RO water generation is actually quite slow. So you prepare sufficient RO water in a tank before use. Float valves in storage tank, auto shutoff valves, pressure regulators, flow restrictors, flushing valves will all be needed.
- You will need to consider what to do with the large volumes of waste water. If on connected sewerage, down the drain maybe fine, but if on septic tank may not be possible due to large volume of water being generated. Watering your garden or a ground soak away are other options.
- Consider a DI (de-ioniser) unit on RO output to remove all ions.
- Make sure all pre-filters, membranes and DI units are always in tip top condition. If any are "exhausted" the RO water will be contaminated (measure its TDS value) and the RO membrane quickly ruined.
You can get commercial remineralisers or you can make your own
http://www.theplantedtank.co.uk/RO.htm
or you can just mix 50% tap/well water with 50% RO water to get harder water. A good point to aim for is say 8dKH as that provides a level of buffering against pH issues and measuring equipment like pH meters will get reliable readings.
You should always test your RO water before use incase there is an issue with the RO unit, normally TDS will be fine, but if using chlorinated tap water, checking for chlorine (and/ammonia in chloramine in tap water) is all that is necessary.
You must not ever ever ever use neat RO water in a fish tank, instant death to plants and fish will be the likely result.
Technically the pH of RO water is 7, neutral, but in practice will not be, as the slightest contamination include CO2 in the air and as RO water has no buffering capacity will cause pH changes. So pH of RO water can't really be measured, and is irrelevant for fish keeping.
I would not put the RO system outside as it will be damaged by freezing. Having it inside will protect it from frost, make access to it easier, have all the flush valves, booster pumps and controllers with all associated electrics indoors as well. My mate had an RO unit for his marine tank, he kept it under the plinth of his kitchen units with a storage butt outside. He had a 50W aquarium heater in the water butt to stop it freezing in the winter. Did have problems with the feed pipes freezing though.
The connecting pipes for RO systems are generally 4mm inside 6mm outside (will be different in US of A in Olde English units) but basically small and can be run quite a long distance to storage containers. I have seen people have RO units in their kitchen and run outlet pipes under the floor to storage butts in their garage with no issue.
But then again just use tap (or well water) job done.
RO generation wastes water, the 4:1 your quote is only really when you have high inlet pressure and a clean system. With colder water and lower pressure the efficiency will be much much less, 10:1 may be typical.
So if you are using well water:-
- You will need extensive pre-filtering to get the water as clean as possible before going to the RO unit. Any decent RO supplier will be able to advise you and pre-filter requirements, usually some form of activated carbon pre-filter.
- A pressure boosting pump is a must. Generally these boost the incoming water pressure to say 8 bar so that the RO membrane operates more efficiently at 4:1 or even 3:1.
- Some units have water pre-heaters that warm the water to say 15-20'C so again the RO unit works more efficiently (but quite rare).
- You will require some way of flushing the membrane every so often, you can get controllers to do this.
- You will need some place to store the RO water, as RO water generation is actually quite slow. So you prepare sufficient RO water in a tank before use. Float valves in storage tank, auto shutoff valves, pressure regulators, flow restrictors, flushing valves will all be needed.
- You will need to consider what to do with the large volumes of waste water. If on connected sewerage, down the drain maybe fine, but if on septic tank may not be possible due to large volume of water being generated. Watering your garden or a ground soak away are other options.
- Consider a DI (de-ioniser) unit on RO output to remove all ions.
- Make sure all pre-filters, membranes and DI units are always in tip top condition. If any are "exhausted" the RO water will be contaminated (measure its TDS value) and the RO membrane quickly ruined.
You can get commercial remineralisers or you can make your own
http://www.theplantedtank.co.uk/RO.htm
or you can just mix 50% tap/well water with 50% RO water to get harder water. A good point to aim for is say 8dKH as that provides a level of buffering against pH issues and measuring equipment like pH meters will get reliable readings.
You should always test your RO water before use incase there is an issue with the RO unit, normally TDS will be fine, but if using chlorinated tap water, checking for chlorine (and/ammonia in chloramine in tap water) is all that is necessary.
You must not ever ever ever use neat RO water in a fish tank, instant death to plants and fish will be the likely result.
Technically the pH of RO water is 7, neutral, but in practice will not be, as the slightest contamination include CO2 in the air and as RO water has no buffering capacity will cause pH changes. So pH of RO water can't really be measured, and is irrelevant for fish keeping.
I would not put the RO system outside as it will be damaged by freezing. Having it inside will protect it from frost, make access to it easier, have all the flush valves, booster pumps and controllers with all associated electrics indoors as well. My mate had an RO unit for his marine tank, he kept it under the plinth of his kitchen units with a storage butt outside. He had a 50W aquarium heater in the water butt to stop it freezing in the winter. Did have problems with the feed pipes freezing though.
The connecting pipes for RO systems are generally 4mm inside 6mm outside (will be different in US of A in Olde English units) but basically small and can be run quite a long distance to storage containers. I have seen people have RO units in their kitchen and run outlet pipes under the floor to storage butts in their garage with no issue.
But then again just use tap (or well water) job done.
