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FAO Spruce or Anyone Else Who Knows About RO

Tuffers

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@spruce, I'm going to be moving into my new house in the next couple of weeks. I'm moving from a soft water area to a hard water area. The PPM in the new area is just over 200. I'm thinking of getting one of these and house it in my garage http://www.purefreedom.co.uk/water-purification/reverse-osmosis/2400-gpd-high-volume-ro-system-c-w-auto-shut-off-1000ltr-tank.html.

I've done a water pressure test today and this is the reading View attachment 8423

I know nowt about RO, but would I need a HF4 or HF5 filter?

 
My water pressure is just fractionally higher at 50psi. I got an HF5 membrane and have been pleased with the results over the last 4 years. I do not have a booster pump.

I would also do a flow test to give youself an idea of how much water you are getting at the tap. It doesn't have to be exact, just a short piece of hose filling a 25 liter plastic container for 1 minute. You can have pressure at the gauge but if the water only trickles out of the tap then you may have a problem 'feeding the beast.'

Our tap produces about 13 liters per minute. Set at a 1 to 1 ratio waste to pure the r/o will consume about 4 to 5 liters of water per minute. At 50psi we get approx 2 liters of pure to 2 liters of waste per minute with a rejection rate of slightly higher than 98%. (Our tap water is between 90 and 120 ppm and I've never seen the r/o pure higher than 2ppm once it settles down.)

Gardiners have some info on their site regarding what the manufacturers of the membrane they supply should work at.

HF4 = Optimum input water pressure range 80-105psi

HF5 = Optimum input water Pressure range 50-100PSI

If you do need to go the booster pump route then you need to watch pressures as an HF4 would probably be more suited to boosted setup if you went for a Clarke 240E (max pressure 112psi.)

Gardiners now do a booster pump suitable for a 4040 giving a maximum boost of 85psi. This is within the working range of an HF5 membrane. Logically for me I would try an HF5. If the results aren't good and you need a booster, then using the Gardiner unit will mean you can still use the HF5 membrane.

HF5 membranes do cost a little more.

I wouldn't say I'm an r/o expert, its just my experience with my 4040. /emoticons/smile.png

I was also at a loss as to which membrane to buy when I went the 4040 route 4 years ago. PF told me that I wouldn't notice any performance difference between the 2 membrane types at our then water pressure of 40psi. Contrary to advise, I went with my gut feeling and opted for the HF5 membrane. I have no regrets with that decision.

If you are looking for experts then Alex and Doug have forgotten what I still have to learn.

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As always top info from @spruce. I can't do a flow test as I won't be at the house until I move in now. I'll probably give PF a ring and get their advice to whether to buy a booster pump too. I'll be asking loads more questions in the next few weeks.

 
As always top info from @spruce. I can't do a flow test as I won't be at the house until I move in now. I'll probably give PF a ring and get their advice to whether to buy a booster pump too. I'll be asking loads more questions in the next few weeks.
I would buy a unit with an HF5 membrane and see how it performs.

If it does work well then you have the option to fit a booster pump.

If my memory serves me the booster pump that PF sell has the facility of adjusting the boost pressure to optimum by means of a by pass valve. So this would be a question to ask.

Another is how they switch on and switch off the booster pump. A float switch in the IBC tank operates a solenoid valve which opens and closes the water flow to the r/o, but I would imagine that some form of relay would be required to control the motor due to the current (amps) it would draw.

The booster the Gardiner sell is electronically controlled and appears to operate on pressure in the water line. That would then determine that the booster pump is situated after the solenoid valve. So IMO the Gardiner one would be easier and more cost effective to fit.

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