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Smurf
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Indeed /emoticons/biggrin.png
Well All, I've picked up my Van and system /emoticons/smile.png and I'm really happy with it, the tank was completely empty except for roughly 20-30 ltrs of water. It took around 14 hours to fill completely 
and gives me a TDS reading of 9 at the mo. I've been in touch with PF and they have confirmed it is a 450gpd unit and a 400ltr tank. Now the chap I brought it form was open and honest and admited that the didn't really maintain the ro unit very well ie regular flushes, filter changes and di changes :thumbsdown:. So now I need to get the water running pure, am I right in presuming that if I order and change all the filters and membranes and put in new DI resin that this should be a good start in reducing the TDS reading? Cheers All :thumbsup:
and gives me a TDS reading of 9 at the mo. I've been in touch with PF and they have confirmed it is a 450gpd unit and a 400ltr tank. Now the chap I brought it form was open and honest and admited that the didn't really maintain the ro unit very well ie regular flushes, filter changes and di changes :thumbsdown:. So now I need to get the water running pure, am I right in presuming that if I order and change all the filters and membranes and put in new DI resin that this should be a good start in reducing the TDS reading? Cheers All :thumbsup:When you buy a second hand r/o unit, either on its own or as part of a system as you have, you should expect that you have to replace the prefilters and the membranes. (450 GPD = 3 x 150GPD membranes.) If you have to replace membranes a good idea is to mark each pipe membrane housing with a pipe number, ie 1 to 9, with masking tap and then wrap a piece of masking tape around each pipe you remove and write the number on it. You will then be able to put it back exactly the way you took it apart.
To start with, some r/o use the first filter as a sediment filter, the second (middle one) as a carbon block filter, and the third one is a small DI vessel. Others use a seperate di Vessel and use the first filter as a sediment filter, the the following 2 as carbon filters.
Once you are up and running you need to identify how well your membranes are working. After the unit has been filtering for around 5 - 10 minutes you need to measure the tds of the pure water leaving the membranes but before the Di Vessel. Ideally your membranes should be removing around 97 - 99% of your tap water's total disolved solids.
Example. If your tap water is 250ppm then you would expect the membranes to reduce that to between 3 and 8. Once your membranes efficiency drops to around 94% (tds of 15) then you resins cost are going to increase alot. (For me 96% is the replacement level and our tap tds is 125.)
Maths; 250 x 97% = 242.5. 250 - 242.5 = 7.5.
In the early days our 450GPD would bring our tap water down from 254 to 4.
To start with, some r/o use the first filter as a sediment filter, the second (middle one) as a carbon block filter, and the third one is a small DI vessel. Others use a seperate di Vessel and use the first filter as a sediment filter, the the following 2 as carbon filters.
Once you are up and running you need to identify how well your membranes are working. After the unit has been filtering for around 5 - 10 minutes you need to measure the tds of the pure water leaving the membranes but before the Di Vessel. Ideally your membranes should be removing around 97 - 99% of your tap water's total disolved solids.
Example. If your tap water is 250ppm then you would expect the membranes to reduce that to between 3 and 8. Once your membranes efficiency drops to around 94% (tds of 15) then you resins cost are going to increase alot. (For me 96% is the replacement level and our tap tds is 125.)
Maths; 250 x 97% = 242.5. 250 - 242.5 = 7.5.
In the early days our 450GPD would bring our tap water down from 254 to 4.
