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UK Window Cleaning Forum => Window Cleaning Forum => Topic started by: ftp on May 05, 2009, 07:52:52 pm

Title: When membranes go ......
Post by: ftp on May 05, 2009, 07:52:52 pm
Does the tds start to rise when the membranes get to the end of their life?
My 300gpd used to produce water at 6ppm it's now at 20ppm and that's after a filter change too.
Title: Re: When membranes go ......
Post by: kevin James on May 05, 2009, 10:36:01 pm
Hi Dave,
thats what happened to mine. Blocked filters slow down the water flow & lower the pressure in, dodge membrane sends the tds up.

Kevin
Title: Re: When membranes go ......
Post by: leapstallbuildings on May 05, 2009, 10:36:31 pm
Does the tds start to rise when the membranes get to the end of their life?
My 300gpd used to produce water at 6ppm it's now at 20ppm and that's after a filter change too.

The usual symptoms are a rapid rise in TDS and a rapid fall in production.  If it's a TDS rise as you describe and no other problems, could it be that there is a drop in water pressure as that can cause TDS to rise as well?  Might be best to hold fire for the momentr re changing membranes until it becomes clearer.
Title: Re: When membranes go ......
Post by: ftp on May 05, 2009, 10:41:21 pm
They are two years old now, I use a booster pump. The tds was rising and the filters were due their six monthly change last week. I changed them and expected the tds to gradually fall but it's going the other way all the time.  :(
Title: Re: When membranes go ......
Post by: d s windowcleaning on May 05, 2009, 10:50:41 pm
They are two years old now, I use a booster pump. The tds was rising and the filters were due their six monthly change last week. I changed them and expected the tds to gradually fall but it's going the other way all the time.  :(
where have you learnt that your filters need to be changed 6 monthly ?
Title: Re: When membranes go ......
Post by: geefree on May 05, 2009, 11:09:06 pm
i use around 600 litres per day... changed filters on 300 gpd ro.... twice..... in 2 and a half years.

have you flushed the membranes? for 20 minutes.

have you changed the time of day in which you fill your tank?

water pressure is very low during the day and early evening, with high usage,

mine drops when the dishwasher and washing machine are on.!

obviously we all do it in the dead of night, but i was curious.
Title: Re: When membranes go ......
Post by: chris@c.m.s on May 05, 2009, 11:11:05 pm
I have a pumped 4040 and my tds has risen recently as well from 6-12, I have new filters on order that will hopefully be here by the end of the week, so I'll let you know what happens with mine when I change them.  
Title: Re: When membranes go ......
Post by: ftp on May 05, 2009, 11:29:31 pm
They are two years old now, I use a booster pump. The tds was rising and the filters were due their six monthly change last week. I changed them and expected the tds to gradually fall but it's going the other way all the time.  :(
where have you learnt that your filters need to be changed 6 monthly ?

My filter housings have stickers on them saying filters must be changed every six months max.
Title: Re: When membranes go ......
Post by: d s windowcleaning on May 05, 2009, 11:35:15 pm
They are two years old now, I use a booster pump. The tds was rising and the filters were due their six monthly change last week. I changed them and expected the tds to gradually fall but it's going the other way all the time.  :(
where have you learnt that your filters need to be changed 6 monthly ?

My filter housings have stickers on them saying filters must be changed every six months max.
it should allso say a amount of water and to change at whichever comes first .
Title: Re: When membranes go ......
Post by: ftp on May 06, 2009, 08:08:10 am
It says MAX LIFE SIX MONTHS so that's what I stick to.
Title: Re: When membranes go ......
Post by: ftp on May 08, 2009, 08:36:07 pm
Fitted new membranes this afternoon and tds is back down to 6ppm  :)

Cut one of the old ones open to have a look at how it's constructed. Nothing much to look at, i'm surprised they are so expensive to be honest.
Title: Re: When membranes go ......
Post by: chris@c.m.s on May 08, 2009, 10:59:04 pm
Hmm I fitted the new filters to mine and tds came down from 13 to 9 maybe my membrane is starting to go but I'll hold on a while longer.