should waste Tds be much higher than tap?

[ks789]

Hiya

I know this may sound dumb, but would just like some reassurance. Now, feels great, produced my first pure out of a 40 21, brill, o tds, well chuffed etc. Now, our tap waters horrendous, 540 odd, after the Ro - 25, to be expected and 0 out the Di. I just thought id test the waste water and it was 775 or so. I presume this is normal as its the waste but just wanting some confirmation if possible, cheers all : )

 

[Dave B]

That is normal for waste as it is tapwater plus the muck it has filtered to make pure

 

[ks789]

Cheers bud, yes will try a few things. Was pretty good, garden tap was not turned on too high and got 600 litres pure in about 7.5 hours or so. seemed to be roughly 60 waste to 40 pure but I need to measure it properly with measuring jug, I did it by eye. Pressure on guage going into Ro was about 55. Amazing stuff, done first house with it yesterday and car im selling today, car came up a treat.

 

[Marko067]

60/40 waste to pure is not bad. Some are a lot worse than that.  If you can increase the pressure with a booster pump you'll speed up your output and improve you waste to pure ratio. However, your electricity bill will go up. So if you're paying for your water you may find what you save on water you spend on electric to run the pump.

 

[ks789]

yeh im happy with the waste to pure ratio as wont be a huge user. I wonder if turning the garden tap higher to increase flow would change much, I think could've opened the waste valve a bit more as pressure was increasing as did so but it seemed to be just right, fascinating stuff really.

 

[Marko067]

Turning the flow up on your garden tap won't make much, if any difference as it's pressure that's the determining factor rather than the volume on how well the RO works. But playing around with it will help you understand how it all works. It did me.

 

[dave83]

do you turn the tap on full when producing pure. i have a 40/40 membrane.

 

[spruce]

do you turn the tap on full when producing pure. i have a 40/40 membrane.

Yes.

 

[ks789]

wouldnt having the tap on full splurt too much water into the system? I managed  a bit over a litre a minute of pure with 55 % pressure. I dont know as its new to me. Maybe with more coming out the tap the pressure could increase and my pre di tds would improve from 25. Like you say, try things out and see. 

 

[Marko067]

One thing you'll discover is that volume and pressure, though related are two different things. 

   When I was experimenting with my setup and trying to boost my mains pressure into my RO, I attached a Surflo pump to my garden tap with a half inch hose.  I expected to see an increase in the volume of water coming out of the hose when I turned the pump on and was a bit confused at first when it didn't make any diffence. I initially thought that it was a waste of time.  The reason, I quickly worked out was that the pump was rated at 5.2lpm and therefore was only capable of pumping 5.2lpm.  However, when I connected a pressure gauge to the output hose I noticed that the pressure had risen to 70+psi whereas before it was only 40psi.  So even though the volume didn't increase, the pressure did. 

   So I connected it to my RO and turned the speed of the pump right down with a PWM controller till the pressure switch stopped cutting in and it worked fine as a booster pump and has done so now for several years.  It only runs for about 8hrs a day about 4 days a week and stays fairly cool as it's running so slow, but it does the job. 

   I get better waste to pure ratio, and more importantly produce water at a rate that keeps up with my use.  My 300gpd RO struggles to keep up with me on only 40psi of water pressure - in winter especially.  The higher pressure also almost halves the output TDS reading of my RO, so my little 10" DI canister last ages, and that;s even with a tap TDS of around 400 most of the time.  All interesting stuff!

 

[Iron Giant]

One thing you'll discover is that volume and pressure, though related are two different things.  When I was experimenting with my setup and trying to boost my mains pressure into my RO, I attached a Surflo pump to my garden tap with a half inch hose.  I expected to see an increase in the volume of water coming out of the hose when I turned the pump on.  Imagine my surprise when it didn't make any diffence. I initially thought that it was a waste of time.  The reason, I quickly worked out was that the pump was a 5.2lpm and therefore was only capable of pumping 5.2lpm.  However, when I connected a pressure gauge to the output hose I noticed that the pressure had risen to 70+psi whereas before it was only 40psi.  So even though the volume didn't increase, the pressure did.  So I connected it to my RO and turned the speed of the pump right down with a PWM controller till the pressure switch stopped cutting in and out and it worked fine as a booster pump and has done so now for several years.  It only runs for about 8hrs a day about 4 days a week and stays fairly cool as it's running so slow, but it does the job.  I get better waste to pure ratio, and more importantly produce water at a rate that keeps up with my use.  My 300gpd RO struggles to keep up with me on only 40psi of water pressure - in winter especially.  The higher pressure also almost halves the output TDS reading of my RO, so my little 10" DI canister last ages, and that;s even with a tap TDS of around 400 most of the time.  All interesting stuff!

Can you paragraph my eyes are hurting trying to read your post  :1f602:

 

[Marko067]

Can you paragraph my eyes are hurting trying to read your post  :1f602:

You're right IG.  Just re-read it and it makes my eyes go funny as well.  Made an adjustment.  Hopefully it's a bit better now :1f44d: