gregzz4
07-04-2013, 04:20 AM
Nothing to panic over, but if you use a shut-off float valve on your RO holding tank ( as I do ) to shut off your system when the HT is full, this may apply to you ...
A few weeks ago I tested my HT water and found it to be a crazy 6PPM :surprise::redface:
That's nearly my City Water value
I washed out the drum (HT) and refilled it with a fresh run of 0 TDS from my RO only system. Since then I've topped it off a couple of times, so I've gone through approx 50g ? Doesn't matter
I tested the water in the drum this last weekend and found 2-4 TDS, depending on how the probe was positioned. I think these inline ones are sensitive to us ( interference ). Anyway , WTfudge :twised:
After some reading, and a bunch of PMs with 11purewater about Permeate Pumps, the cause and solution came about
Turns out that, because I use a float valve to close my RO water to the drum when it's full, the back-pressure on the Membrane kinda overwhelms it's ability to give me 0 TDS
What's happening is not really important. How it happens is
As the valve starts to close, it puts back-pressure on the Membrane and the TDS starts to climb
However long it takes for the valve to close is beyond me as I'm never around when it happens
Also, I have no idea what the TDS is when it's finally closed
But, I can tell you it must be very high. High enough to turn 45 gallons of 0 TDS RO water into 3-4 TDS crap :surprise:
To confirm this, I ran a simple test tonight ( Thanks for the idea Andy :mrgreen: )
I have an inline shut-off ( manual ) valve to my drum, and a Tee with another valve ( also manual ) that goes down the drain
I ran the system down the drain until I had 0 TDS. Then I opened the inline valve to the drum and closed the valve to the drain
Now the drum is being filled with 0 TDS RO water
Next, to simulate the float valve closing, I started closing the inline valve a bit at a time and, once it started to drip 4-6 drops/second, the TDS coming out of my Membrane started to climb :twised:
Who knows what kind of TDS I've been getting before the float valve in the drum is fully closed, but, as I stated above, it has to be HUGE to turn 45 gallons of 0 TDS RO water into junk
Suffice it to say I am going to revamp my system
I'll start by removing the float-shutoff valve and let the excess RO go down the drain until I shut off the water supply manually
In the near future I'll come up with a better way to turn off the system once the drum is full, but at least for now I found out where my TDS is coming from
And before someone jumps in and tells me to use a DI canister ...
I don't need one for my city water, so I'm not adding one just to solve this issue :wink:
A few weeks ago I tested my HT water and found it to be a crazy 6PPM :surprise::redface:
That's nearly my City Water value
I washed out the drum (HT) and refilled it with a fresh run of 0 TDS from my RO only system. Since then I've topped it off a couple of times, so I've gone through approx 50g ? Doesn't matter
I tested the water in the drum this last weekend and found 2-4 TDS, depending on how the probe was positioned. I think these inline ones are sensitive to us ( interference ). Anyway , WTfudge :twised:
After some reading, and a bunch of PMs with 11purewater about Permeate Pumps, the cause and solution came about
Turns out that, because I use a float valve to close my RO water to the drum when it's full, the back-pressure on the Membrane kinda overwhelms it's ability to give me 0 TDS
What's happening is not really important. How it happens is
As the valve starts to close, it puts back-pressure on the Membrane and the TDS starts to climb
However long it takes for the valve to close is beyond me as I'm never around when it happens
Also, I have no idea what the TDS is when it's finally closed
But, I can tell you it must be very high. High enough to turn 45 gallons of 0 TDS RO water into 3-4 TDS crap :surprise:
To confirm this, I ran a simple test tonight ( Thanks for the idea Andy :mrgreen: )
I have an inline shut-off ( manual ) valve to my drum, and a Tee with another valve ( also manual ) that goes down the drain
I ran the system down the drain until I had 0 TDS. Then I opened the inline valve to the drum and closed the valve to the drain
Now the drum is being filled with 0 TDS RO water
Next, to simulate the float valve closing, I started closing the inline valve a bit at a time and, once it started to drip 4-6 drops/second, the TDS coming out of my Membrane started to climb :twised:
Who knows what kind of TDS I've been getting before the float valve in the drum is fully closed, but, as I stated above, it has to be HUGE to turn 45 gallons of 0 TDS RO water into junk
Suffice it to say I am going to revamp my system
I'll start by removing the float-shutoff valve and let the excess RO go down the drain until I shut off the water supply manually
In the near future I'll come up with a better way to turn off the system once the drum is full, but at least for now I found out where my TDS is coming from
And before someone jumps in and tells me to use a DI canister ...
I don't need one for my city water, so I'm not adding one just to solve this issue :wink: