Balancing RO

[McDirty]

Morning all,

Yesterday I finally got my static system up and running.

When balancing the waste vs pure I’m not getting 50/50 or 60/40 but my tds is coming down from 97 to 1 pre resin.

Am I thinking too much into this balancing aslong as I’m producing waste and my tds is sitting as low as possible shall I just let it run like that?

Cheers

 

[spruce]

Morning all,

Yesterday I finally got my static system up and running.

When balancing the waste vs pure I’m not getting 50/50 or 60/40 but my tds is coming down from 97 to 1 pre resin.

Am I thinking too much into this balancing aslong as I’m producing waste and my tds is sitting as low as possible shall I just let it run like that?

Cheers

Yes

 

[McDirty]

Yes

Thanks Spruce.

 

[spruce]

Thanks Spruce.

What you are doing is finding your r/o's sweet spot where it works the most efficiently. For someone to achieve that they need to start somewhere. We generally suggest a starting point is adjusting the waste to pure ratio somewhere between 50/50 and 60/40 for soft to medium water. I found that my r/o's sweet spot is approx 55 waste to 45 pure. That gives me a rejection rate of 97%. If I throttle the waste back even slightly more my tds will rise. If I open the waste valve to say 60/40 then my rejection rate will stay at 97%. So I will go for the lowest water to waste adjustment to save water. If you are on a water meter, every drop saved is a cost saving.

I have an inline water meter with 2 sensors, one on the r/o outlet before DI and the other after DI. It's been years since I have actually measured my waste to pure ratio.

This is what works for me with our water pressure of 55psi. The water temperature is ever so slightly warmer than it was last month, so I have to regularly make small adjustments to the waste valve.

 

[McDirty]

What you are doing is finding your r/o's sweet spot where it works the most efficiently. For someone to achieve that they need to start somewhere. We generally suggest a starting point is adjusting the waste to pure ratio somewhere between 50/50 and 60/40 for soft to medium water. I found that my r/o's sweet spot is approx 55 waste to 45 pure. That gives me a rejection rate of 97%. If I throttle the waste back even slightly more my tds will rise. If I open the waste valve to say 60/40 then my rejection rate will stay at 97%. So I will go for the lowest water to waste adjustment to save water. If you are on a water meter, every drop saved is a cost saving.

I have an inline water meter with 2 sensors, one on the r/o outlet before DI and the other after DI. It's been years since I have actually measured my waste to pure ratio.

This is what works for me with our water pressure of 55psi. The water temperature is ever so slightly warmer than it was last month, so I have to regularly make small adjustments to the waste valve.

Thanks for this great reply.
I’ll have another play later and get it just right.
I have a water meter on the inlet so I know when to change the pre filters. Didn’t think to put one further down the system.

 

[spruce]

Thanks for this great reply.
I’ll have another play later and get it just right.
I have a water meter on the inlet so I know when to change the pre filters. Didn’t think to put one further down the system.

You only need a single water meter tbh. You need to monitor how much water your r/o uses (waste + pure) to determine when to change your carbon block filter. If you are on a water meter then a second water meter could be a consideration as your water board should refund you the sewerage charge on the pure you take away.

If all your waste water goes to a soak away, then they should refund the sewage charge on all the water your r/o processes. In that case, a single approved water meter would be all that's needed. (Not all water authorities will refund window cleaners the sewerage element of our water costs. For example, the last time I checked, Northumbrian water on Teesside would not. I asked from a sole trader's view point; maybe a business operating from an industrial unit would be treated differently.)