The big question: can you use tap water to top-off?

[worley]

Into an open bucket, however, it's going through around 30ft of tubing to get there, but the flow is still the same even if the clean water outlet cable is only 3ft there's still the same ratio (I've not actually measured, but the flow looks the same).

[kcress]

Yeah it would be the pretty much the same. I was asking because they are substantially less efficient,(but infinitely more useful), with a bladder tank allowing domestic use.

You should get your restrictor correct before anything else.

[worley]

Well, I've simply put an inline valve on the waste output and adjusted it to slow the waste flow, it is now producing water at least twice as fast now
I measured the outputs:
200ml clean water
700ml waste water
so 1:3.5, probably as close as I'm going to get as the valve is very sensitive
380ppm TDS in, 6ppm TDS out. Which gives a 98.4% rejection rate.
This is after 9 months of using the filter fairly heavily and not replacing the pre-filters, so it's probably about time, it was at 1-2ppm TDS to start with. Thanks for the help

[kcress]

Great that's a fine solution.

And yes, using a valve is usually really touchy. Glad you got it dialed. And 3.5:1 is just fine.

I usually start changing things when the TDS get's to 10ppm. Everything changed, I get 0 to 1ppm. But my tap water is only about 240ppm. After the carbon block is about 150ppm.

[ocean rock]

i there i have a veggie patch at the side of the shed were i do all my jobbing " mixing salt , test meters , you now all the things that go with keeping a little bit off reef in a glass box " any way the ro unit is piped up in the shed , and the waste water runs into a water butt " 75 gallon " this i then use on my sweet corn and rhubarb , so no water is wasted ,

[worley]

We've got a large water butt outside too, but it's completely full from when I moved the 3x2x2 into the 6x2x2 and had to make up 50% of the water, that would have filled the water butt up 3 times over, not really used much of the water in there, after all, we're in a flat and only have a raised patio area + potted plants lol.