use rodi unit to ato from unit to upstairs tank

I was thinking about plumbing my Rodi unit in my basement 1/4" line to run up to my tank to a float valve. Will 60psi city water entering unit be able to push the Rodi water upstairs to my tank? not sure how much pressure is exiting unit (24gpd) i believe that its only about 9 to 10 feet up (vertical) from unit to tank. I was going to run unit on a timed interval of like 5 min per 2hr and adjust from there pending evap rate?

I recently installed mine next to and under the tank. I am using a float switch of my own design. I'm very happy with it.

But... we face similar issues. With me it is the fact that the dump line off the RO membrane has to push the waste water up about 8 feet and over to a toilet vent pipe. So far it hasn't seemed to be an issue... but how can I tell.. I guess in my case I need to climb into the attic and see if it is pushing water. No... wait.. ah.. I recall watching bubbles travel down that line during the start up.. wheew, I can breathe agan.. LOL.
I have full time presure on the other filters and put selonoid valve before the RO membrane so that it only gets presure when my float valve "requests" water. I used a micro switch up high with a push rod from the float so that the micro switch doesn't get any salt spray. I wired and designed the float switch so that fail mode is to NOT give water. I may can work up some pictures if someone is thinking to do a DIY as similar. I'm a retired machine design engineer so ... well.. I am and it is what we are. .. we all have our quirks.. wink. I'm always happy to share what I know or can do.. and I sure know I will be needing help learning to reef tank.

Yes - the RODI should be able to push the DI water up about 9 feet. Due to the head pressure your membrane will perform like it has about 60 psi rather than 65 psi - so you should be OK.

But you have a couple of other issues I'd be more concerned with:

1. We recommend against running your RODI to a float valve in your sump. When (not if) that float valve fails, or is kept from closing entirely by mineral build up, algae, a snail, etc, the RODI will pump 0 TDS water into your sump, and pump, and pump, and pump. If for whatever reason you don't catch this, you'll significantly change the salinity in your tank and overflow the sump. Bad news all around.

2. TDS Creep is a phenomenon common to all RO systems - it results in a pulse of not-so-clean water coming out of the system during the first 60 to 90 seconds after the system kicks on. Here's some data from two different tests that demonstrate TDS creep.



Every time your sump water level drops just a small fraction of an inch, the float will call for water and the RODI system will kick on for a short period of time. And then it will turn off. And on, and off, and on... all day long. We call this "short-cycling." When you allow a system to short cycle, a high percentage of the produced water has a TDS reading significantly higher than 0 ppm. So you end up burning through your DI resin faster than you should, and you deliver low quality water to your sump.

Russ

So.. you are saying that even though I have my "request" valve BEFORE the membrane I will be getting short cycle results.. I can see how this would be if I had the valve after the membrane... but don't see how that happens in my case... could you clear that up, please? With the out put at static pressure I realize the supply pressure will pulse against the supply end of the membrane but as tight as the membrane is it seems that blast would only be felt for a 1/2" or so into the membrane coil.

So do we recommend larger cycles of water less often? Timed cycles seem to me to be asking for problems.

My supply hose and valve into the tank can not be reached by snails as my water drips some 6 inches over the sump tank.

Seeing your point more clearly.. as I think through it.

SO?... thinking "on my feet"... I need to use two micro switches on my float demand switch system with a relay and wire them as a lock on toggle, so I can set both a turn on and a turn off level... thus a longer cycle of fill. (snails can't reach the electrics) I like that better anyway, because I AM getting some stuttering at the valve due to the ripples in the water at turn off.

.. though, please do expand more deeply for my knowledge bank.

So the same if I were to run my Rodi unit line to my top off reservoir rather than to my sump? then run my unit at a 4 hr span to fill the reservoir? still have the bad tds in the beginning because of no 2min flush right? Honestly i would rather run to my basement and set my timer to run 4 hrs to my top off reservoir then to keep lugging it upstairs every week lol

OK..at least I "think" my float switch design is snail proof.. guys & gals please take a look and see if I'm good or nutz... thanx.

The switch is at the top (black) and it is operated by the long brass push rod connected to the small rocker lever. I may make a plastic "dog bone" push rod when I get time to get the brass out of the eco system.

We could use a good snail proof design.. now to work on the toggle relay set-up so I can have a low and high water mark to stop the "short cycling". That would be the perfect time to install a plastic push rod.

This place ROCKS. We are all SO much smarter together!

Geeeze Buckeye.. when you are right you are right... my valve just stuttered horribly.... I'm on it.. but please still expand on the bad stuff when we turn the membrane flow off and on.


SO... do I need to move this thread to the DIY section and can a moderator push it that direction? ..and then tell this nut how to find it after it is moved. I never intended to steal the thread.

I've already spanked my hand for not doing that.. but being a newbee... oops...

Poksal - my comments were directed at salt01 - the original poster...

poksal said:

So do we recommend larger cycles of water less often?

Click to expand...

Yes sir - fewer longer cycles are better.

SO?... thinking "on my feet"... I need to use two micro switches on my float demand switch system with a relay and wire them as a lock on toggle, so I can set both a turn on and a turn off level... thus a longer cycle of fill. (snails can't reach the electrics) I like that better anyway, because I AM getting some stuttering at the valve due to the ripples in the water at turn off.

.. though, please do expand more deeply for my knowledge bank.

Click to expand...

This may help:



Russ

Russ, yes.. it does help.. so that way I get to keep my sump depth difference tight. I see me doing some electronic play time building the system.... that is cool.
Plus it provides and suggests a fail safe redundancy.

Being who I am and a hard core DIY'er I see me using a relay latch circuit at the RO supply tank..... and a fail safe method... and building so that an electric failure faults to no flow. That requires no changes for me at the sump except for where the water comes from.

Thanx
-randy-

The sytem above has two failsafes - the float valve in the RO reservoir, and use of a normally closed solenoid.

Russ

Got ya.. normally closed is usually the default condition of a liquid valve. Also, I suppose a person could use a toilet float valve system as the final safety stage of the input to the RO storage tank. It has it's own bulkhead connector and will not fill if full if adjusted right. However, they (the currently popular ones have a diaphram) do take back pressure to operate. I am not going to do that.. but it did raise the question in my brain... how would that kind of back pressure effect the RO membrane filter's physics?

I know there are several reef tankers that use a toilet valve as the fill control to their RO tank.. here again we are short cycling.

I'm working on my version of the one in the drawing right now.... I think I live to tinker...

-randy-

I have a similar tinkering disease.

Any back pressure on the membrane changes the delta between the high pressure side of the membrane and the low pressure side - and reduces what's called the Net Driving Pressure.

yeah. that "figures".

...no, I call it a blessing.. my wife calls it a plauge... LOL... yeah.

I LOVE to design DIY's and it is the challange.. and the snowballing of skills as they stack and build on each other that seems to drive it. AND the high of satisfaction when something works as planned.

I took a break and am eating pizza and watching Yipe Out.

I have/had a large leather coral that was not doing so well. I took a clean paint brush and gently brushed off the slime... it clouded my tank... oops... anyway I think that is what did it... am I right and how big of a mistake was that???

I removed the leather because it had turned loose of the rock and I got scared that it was poluting my tank... help me here..

I've got sooo much to learn!

poksal said:

I have/had a large leather coral that was not doing so well. I took a clean paint brush and gently brushed off the slime... it clouded my tank... oops... anyway I think that is what did it... am I right and how big of a mistake was that???

I removed the leather because it had turned loose of the rock and I got scared that it was poluting my tank... help me here..

I've got sooo much to learn!

Click to expand...

You'll have better luck getting responses if you start a new thread with this question.

That being said if it let go of the rock, IMO I'd say it's too far gone.

Will do.. thanx ..I thought so too.

I have my RODI tank which holds about 3 days worth of ATO, and my gravity feed ATO from that tank, up and running. Thanks to help from Living Reef.

I just wish I could do as well figuring out the living and eco portions of this hobby as well as I handle the physics, and mechanics.

Please be patient with me as I struggle along.