Need help with sump/fuge

[TheReefGeek]

Can't tell much from the picture, but I don't think that will control your RODI unit.

If you want to run your RODI unit to float valves, you will have to rely on pressure in the line (created when the float valve closes) to trigger a diaphram in a hyraulic valve plumbed right into your RODI unit. It is actual the pressure difference on the two sides of the diaphram that triggers it to shut off water to the RODI, thus cutting off waste water production as well. BUT, if your line between the RODI and the float valve(s) is too long, you will have to install pressure bladders (check out spectrapure systems for an example of these) to create enough pressure to trigger the diaphram to flip.

The other way is to control it electronically with float valves. Very possible but I have had too many fail open to trust them anymore myself.

[Willow]

you know the aquasafe units have a built in auto shut off unit. i still wouldnt hook it directly to my tank but you could.

[Delphinus]

It's not necessarily a good idea to hook up the RO/DI to a tank anyhow, even if you have the solenoid shutoff control. The problem is that the evaporation rate is 24/7, so you would be constantly cycling the RO/DI on and off for short bursts. And actually, a higher GPD rating of the membrane compounds this, as you'll have it on for only a few seconds at a time before the level is maintained again. This is murder on a RO membrane and will contribute to early failure of the membrane.

As far as I'm concerned, the auto shutoff feature of a RO/DI unit should be used to avoid spillage when filling your reservoir. I.e. if it takes 10 hours to fill your reservoir you can just turn it on and forget about it, not have to worry about remember 10.5 hours later that you now have an overflowing reservoir.

You could probably make it a little better by expanding your deadband by creative use of float switches but even then .. it's still the same problem of repeated on/off cycles. I.e., say 40gpd replacement water per week, your membrane will last you much longer if you do one production run of 40g instead of 100 production runs of .4g.

Thus my recommendation is float valves on your sump fed by a reservoir, RO/DI only to fill the reservoir using a float valve on the reservoir and the auto shutoff kit on the RO/DI as a luxury item to afford you peace of mind when manually filling that reservoir as needed.

PS. My $0.02 as far as float valves failing .. generally speaking this is a very rare occurence if set up properly and maintained regularly with diligence. Also the likelihood of failing is more in the nature of a clog, rather than failing stuck open. So if you find your float valve clogged, you just clean it and away you go.

[albert_dao]

Originally Posted by Delphinus

OH LOOK AT ME, I'M TONY AND I HAVE 5700 POSTS.

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Well Tony, I don't know what to say to that.

[Delphinus]

Uh .. Ok, I'm not really sure how to take that. Um .. haha?

[albert_dao]

Originally Posted by Delphinus

Uh .. Ok, I'm not really sure how to take that. Um .. haha?

Just bangin on ya Tony, haha :P

[TheReefGeek]

This is murder on a RO membrane

This is why I use a timer, my RODI kicks on once a day only.

[Delphinus]

I see. I guess that's not too bad, although I still think I like my idea of using the reservoir better. There's no deviation in the salinity (although I agree that the deviation in your scenario is likely negligible). Certainly if you don't have the space for a reservoir, that is a workable solution, although seems to me it involves more components and is just a "tad" more complex.

[mark]

Was going to be gone for a few days so wanted something quick so rather than playing around with solenoids, relays etc without a period of testing just got a humidifier float and hooked directly to rodi.

Understand the reasoning for a small volume reservoir if float fails open and still might go that route but this is working prefect for now.