RO/DI prime system

sleepydoc · 08/20/2017, 01:53 PM

Does anyone know of a commercially available controller for an RO/DI system? I'm thinking of something that would open a valve after the RO membrane for xx minutes to allow the membrane to warm up to peak efficiency, then close that valve and open a solenoid after the DI membrane, possibly with the entire thing controlled by float valves in the reservoir.

I haven't found anything in my searching, so I may have to DIY it with a 555 timer circuit or an Arduino.

mcgyvr · 08/20/2017, 01:55 PM

None specifically for RO/DI systems that I've seen but all that is something a normal reef controller would/could handle..
You could use an ATO system and a time delay relay too.. or roll your own..

Make sure you are ok with an endless potential supply of water to your tank..

sleepydoc · 08/20/2017, 02:23 PM

This won't be connected to my tank; it's just for my RO/DI system. Currently I have a Tee between the RO membrane and the DI canister to serve as a bypass to prevent TDS creep. When I want to make some DI water, I open a valve coming off the tee and let water run through the RO membrane until the Post RO/Pre DI TDS settles, then I close that valve and open up the valve coming off the DI resin to start making DI water.

Just looking to automate that process. I have an Apex, but it's in the other room with my tank so I'd either have to run 50 foot cables or get a second controller, but a full controller is overkill for this.

mcgyvr · 08/20/2017, 04:24 PM

just need a few relays (ice cube type or whatever) really depending on the logic you want.. 1 time delay too..
or an arduino or esp
http://www.electrodragon.com/product...based-esp8266/

I personally never worry about TDS creep when filling up decent amounts of water.. Even when I fill 5G buckets I just turn the system on.. I never really notice any negative effects from TDS creep personally.. output is always 0 TDS.. But I don't check TDS post membrane.. Just in and out.. and I get plenty of life out of my DI resin.. That little bit just gets diluted right down..

ravi197699 · 08/20/2017, 04:26 PM

Here you go, Here is the RO/DI system that flushes the membrane for 18 seconds before it starts producing wate.. I hope this is what you are looking for..

http://www.ebay.com/itm/RO-Reverse-O...19.m1438.l2649

der_wille_zur_macht · 08/20/2017, 08:46 PM

This is a fun basic logic puzzle.

You basically need three states: 1) everything off, 2) flush line on and main supply line to DI off, 3) main supply to DI on, flush line off.

Use two float switches in the reservoir per the norm, one at the bottom and one at the top, set up to latch. This latching circuit is connected to two relays. The first is a time delay relay with double throw. One side powers a solenoid off the tee between RO and DI (which empties to a drain, this is your flush water). The other throw powers a solenoid between the DI and the reservoir. The latching circuit is also connected to a second (normally open) relay that is between the two solenoids and ground, and acts as a master switch.

This way, at rest, prior to the latching circuit being tripped, you are in the first state. The second relay is keeping both solenoids off. When the vessel empties and the bottom float triggers the latching circuit and powers both relays, you enter the second state. You are flushing the membrane for the duration of the timer. When the timer expires and the time delay relay switches, you enter the third state - the flush line is shut off and the line supplying the DI (and eventually the reservoir) is opened. When the reservoir fills up and trips the top float in your latching circuit, you return back to the first state, everything is shut off.

If you can't find a double pole time delay relay, use a plain old single pole time delay relay with a pair of other relays - one NO and one NC - to get both functions you need.

sleepydoc · 08/22/2017, 04:25 PM

Quote:

Originally Posted by der_wille_zur_macht

This is a fun basic logic puzzle.

You basically need three states: 1) everything off, 2) flush line on and main supply line to DI off, 3) main supply to DI on, flush line off.

Use two float switches in the reservoir per the norm, one at the bottom and one at the top, set up to latch. This latching circuit is connected to two relays. The first is a time delay relay with double throw. One side powers a solenoid off the tee between RO and DI (which empties to a drain, this is your flush water). The other throw powers a solenoid between the DI and the reservoir. The latching circuit is also connected to a second (normally open) relay that is between the two solenoids and ground, and acts as a master switch.

This way, at rest, prior to the latching circuit being tripped, you are in the first state. The second relay is keeping both solenoids off. When the vessel empties and the bottom float triggers the latching circuit and powers both relays, you enter the second state. You are flushing the membrane for the duration of the timer. When the timer expires and the time delay relay switches, you enter the third state - the flush line is shut off and the line supplying the DI (and eventually the reservoir) is opened. When the reservoir fills up and trips the top float in your latching circuit, you return back to the first state, everything is shut off.

If you can't find a double pole time delay relay, use a plain old single pole time delay relay with a pair of other relays - one NO and one NC - to get both functions you need.

Yes - This is exactly what I had envisioned. I was just wondering if it already existed or if I needed to make it myself. It's looking like I need to make it myself.

As an additional modification, if you put a momentary pushbutton switch in parallel to the bottom float in the RO/DI reservoir, you could trigger the system at any time.

I'll have to look at the circuits. I have an Arduino sitting on the shelf that I could also use - of course I'd still need to get some parts to interface the Arduino with the relays, so I might be just as well off building it from scratch.

der_wille_zur_macht · 08/22/2017, 06:56 PM

I would skip the arduino unless you just really want to use it. The only "advanced" problem you have to solve is the time delay, and there are relays off the shelf for that. Otherwise it's just a bunch of straightforward logic. Adding a processor won't really reduce parts count since since you still need the float switches and relays and solenoids.

Scrimpie · 08/22/2017, 07:02 PM

There is an auto flush system.

Mark Bianco · 08/26/2017, 09:50 AM

Something like this? https://www.bulkreefsupply.com/aquat...estrictor.html

Would this work for your application?

RWEngineer · 08/26/2017, 11:22 AM

I would be interested in what you come up with.
I did it with a hi low tank controller then added a delay relay to the output so I could dispose the first 2 minutes of RO water down the drain.

Those of you that have suggested an auto flush kit. He is not trying to flush the membrane.

08/20/2017, 01:53 PM	#1
sleepydoc Registered Member Join Date: Oct 2011 Location: Minneapolis, MN Posts: 3,907	RO/DI prime system Does anyone know of a commercially available controller for an RO/DI system? I'm thinking of something that would open a valve after the RO membrane for xx minutes to allow the membrane to warm up to peak efficiency, then close that valve and open a solenoid after the DI membrane, possibly with the entire thing controlled by float valves in the reservoir. I haven't found anything in my searching, so I may have to DIY it with a 555 timer circuit or an Arduino. __________________ ~~~~~~~~~~~~~~~~~~~~~ 120 gallon, coast to coast overflow w/beananimal overflow. Waveline DC 10000 II return pump, 40 gal sump, Octopus XS200 skimmer, T5 lighting

08/20/2017, 01:55 PM	#2
mcgyvr Registered Member Join Date: Sep 2003 Location: North Carolina Posts: 20,050	None specifically for RO/DI systems that I've seen but all that is something a normal reef controller would/could handle.. You could use an ATO system and a time delay relay too.. or roll your own.. Make sure you are ok with an endless potential supply of water to your tank.. __________________ Who me?

08/20/2017, 02:23 PM	#3
sleepydoc Registered Member Join Date: Oct 2011 Location: Minneapolis, MN Posts: 3,907	This won't be connected to my tank; it's just for my RO/DI system. Currently I have a Tee between the RO membrane and the DI canister to serve as a bypass to prevent TDS creep. When I want to make some DI water, I open a valve coming off the tee and let water run through the RO membrane until the Post RO/Pre DI TDS settles, then I close that valve and open up the valve coming off the DI resin to start making DI water. Just looking to automate that process. I have an Apex, but it's in the other room with my tank so I'd either have to run 50 foot cables or get a second controller, but a full controller is overkill for this. __________________ ~~~~~~~~~~~~~~~~~~~~~ 120 gallon, coast to coast overflow w/beananimal overflow. Waveline DC 10000 II return pump, 40 gal sump, Octopus XS200 skimmer, T5 lighting

08/20/2017, 04:24 PM	#4
mcgyvr Registered Member Join Date: Sep 2003 Location: North Carolina Posts: 20,050	just need a few relays (ice cube type or whatever) really depending on the logic you want.. 1 time delay too.. or an arduino or esp http://www.electrodragon.com/product...based-esp8266/ I personally never worry about TDS creep when filling up decent amounts of water.. Even when I fill 5G buckets I just turn the system on.. I never really notice any negative effects from TDS creep personally.. output is always 0 TDS.. But I don't check TDS post membrane.. Just in and out.. and I get plenty of life out of my DI resin.. That little bit just gets diluted right down.. __________________ Who me?

08/20/2017, 08:46 PM	#6
der_wille_zur_macht Team RC Member Join Date: Sep 2003 Location: NY Posts: 17,749	This is a fun basic logic puzzle. You basically need three states: 1) everything off, 2) flush line on and main supply line to DI off, 3) main supply to DI on, flush line off. Use two float switches in the reservoir per the norm, one at the bottom and one at the top, set up to latch. This latching circuit is connected to two relays. The first is a time delay relay with double throw. One side powers a solenoid off the tee between RO and DI (which empties to a drain, this is your flush water). The other throw powers a solenoid between the DI and the reservoir. The latching circuit is also connected to a second (normally open) relay that is between the two solenoids and ground, and acts as a master switch. This way, at rest, prior to the latching circuit being tripped, you are in the first state. The second relay is keeping both solenoids off. When the vessel empties and the bottom float triggers the latching circuit and powers both relays, you enter the second state. You are flushing the membrane for the duration of the timer. When the timer expires and the time delay relay switches, you enter the third state - the flush line is shut off and the line supplying the DI (and eventually the reservoir) is opened. When the reservoir fills up and trips the top float in your latching circuit, you return back to the first state, everything is shut off. If you can't find a double pole time delay relay, use a plain old single pole time delay relay with a pair of other relays - one NO and one NC - to get both functions you need. __________________ Inconveniencing marine life since 1992 "It is my personal belief that reef aquaria should be thriving communities of biodiversity, representative of their wild counterparts, and not merely collections of pretty specimens growing on tidy clean rock shelves covered in purple coralline algae." (Eric Borneman)

08/20/2017, 04:26 PM	#5
ravi197699 Registered Member Join Date: Oct 2011 Posts: 567	Here you go, Here is the RO/DI system that flushes the membrane for 18 seconds before it starts producing wate.. I hope this is what you are looking for.. http://www.ebay.com/itm/RO-Reverse-O...19.m1438.l2649

08/22/2017, 06:56 PM	#8
der_wille_zur_macht Team RC Member Join Date: Sep 2003 Location: NY Posts: 17,749	I would skip the arduino unless you just really want to use it. The only "advanced" problem you have to solve is the time delay, and there are relays off the shelf for that. Otherwise it's just a bunch of straightforward logic. Adding a processor won't really reduce parts count since since you still need the float switches and relays and solenoids. __________________ Inconveniencing marine life since 1992 "It is my personal belief that reef aquaria should be thriving communities of biodiversity, representative of their wild counterparts, and not merely collections of pretty specimens growing on tidy clean rock shelves covered in purple coralline algae." (Eric Borneman)

08/22/2017, 07:02 PM	#9
Scrimpie Registered Member Join Date: Aug 2017 Posts: 10	There is an auto flush system.

08/26/2017, 09:50 AM	#10
Mark Bianco In Memoriam Join Date: Nov 2011 Location: Infinity and Beyond Posts: 2,445	Something like this? https://www.bulkreefsupply.com/aquat...estrictor.html Would this work for your application?

08/26/2017, 11:22 AM	#11
RWEngineer Registered Member Join Date: Aug 2015 Posts: 120	I would be interested in what you come up with. I did it with a hi low tank controller then added a delay relay to the output so I could dispose the first 2 minutes of RO water down the drain. Those of you that have suggested an auto flush kit. He is not trying to flush the membrane.