My Automatic Water Changer - Setup

[Betowess]

Steve, are you doing any fail safe stuff on the top off (inlet)? Like two of the float switches like I saw on one of the websites you linked me... And you might have already told me this... Are you running the 12/16mm or ~3/8 hose or pipe on that inlet side?
Is it the same 12/16mm hose for the drain? Thanks! bob

[Betowess]

He's not running RO, just tap, I believe.

[steve5520]

"are you doing any fail safe stuff on the top off (inlet)? "

No I'm not. It's just a single float switch. Maybe one day it will bite me, but the worst that can happen is for the tank to overflow. Since it's in the basement, the mess wouldn't be too bad.

I ran a top off on the reef setup I had for nearly 2 years, never even had to clean a float switch. I guess I'm figuring that salt and calcium would cause problems faster than freshwater, so I'm okay with a single float. If it were in my living room it might be a different story.

Try to make this concise:
Inlet side:
Float switch controls the level in the tank. Solenoid is hooked to cold tap water with 1/4 poly tube, same as an icemaker setup. My water pressure floats right around 50 psi and I estimate that the Clippard valve I'm using
http://www.clippard.com/store/displa...=MME-2QDS-W110
will pass around 50 - 60 gallons per hour. It only cycles on and off during the drain cycle.

Drain side:
Tee is in the return on my Filstar XP3.
Black Lightweight High-Density Polyethylene Tubing And Hose Tee Barb Fittings - US Plastic Corporation
Tee is 5/8 x 5/8 x 3/8
3/8 clear tubing runs to a solenoid valve.
AutoTopoff.com
Solenoid is controlled with a digital timer.

Volume of drain was obtain by timing how long to drain one gallon. After that, it was easy to figure how long I needed to leave the solenoid open.

RO water would not be as easy because of how slow it is produced. When I had the reef, I had a 100gpd ro/di. What most people forget is the 100gpd rating is at test pressure and temp, which I believe is 50 or 60 psi depending on who's membrane it is and 77 degrees. Lower pressure and temp will reduce ro production a LOT. With my 100gpd unit during winter months, I'd guess I was getting maybe 50-60 gpd. That's only 2.5 gal /hr

[Betowess]

Steve. I just printed out your PM and you had already covered almost all this- my bad - but at least its here for everyone. I might end up with Sergio's pressure water sensor, but I'm going to start with the auto top off to keep the cost down. This is quite doable and I am really happy about it. Thanks for sharing!!

[SuRje1976]

Originally Posted by steve5520

With my 100gpd unit during winter months, I'd guess I was getting maybe 50-60 gpd.

Steve - thanks for sharing! I just got my RO/DI unit in June, and I didn't even take this into consideration. I may need to adjust my timers to make sure the tank refills completely.

[steve5520]

Here's a link to a chart that you may find useful.

Calculating Expected GPD-LPD from the Reverse Osmosis RO Membrane by SpectraPure Water Purification Systems

As pressure drops, output drops. As temp drops, output drops. As far as I know, you cannot compensate for low temp by raising pressure.

One trick (cheap) that some reef guys do is to buy a coil of 1/4 poly tube, maybe 50 to 100 feet. Coil it up and put it in a bucket. Fill the bucket with water and stick and old heater in there set at around 78 degrees. It will warm the input water up and help maintain a little better output.
You can also find "mixers" to mix cold and hot water before entering the ro unit. From what I read, they aren't all that good. You need to be cautious too, water too hot will ruin the membrane.

[SuRje1976]

Originally Posted by steve5520

Here's a link to a chart that you may find useful.
You can also find "mixers" to mix cold and hot water before entering the ro unit. From what I read, they aren't all that good. You need to be cautious too, water too hot will ruin the membrane.

You know, the thought crossed my mind to tinker with ball valves set at specific levels of "open-ness" on the hot and cold line to achieve a specific temp to the RO/DI, but as my water chenges are done overnight, I don't think I'm going to run the risk of ruining a membrane. I'll just start the fill sequence at 6am, instead of 7am. Thanks again Steve for the info!

[Betowess]

Any thoughts on running 3/8 clear hose or is 3/8 RO hose similar for the drain. I don't want to chance a bend in the hose restricting flow. Which would be better, or does it even matter. I am leaning toward getting a Hobby pump like you have Sergio, since my distance will be around 22 feet give or take a few feet. Thanks for all the help Sergio! I'm about to start ordering components!!

[SuRje1976]

Originally Posted by Betowess

Any thoughts on running 3/8 clear hose or is 3/8 RO hose similar for the drain. I don't want to chance a bend in the hose restricting flow. Which would be better, or does it even matter. I am leaning toward getting a Hobby pump like you have Sergio, since my distance will be around 22 feet give or take a few feet. Thanks for all the help Sergio! I'm about to start ordering components!!

Bob - I don't think that it will make a difference except that you may have an easier time making your connections if you go with RO tubing. The John Guest line of adapters make plumbing the system pretty easy, and very leak resistant. PLUS, if you need to make a bend, you can buy things like this or this to prevent kinking. Obviously, if you have the room to make the larger diameter bend, go with that - it will have less effect on your flow rate.

One thing to keep in mind though is when you buy aquarium tubing/clear tubing, the size listed normally describes the INSIDE diameter of the tube (ID). When you are looking at RO, the measurments refer to the OUTSIDE diameter of the tubing (OD). So in that sense, they are NOT equivalent. If you wanted 3/8" ID, you would want to run with 1/2" RO tubing. That being said, I think 3/8" RO would be plenty, plus there is a wider range of fittings and adapters available than for the 1/2" RO.

I find that the drag created by the length of tubing I'm running (similar to what you'd run) to be very substantial. I really would recommend going with the pump. Just as a test, try blowing through a short length of tubing, say a foot, then try blowing through the length that you're going to run. The difference will be impressive.

Steve - thanks again for your input on the topic. It is helpful to everyone following the thread, myself included!

[Betowess]

Thanks Sergio. This is very helpful information.

[Betowess]

Now that the main components are ordered, I'm just now thinking about check valves...

OK, maybe one check valve per drain line before the drain saddles to keep any other drain water from the sink from contaminating the tank's drain line...

Also, one doesn't need one after the cannister's outflow T before the Hobby pump, right? My sequence is like yours, Filter/Hobby pump/solenoid ROline out for the drain.

But where else? Do I need one at the end of the fill line going back into the tank? Won't the solenoid stop any reverse siphon.

The fill sequence is: Tap - solenoid - into tank with water pressure making the push. Thanks, bob

[SuRje1976]

Originally Posted by Betowess

OK, maybe one check valve per drain line before the drain saddles to keep any other drain water from the sink from contaminating the tank's drain line...

Bob, this is what I have. Very close to the drain saddle.

Originally Posted by Betowess

Also, one doesn't need one after the cannister's outflow T before the Hobby pump, right? My sequence is like yours, Filter/Hobby pump/solenoid ROline out for the drain.

I don't have one here. Don't think it's necessary.

Originally Posted by Betowess

Do I need one at the end of the fill line going back into the tank? Won't the solenoid stop any reverse siphon.

The solenoid will definately stop reverse siphon, BUT I have one here anyway. Now I'm not a microbiologist, so I'm not sure if this is something I need to be concerned about, but the tip of the fill line is invariably going to come in contact with tank water at some point. I don't know how mobile any of the microorganisms in my tank are, but I don't want to run the risk of them "swimming" up the RO tubing to my RO/DI filter (which I also use for drinking water). I HATE vomiting.

[Betowess]

I copied this from another thread for those who are following it here...

I have jumped on the auto water change bandwagon. Total Cost shipped so far: for two 3/8" Asco Red Hat solenoids, two 1250 Hobby pumps, Ro line and drain/tap connections, inlet connections etc., float switches with relays and two more 1/4" RO solenoids from Autotopoff, four John Guest 3/8" RO line check valves, two 3/8" shutoff valves, etc is about $262.00 per tank...and counting.

I haven't added in the digital timers to the cost yet, and no doubt some other incidentals, like elec. cords and connections for the Asco solenoids for the drain cycle. This is going to be for a 90 gallon and a 65 gallon tank running around 22 feet of RO lines. Each system is independent. A little spendy, but I can't wait to see it in operation. I plan to do about 10% per day 5X a week. Then it will be just some fert dosing and trimming everyonce in a while, hopefully! Thanks for all your great help Sergio!! and Steve too!

[Brilliant]

Originally Posted by SuRje1976

You know, the thought crossed my mind to tinker with ball valves set at specific levels of "open-ness" on the hot and cold line to achieve a specific temp to the RO/DI, but as my water chenges are done overnight, I don't think I'm going to run the risk of ruining a membrane. I'll just start the fill sequence at 6am, instead of 7am. Thanks again Steve for the info!

Use a 3 way mixing valve

I thought this was up and runnig for a while. Are you using RO/DI water directly into the tank?

[SuRje1976]

Originally Posted by Brilliant

Are you using RO/DI water directly into the tank?

Yep...been running for a little over 2 months now I guess. RO directly into tank, with Equilibrium being dosed directly via autofeeder. I'm going to need to prepare for how the colder winter water is going to affect the time the tank will take to refill.