Mixing valve of some sort?

[fishguy306]

Have a bit of an odd situation, hoping someone here might have some experience.

I'm on the hunt for a valve or some sort of device to mix water much like a thermostatic mixing valve, but rather than based on temp I need it based on quantities.

Situation is, we are making very large quantities of RO water, somewhere around 1000 gal of it, then need to add just a bit of tap for buffering. Not sure how much exactly, maybe 10 gal of RO for every 1 gal of tap. At the moment we have the RO fill the storage tank, then top off the tap water manually.

We'd really like to automate this process, either with a valve that can be adjusted to the amount we need, or we are using an Apex, if that'll work in some way. Willing to spend some money to get this right. I realize this isn't a typical reef situation but when it comes to RO and aquarium plumbing problems there is nowhere better to ask.

 

[Vinny Kreyling]

My choice?
LitreMeter by Spectrapure
Can pump up to 26 gallons a day in increments of 150 times daily.
More than enough for your application.

 

[neilp2006]

Why not use an apex BOB with float switches controlling the RODI and a solenoid on a Tee at the rodi input to supply the tap water.

First float cuts off the RODI, then the same float opens up the solenoid for the tap water (basically a tee in the input with the solenoid essentially opening a bypass fir the rodi) . Second float cuts off the solenoid.

Positioning would be pretty simple- first float at 900 gallons capacity, second one positioned at the 1000 g capacity point. This'll give you 9:1 rodi to tap, or a 10% tap water in rodi mix.

Add safeties as appropriate.


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[neilp2006]

My choice?
LitreMeter by Spectrapure
Can pump up to 26 gallons a day in increments of 150 times daily.
More than enough for your application.

He's planning to make 1000 gallons... don't think he can wait 5 weeks to do the ratios


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[Vinny Kreyling]

@ 11.1 gallons per 100 he is done when full.

 

[neilp2006]

@ 11.1 gallons per 100 he is done when full.

Ok, gotcha.

Essentially dosing tap water from a secondary container.


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[fishguy306]

My choice?
LitreMeter by Spectrapure
Can pump up to 26 gallons a day in increments of 150 times daily.
More than enough for your application.

This is an interesting one, though I see a couple potential hangups. I assume I'd need a separate storage tank with the tap water for the LitreMeter to pull from to add to the RO? That isn't a huge issue, my bigger issue would be making sure it adds the tap at the right time. With RO production not always being consistent would like for a way to make it so RO hits a certain level which would trigger the addition of the tap water. Maybe float valves throughout the storage container?

Why not use an apex BOB with float switches controlling the RODI and a solenoid on a Tee at the rodi input to supply the tap water.

First float cuts off the RODI, then the same float opens up the solenoid for the tap water (basically a tee in the input with the solenoid essentially opening a bypass fir the rodi) . Second float cuts off the solenoid.

Positioning would be pretty simple- first float at 900 gallons capacity, second one positioned at the 1000 g capacity point. This'll give you 9:1 rodi to tap, or a 10% tap water in rodi mix.

Add safeties as appropriate.

I have considered this method, it is similar to what we are doing now. Fill to the float valve with RO, then top off manually with tap. Biggest issue is if we don't use all the water in one go. We'll be doing massive water changes but a lot of this is just to have water on hand in case of emergency, so say we use 500 gal out of the 1000, RO fills back up, then the tap, tap water levels are now higher since the previously mixed amount didn't get fully used.


I'm not sure I'll ever find a perfect solution for this. Was hoping to keep things simple, but at this point I'm thinking mixing up a buffer might just be easier than trying to mix some tap back in at consistent levels.

 

[neilp2006]

Yep- my method would require complete consumption. No sure how to go about variable tap water volumes like this.


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[Vinny Kreyling]

Probably a 55 gallon container marked in gallons that you could use as much or little as needed & refill.

 

[Tastee]

I have considered this method, it is similar to what we are doing now. Fill to the float valve with RO, then top off manually with tap. Biggest issue is if we don't use all the water in one go. We'll be doing massive water changes but a lot of this is just to have water on hand in case of emergency, so say we use 500 gal out of the 1000, RO fills back up, then the tap, tap water levels are now higher since the previously mixed amount didn't get fully used.

Perhaps you could mount your second float on an adjustable rod with graduated markings. That way you could raise or lower it depending on how much water you are replacing to control the amount of tap water you are adding.

Rather than connect this to a tap water reservoir you could have mains supply connected, but I would introduce a second solenoid daisy-chained to protect against a fail on.



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[tkeracer619]

The easy solution is to get an adjustable masterflex peristaltic pump. Run it at the same time as your RODI. Measure the rate your RODI produces and set the masterflex to run 10% of that. Have it pull from a small reservoir with a float valve connected to the cold water line.

The real question is why put tap back into RODI? If you are just trying to buffer use the peristaltic to pull from a 5 gal bucket of buffer the same way. This way you aren't getting impurities.