Unique Auto-Water Change

[josh26757]

Reason
OK, I am very happy with water quality and the stability that has been added since I plumbed the tank to the basement. The RO/DI system works on a float and automatically tops off the water by itself thus being maintenance free. I am trying to address any issues in regards to stability with the next being water changes. Equal salinity and temp while providing a gradual change is my goal, so here is the idea.

Idea
The basement sump is a split design waterfalling to the center. In the center is the return with the auto-topoff. The water level is maintained consistently all day by the ro/di. I want to drill a hole right at the sump return level and place a bulkhead that drains outside. It just so happens that the sump is setting against an exterior wall where my AC runs.

This drain will have a normally closed valve being held open by a power supply. The reason for this is the water level in the sump will rise when the electric goes out and therefore the valve will close to allow this. The valve will be on a 30 sec timer on startup to allow the water to level out in the sump. The same controller (Arduino) controlling the valve will use a small pump and run 1 1/2 gallons a day into the sump thus causing an overflow into the drain and changing 10.5 gallons a week. I have a 44 gallon container that will allow 4 weeks of water changes before having to mix more.

Concerns
The best side is if the pump fails the worst that can happen is I get a 40 gallon water change and burn up a cheap pump. As far as the valve goes I will use a high quality brass valve and the saltwater will not contact it unless the electric goes out (the valve will close causing contact) and that only happens a couple times a year.

Reason For Posting
Do you see any flaws in the concept here? Are there any concerns that you would have that I may not be considering? I want to start working on this Monday/Tuesday, but want to be sure I make all possible considerations before passing the point of no return (drilling).

 

[Mrramsey]

Interesting... Will be following along.

What do you do about condensation in the mix tank possibly throwing the salinity off?

 

[josh26757]

Interesting... Will be following along.

What do you do about condensation in the mix tank possibly throwing the salinity off?

Has never been a problem thus far, but will definitely keep an eye on that. Before now I always tested it before performing the change. Another advantage of doing small changes is any parameter swing from salt mix or simple unforeseen variable such as this one is going to be very gradual. Should give me plenty of time to say, "Hey my salinity is almost a point higher". I will definitely be doing a lot of testing right out of the gate to be sure there are no surprises.

 

[Laardvark]

I would be concerned about the effects of salt water on the brass valve over time. Even though it would not be in constant contact with the water I would be very concerned about corrosion eventually seizing up the valve, especially if it's only activated intermittently.

I'm confused why you would use a pump to add 1.5 gallons to the sump then use a gravity drain to outside? It's kind of fun building all kinds of automation but I think this over complicates things without yielding a benefit (am I missing something here?).

Why not plumb the pump to the bulkhead and discharge the 1.5 gallons directly outside? This wouldn't call for anything you don't already need with your plan, and would eliminate one potential failure point.

In this hobby overly complicated systems just don't pay dividends. A more reliable and probably cheaper method (although maybe you got an activated brass valve from somewhere and that's why you want to use it?) would be to get 2 small powerheads- one in the sump pumping outside, one in the salt mixing station pumping to the sump (although you could use an all-plastic solenoid valve + gravity feed from the salt tank if you wanted- McMaster-Carr has them for ~$60).

I don't mean to dis your idea, I just don't see how it provides an advantage over tried and true methods, while it does introduce more things that can go wrong. HTH

 

[Mark Bianco]

"I will use a high quality brass valve" Brass consists of about 98% cooper and the rest zinc and a few other trace elements. Last I knew cooper will kill corals. How much is going to be given off from the valve I have not a clue. but then again IMO why risk it. There are some high quality plastic valves and some stainless steel valves, if you want to look into them.

Mark

 

[josh26757]

I would be concerned about the effects of salt water on the brass valve over time. Even though it would not be in constant contact with the water I would be very concerned about corrosion eventually seizing up the valve, especially if it's only activated intermittently.

I'm confused why you would use a pump to add 1.5 gallons to the sump then use a gravity drain to outside? It's kind of fun building all kinds of automation but I think this over complicates things without yielding a benefit (am I missing something here?).

Why not plumb the pump to the bulkhead and discharge the 1.5 gallons directly outside? This wouldn't call for anything you don't already need with your plan, and would eliminate one potential failure point.

In this hobby overly complicated systems just don't pay dividends. A more reliable and probably cheaper method (although maybe you got an activated brass valve from somewhere and that's why you want to use it?) would be to get 2 small powerheads- one in the sump pumping outside, one in the salt mixing station pumping to the sump (although you could use an all-plastic solenoid valve + gravity feed from the salt tank if you wanted- McMaster-Carr has them for ~$60).

I don't mean to dis your idea, I just don't see how it provides an advantage over tried and true methods, while it does introduce more things that can go wrong. HTH

I am not sure you understand. It is the same concept as the overflow from the main dt to a sump, just I am running fresh saltwater in and allowing the old to drain directly outside. This also removes the second pump and removes problems trying to match head pressure/flow on each one.

 

[josh26757]

I do have access to free brass valves that are very reliable (and expensive) but I was also looking at these and just putting two inline.

http://www.ebay.com/itm/1-4-NPT-Ele...425?pt=LH_DefaultDomain_0&hash=item43b075ab59

 

[josh26757]

I tried to throw a quick drawing together to be sure we are all on the same page

 

[josh26757]

"I will use a high quality brass valve" Brass consists of about 98% cooper and the rest zinc and a few other trace elements. Last I knew cooper will kill corals. How much is going to be given off from the valve I have not a clue. but then again IMO why risk it. There are some high quality plastic valves and some stainless steel valves, if you want to look into them.

Mark

The valve is on the drain and will never come into contact with water used in the tank.

 

[josh26757]

Additional notes, trying to dodge the battle of a qt tank I bought my fish about the same time and added them into the tank. Uh, bad idea. I have lost three fish and the others are not doing well to say the least. It really looks like velvet. Anyway that is my problem, but I was thinking about this design and thought I could use this to run a QT tank almost full time (minus heater, lights, sponge filter). I could overflow the sump and let that fall into the QT that would inturn flood out the drain. Any additional WC needed could be done from the holding container, but still will require little maintenance. As I could use a DT now this may just be happening this week.

 

[ca1ore]

The valve is on the drain and will never come into contact with water used in the tank.

In the event of a power failure it will! I just think using any copper-based metal in or around a reef tank is a bad idea. I'd definitely go plastic if it were me. The other thing I'd worry about is a actuator that is being held semi-permanently in a powered state. Not sure how long such an actuator would last, but I'd be inspecting it regularly.

BTW, using a direct plumbed RO/DI system for ATO is not something I would do. Runaway ATO is right there with a stuck heater for #1 reason for a tank crash.

 

[Pife]

I would be worried about running the rodi as your ato. If the float valve fails you could be asking for a flood. Also when you start your rodi up you should always discard the first couple of gallons or back flush the system.

 

[josh26757]

In the event of a power failure it will! I just think using any copper-based metal in or around a reef tank is a bad idea. I'd definitely go plastic if it were me. The other thing I'd worry about is a actuator that is being held semi-permanently in a powered state. Not sure how long such an actuator would last, but I'd be inspecting it regularly.

BTW, using a direct plumbed RO/DI system for ATO is not something I would do. Runaway ATO is right there with a stuck heater for #1 reason for a tank crash.

I doubt the water would contact the valve then come back up the pvc pipe, but it is always possible I guess. Just to be sure I ordered stainless ones to be safe. I am using a float for the RO/DI and they have never failed before, should I still be concerned? I mean, my toilet has never failed and it is the same concept right?

I didn't know you were suppose to discard the first bit of water either. I have been using this for over a year with no problems thus far, but that does not mean failure is not possible. I ordered a flow meter for the ro/di along with a stainless 1/4 valve as well. I will control the ro/di with that and can even flush with a second one if needed. Just more work for the Arduino lol.

 

[josh26757]

I would be worried about running the rodi as your ato. If the float valve fails you could be asking for a flood. Also when you start your rodi up you should always discard the first couple of gallons or back flush the system.

Actually a flood is no problem as I took care of that with a drain in the floor in the basement; however, the change in salinity is a problem. I have ordered a flow meter and valve to address this. Thanks for the suggestion and help

 

[joopie]

You can use this... http://www.adafruit.com/products/997 or http://www.wicvalve.com/1-2-Anti-Co...t-Salt-Water-Solenoid-Valve-NC-2PCZ-1-2-D.htm
very cheap and 12v(i like to use a computer power supply)
I have my drain line coming off my return manifold with a N/C solenoid.. i have an arduino that i control everything through my website(see http://www.reefcentral.com/forums/showthread.php?t=2347695). I just switch "water change" to on and a relay will allow 12v to the solenoid, the return pump for my setup has plenty of pressure to push the water outside. When the sump gets around 6 inches it will switch the relay removing 12v from the solenoid closing it,then a pump will kick on and fill the sump back up to 12 inches.ATO is disabled while all this is happening.

 

[ca1ore]

I doubt the water would contact the valve then come back up the pvc pipe, but it is always possible I guess. Just to be sure I ordered stainless ones to be safe. I am using a float for the RO/DI and they have never failed before, should I still be concerned? I mean, my toilet has never failed and it is the same concept right?

I didn't know you were suppose to discard the first bit of water either. I have been using this for over a year with no problems thus far, but that does not mean failure is not possible. I ordered a flow meter for the ro/di along with a stainless 1/4 valve as well. I will control the ro/di with that and can even flush with a second one if needed. Just more work for the Arduino lol.

If I were going to run my ATO directly from the RO/DI, I would have redundant switches. So, a NC solenoid as well as the float. I've had the floats fail FWIW. Also, I've read that one should discard the first few gallons after replacing the RO/DI filters, but not after that. I don't!

 

[josh26757]

You can use this... http://www.adafruit.com/products/997 or http://www.wicvalve.com/1-2-Anti-Co...t-Salt-Water-Solenoid-Valve-NC-2PCZ-1-2-D.htm
very cheap and 12v(i like to use a computer power supply)
I have my drain line coming off my return manifold with a N/C solenoid.. i have an arduino that i control everything through my website(see http://www.reefcentral.com/forums/showthread.php?t=2347695). I just switch "water change" to on and a relay will allow 12v to the solenoid, the return pump for my setup has plenty of pressure to push the water outside. When the sump gets around 6 inches it will switch the relay removing 12v from the solenoid closing it,then a pump will kick on and fill the sump back up to 12 inches.ATO is disabled while all this is happening.

I will be looking into this now. I will also be checking out your thread. I have decided that I must implement a QT tank and this is the time to do it. I will have an overflow on the QT that drains outside. The QT will be filled with the drain water from the sump. I will not use float valves (only thing that has ever failed on me), but will take the advice of redundancy and implement double solenoids.

This is all great advice and with everyone's input I should be able to put together a sound project. Again, I thank you all for taking your time to offer suggestions.

 

[josh26757]

Not sure how long such an actuator would last, but I'd be inspecting it regularly.

BTW, using a direct plumbed RO/DI system for ATO is not something I would do. Runaway ATO is right there with a stuck heater for #1 reason for a tank crash.

We actually use such an actuator at work that is powered 24/7 as a heat exchanger bypass and they have never been replaced (17 years), but they are really expensive.

You provided a great point with regards to the RO/DI being a huge risk and I will be addressing that with redundancy. Thanks for the suggestions and your time.

 

[josh26757]

Design Update

 

[kenman345]

I am very interested in this myself. I am setting up a 56G tank without a sump but was thinking about a motorized drop PVC pipe to the tank that will have a T-split at the right level for the amount of water I wanna take out. Then use another pump and secondary ATO to fill it back up to the right amount.