DIY ATO With Peace of Mind and Fail-Safe?

[pezenfuego]

I have been thinking about ATO and how devastating it can be when they fail. So then I started to wonder, what about adding three or four float valves? Of course I would never do this to my tank, but in a very large aquarium with a very large reserve, this would be a fantastic idea. That way if one float valve failed, the entire thing would shut off preventing a flood or a hyposaline tank. Of course, if one valve malfunctioned, the entire thing would stop working and the ATO would become essentially useless. So it would need to be wired in such a way that 2/3 or 3/4 of the float valves activating will turn on the pump.
But why stop there? If a float valve is malfunctioning, you should know about it, right? So then the question became, can an indicator light be added to indicate when the valves disagree? Since I have insomnia tonight, I decided to draw up the simplest circuits (using boolean algebra).
I figured all of these questions out, except for the very basic question, how do float valves work and how can they be added to a circuit?
All of this is very hypothetical and meant to further my own understanding of float valves and how they work. In the unlikely scenario that somebody wants to do this, I would be more than happy to share my circuit diagrams.

 

[beaslbob]

sounds like you're on the right track.
Some float valves are mechanical switches while others are inductively triggered.
One very huge safety consideration is to insure the switch itself run on DC to fire a remoted relay to control the ATO, pumps and so on. AC can kill especially with all the salt water around. But DC will not harm at lower votages. Which is why you can put your finger over a model train track and not get shocked.
And just as a reminder to all readers, what is really important is the basic adjustments of the system are such that floods do not occur. Relying on switches does not replace that idea.
my .02

 

[pezenfuego]

I agree entirely about not relying on switches. Thanks for the response. I thought they worked by sending a small current through the mechanism. If the switch was down, the connection would be completed. My friend gave a mechanical explanation. It sounds like we were both right. If I ever get a large tank, I will surely build something. I think it is a great idea.

 

[acrylic51]

Curious as to why or what you'd tie into a "very large system" that would dump that much water to take a system into hypo.....That in itself doesn't suggest good planning IMO.

 

[pezenfuego]

It's all relative and semantic. A large aquarium has a large reservoir relative to the reservoir of a small aquarium. Dumping the entire reservoir into a tank is no bueno. It will negatively affect the tank's salinity level. I know I didn't need to explain that to you.

 

[acrylic51]

Understood, but don't see the point in tying a large top off reservoir to any size tank......Almost like tying your RO to your sump......Heck I have a 180 gallon water vat that I'd never tie to a system.
I understand what your after, and is a very solid idea, but why use cheapo floats....Something optical, but again nothing is fail proof

 

[acrylic51]

What's wrong with the Litemeter.....Could easily hook an alarm to trigger failure

 

[pezenfuego]

The hypothetical situation was dealing with safety in numbers. Add a float valve and the likelihood of a failure is halved. It thought it was an interesting idea. That's all. As I stated, I never planned on actually doing it. I never said anything about a 180 gallon reserve for ATO.

 

[acrylic51]

Hypothetically there are products already there to minimize the issue of failures.......

 

[pezenfuego]

In reality there are products already in existence to minimize the issue of failures. This is discussion for the sake of discussion. I presented a hypothetical and received an answer. Anything else?

 

[ghostsoul]

One other redundant saftey you could use is similar to a float switch. Simply attach a magnetic switch to the lid of your tank that will break the circuit to your ato pump in the case that the water level in the tank is high enough to lift it. This would of course be the last line of defence from a catastrophic ato failure and Im sure there would be a little water spillage, but hopefully not much.

 

[fishhugger]

Just an idea, why not have a reverse float valve (I dont know if they make those, but when the valve is down the circuit is complete, when its up the circuit is incomplete) wired into your existing ATO. And have that float valve sit higher then the one that controls the water level. It seems to me that It woudl be less prone to failure then having 3 or more float valves at the same level.

 

[acrylic51]

Quote:
Originally Posted by FishHugger http:///t/393916/diy-ato-with-peace-of-mind-and-fail-safe#post_3510657
Just an idea, why not have a reverse float valve (I dont know if they make those, but when the valve is down the circuit is complete, when its up the circuit is incomplete) wired into your existing ATO. And have that float valve sit higher then the one that controls the water level. It seems to me that It woudl be less prone to failure then having 3 or more float valves at the same level.
Those valves do exist.....
Quote:
Originally Posted by ghostsoul http:///t/393916/diy-ato-with-peace-of-mind-and-fail-safe#post_3510617
One other redundant saftey you could use is similar to a float switch. Simply attach a magnetic switch to the lid of your tank that will break the circuit to your ato pump in the case that the water level in the tank is high enough to lift it. This would of course be the last line of defence from a catastrophic ato failure and Im sure there would be a little water spillage, but hopefully not much.
Honestly if the water pressure is enough to lift the lid on your tank...You have serious water issues and it's gushing by that time......Would have to be a pretty sensitive switch kept super clean as well.....

 

[ghostsoul]

Quote:
Originally Posted by acrylic51 http:///t/393916/diy-ato-with-peace-of-mind-and-fail-safe#post_3510725
Those valves do exist.....
Honestly if the water pressure is enough to lift the lid on your tank...You have serious water issues and it's gushing by that time......Would have to be a pretty sensitive switch kept super clean as well.....
We have some vessels at my chemical plant that have similar limit switches that can trigger a break in the control loop with as little as 2mm of movement. Using two pieces of aluminum foil I have knocked together a simple limit switch hooked to that old 9v battery/light bulb setup just about everyone has done as a child and it works very easily as a proof of concept. Once the aluminum lifts even a little the circuit would be broken so the pressure pushing the lid up wouldn't even have to deal with magnetic hold. Of course once the lid closes back the circuit is complete again so a relay would be needed to keep the pump from restarting. As for water gushing out of your top, yeah I agree there's problems there if a switch like what I suggest is being used, that is why I said it would really only work as the last line of defense in trying to prevent or limit a catastrophic failure, similar in use to rupture disc's or pop off safety valves, if they're being used there's serious problems somewhere.
Since this is all hypothetical I can also imagine an hang on lip around the top of the tank that would direct any overflow into a buffer vessel instead of your floor... It would look ugly as sin though.