Float valve question

Hijinks_78 · Dec 18, 2019

On my last system I built an ato that uses a gravity and a float valve above my sump. This has worked out really well and I like it a lot more than any of the other ato systems I’ve had in the past that inevitably had issues at some point. In my new build I planned on building the same type system but ordered a different float valve. It was labeled for aquarium use. The Other float valve I used was completely plastic, but this new one has a stainless screw connecting the float. It will inevitably get salt water on it. How much would this worry you guys? Would you get a different float valve that is all plastic ( this one is smaller and space is at a premium which is why I selected it, but there is enough space if needed to use the larger all plastic one).
One other question. Is there a reason I have not yet found that more people do not use this style ato? With out a pump it just seems so much more reliable...is it simply a space issue and the fact that the ato reservoir needs to be above where the water enters the tank or is there an issue I just am not seeing. I almost never see anyone use this style and it just seems so simple and effective...

CuzzA · Dec 18, 2019

It is fine for smaller ATO reservoirs, but if you have a large reservoir a valve can still fail and consequently dump a lot of fresh water into a tank. This would be even more problematic if your reservoir is setup to auto refill. Also, for gravity systems, you need height, which is something most people don't have in a stand.

The stainless steel will eventually rust. If it is true marine 316 steel it would take a very long time and I wouldn't be concerned. Just keep an eye on it or see if you can replace the steel parts for plastic.

George Lopez · Dec 18, 2019

Ilove my gravity feed ATOs. Both of mine have a stainless screw and never did anything. They are both shiny and new years later.

jomatty · Dec 18, 2019

CuzzA said:
It is fine for smaller ATO reservoirs, but if you have a large reservoir a valve can still fail and consequently dump a lot of fresh water into a tank. This would be even more problematic if your reservoir is setup to auto refill. Also, for gravity systems, you need height, which is something most people don't have in a stand.

The stainless steel will eventually rust. If it is true marine 316 steel it would take a very long time and I wouldn't be concerned. Just keep an eye on it or see if you can replace the steel parts for plastic.

I suppose it could fail completely but it seems more likely that it would be more of a gradual breaking down that would have some warning signs before dumping the entire reservoir. I could be wrong about that though. I guess it just seems less likely to fail then systems that require sensors and pubs even if they have double sensors. I just hear about so many people having issues with theI could be wrong about that though. I guess it just seems less likely to fail then systems that require sensors and pumps even if they have double sensors. Stand height is definitely an issue for a lot of people though. It makes it tighter than I would like it for sure...

mike550 · Dec 18, 2019

@Hijinks_78 if the gravity fed ATO / float valve works for you I’d keep going with it. On the SS question I’d just keep an eye on it or simply plan to replace it once a year or something as part of a maintenance cycle.

You could probably repurpose the “old” one to your RODI or something.

CuzzA · Dec 18, 2019

jomatty said:
I suppose it could fail completely but it seems more likely that it would be more of a gradual breaking down that would have some warning signs before dumping the entire reservoir. I could be wrong about that though. I guess it just seems less likely to fail then systems that require sensors and pubs even if they have double sensors. I just hear about so many people having issues with theI could be wrong about that though. I guess it just seems less likely to fail then systems that require sensors and pumps even if they have double sensors. Stand height is definitely an issue for a lot of people though. It makes it tighter than I would like it for sure...

A valve failure would be from some serious neglect or poor system design. What happens is since RODI water is free from any disinfectant, bacteria can begin to accumulate at the valve opening and lead to a failure. Also, if you have sump critters, like a refugium with snails, they could prevent the valve from closing. If you drip kalk through your ATO the buildup can certainly lead to valve failure. Finally, I've read of some failures from leaks in the float which fill with water and of course no longer close the valve.

On my last system I ran a gravity ATO and you can't get more precise than a gravity fed system. A little forethought and maintenance every so often removes the likelihood of failure.

Feet4Fish · Dec 18, 2019

I run a gravity fed ATO as well with a float valve and the have a secondary solenoid valve with optically eye mounted higher for redundancy. Thhe float valve you have should work fine, but like the others said just periodically monitor the screw for compromise. The precision of a gravity fed system is unparalleled. One should take appropriate considerations to avoid catastrophic failure. For me I have two layers of redundancy and even if the entire contents of the ato dumped into my system it would have a negligible effect on my salinity.