Water on the floor - need level switch for refugium pump

[siege]

So, I've got a check valve on the line to my fuge to prevent reverse-siphon (plus the return pipe outlet itself is just above water level).

BUT, while getting everything up and running the other night, I got called to walk the dog. Everything seemed to be working fine, so I stepped away...

and came back to water pouring off the top of the fuge and into my carpet.

Fortunately, it seemed to have just started by the time I came back to my office and it wasn't a whole boatload worth. Seemed the siphon hadn't started properly yet.

So, I need a mechanism to cut off my fuge pump (a cheap AquaNeat 160gph) when the water level gets too high.

I'd consider using the optical sensor made for my Apex, but the reviews on those are awful and say they fail without warning, typically within a year or two at most. They're not expensive, per se, but as someone who used to work in industrial liquid level measurement and gauging in some of the nastiest environments/liquids imaginable, I can say with some authority that a simple optical sensor in something as tame (by comparison) as saltwater should last MANY years with only the most basic care and maintenance.

So, I'm looking for a cost effective alternative. It doesn't have to play with my Apex at all, I just want something as a failsafe. I'd like something like the RODI Flood Guardian from XP Aqua, but it uses a solenoid meant for John Guest tubing, which is far too restrictive for my fuge pump (even dialed back to about ~40gph as I have it).

I'd like something like this, this, this or this, but none of them seem to be at all appropriate for marine use, with metal contact sensors that will inevitably corrode just hanging out 1/2" above the water level.

Hoping someone here might have a suggestion? Or should I just bite the bullet, spend the money on a pair of the optical sensors for the Apex (at $30) so I can have one as a backup, try sealing the ends of the cable with silicone, and plan on doing a regular maintenance check on it?

 

[project1004]

You robalybcan get this done using Apec breakout box with fiat switches to automate the pump to on and off. Also use them to turn your sump lights on and off when opening etc.

Or you can get one of these floor water detector everyone seems to use as manual way to be warn. I actually have both optical sensor and WLD (water leak detector) by Aprx but Havnt put me on yet.

 

[chaples55]

You can also just raise your fuge return pump so that it runs dry before the tank overflows

 

[chaples55]

There's also this option: https://www.bulkreefsupply.com/smart-skimmer-security.html

 

[siege]

There's also this option: https://www.bulkreefsupply.com/smart-skimmer-security.html

AHAH, that is exactly what I need!

The issue here with trying to elevate the fuge return pump is the setup with the fuge as a display tank itself elevated above the main display, and the fact that I have a sump-less system with an AIO. I'd have to manage that solely through lengths of plumbing to suspend the pump just so.

Right now I'm running with about an inch of headroom between the water level and the rim of the tank. 350mm x 350mm x 25mm equals 0.81 gallons, which makes the margin of error vanishingly small.

The original issue was simply user-error, really. I'm not sure (now, a day and a half later - EDIT: it was air in a submerged line stopping the siphon from forming) why the emergency return didn't take at that point, but I'm sure it's some fault of mine, and that now everything is good to go. I've got my valves all dialed in, and the amount of flow is enough that the water level in the overflow stays down near the bottom but inflow is just enough to keep full siphon on the primary return, and the emergency drain is definitely working.

Still, the entire family went out last night to celebrate my oldest son's birthday, and half the time we were there I was wishing I had put a camera in my office on the tank before we left just so I could check in on the level in the 'fuge, and I'm a bit paranoid now that something could fail in the event of a brief power outage, or when I have to go out of town for work (which I have to do in a few weeks) and have someone else looking after the tank for me. Having a way to ensure the pump cuts out before it can overflow would bring a huge amount of peace of mind.

 

[siege]

I literally just jumped out of my chair at the sound of the water splashing into the filter to see what was going wrong with the fuge and why so much water was running through the emergency drain to make that much noise.

It was the ATO

I definitely gotta get one of those things before I go out of town.

Also realized the actual solution to the problem is the continuous piping from the primary return line from the fuge into the AIO filter section dropping straight into the water. When the siphon breaks, the line fills with air, and then doesn't re-start. I either need the return line end suspended above the water line of the pump section of the filter, or I need to put a hole in it for a reverse siphon-break

 

[siege]

Tried a few things - so far, the best option seems to have been to cut the tubing so it hangs just above the normal level in the filter. I tried a 90º elbow, as well as a Tee but they were all somewhat problematic and inconsistent, or noisy.

This works for now, but definitely going to need to find/engineer a better long-term solution.

One thing to note for posterity and anyone else doing anything similar: I had to use my Apex to configure the ATO to turn off any time the fuge pump turns off, and set up a 10m delay timer before it turns back on again in order to ensure everything is stabilized. The issue was the fuge pump draining the pump chamber (where the ATO sensor is) and the lag before water starts flowing back into the same chamber.

Realistically, 5m was enough in testing, but having the ATO turned off for a few more minutes certainly isn't going to hurt anything, and I decided to err on the side of caution.

 

[chaples55]

Ah yes I've experienced that "air lock" problem preventing a siphon from starting when the end of the drain is submerged. The smaller the diameter of the tubing and the lower the head pressure the more likely it is to happen. If I recall correctly, you have very little height difference between the filter and the fuge, so almost no head pressure. Solutions that have worked for me in the past were:

1. 90° elbow on the end of the drain, dipped halfway into the water line in the sump.
2. Drain onto a coarse sponge just sticking out above the water line. This is basically the same as draining straight into the sump (above the water line), it just gets rid of the splashing sound associated with that.

 

[siege]

Ah yes I've experienced that "air lock" problem preventing a siphon from starting when the end of the drain is submerged. The smaller the diameter of the tubing and the lower the head pressure the more likely it is to happen. If I recall correctly, you have very little height difference between the filter and the fuge, so almost no head pressure. Solutions that have worked for me in the past were:

1. 90° elbow on the end of the drain, dipped halfway into the water line in the sump.
2. Drain onto a coarse sponge just sticking out above the water line. This is basically the same as draining straight into the sump (above the water line), it just gets rid of the splashing sound associated with that.

So with the way everything is currently arranged/fallen-into-place, the end of the line is just above the water level, but not making any splashing sounds. However, I've got plenty of coarse sponge and will give that a go if need be. I'd have to pull some water from the system to lower the level in the return chamber so I could use the 90º elbow I have without it being under the water level. I might be running it higher than strictly necessary, but too much lower and my overflows to the filter socks in the display tank gurgle.