I almost woke up to a flood

[Leroy]

Yeah it came close to waking up to my refugium overflowing. Seems my auto top off system thats been working fine for 6 months and now has decided to keep filling past past my float switch and stops pumping water when it get to the second float switch which is the overflow switch. I'm inclined to believe the relay has gone faulty on the setup. I know what's first on my "to do" list for Monday on my tank and track down where the problem is. You really have to be on your toes to check everything, keep an eye open and an ear. I can hear my MJ pump sucking air in the ATO 3 rooms away but yet when the home phone rings I think nothing of it. I answer my cell, only rings when my arm is in the tank.

 

[swreef103]

my ultralife switch failed the first 1 hour after putting it in..after that i never keep starfish in the sump...

 

[Leroy]

My float switches are enclosed in a prescription bottles with holes drilled and secured to prevent an unwanted snail or any unwanted critters setting off the ATO MJ for unwanted top off water. The script bottles and float switches are removed and cleaned on a yearly maintenance or less depending on condition. But still keep alert on everything.

 

[reefsmurf]

float switch + drip ATO + timer = less chance of accident

 

[Jim Tansey]

float switch + drip ATO + timer = less chance of accident

Thats how mine is setup feeding a kalk stirrer, I never say never but constructed like this the chances of a flood are almost nill.

Jim

 

[dedfish]

I'll third this! I have a double float switch top-off but it still only comes on twice a day for less than 15mins at a time. I use an aqualifter that pumps from a 20g brute in the closet next to my tank into my sump. I also have a water alarm inside my stand next to my sump just is case.

I'm glad to hear you caught that in time.

 

[Dragon2115]

Did you have a diode across the coil leads to protect against back EMF? If not then you may have burned out the contacts in the float switch.

 

[dedfish]

Did you have a diode across the coil leads to protect against back EMF? If not then you may have burned out the contacts in the float switch.

Could you please explain this a bit more?

 

[Chuck Spyropulos]

Another Option

Another option, that I use, is to design the ATO system with as small of a FW vessel as possible. I use a small (<10 gallon) container with a mechanical Kent Float Valve as my fresh water holding vessel. When the level of the holding vessel gets low, the RODI unit switches on via the RODI pressure solenoid and float valve in the holding vessel. From there, I have a Reef Filler pump connected to an electronic float switch in my sump. When the sump level drops, the Reef Filler pumps FW from the FW holding vessel to the sump.

If the electronic float switch in the sump failed (shorted) then I could possibly get all 10 gallons of fresh water pumped into my sump. But 10 gallons is a small fraction of my total system volume (500 gallons) and won't significantly lower the salinity. The other thing is that the Reef Filler is a peristalic pump so there is less of a chance of the pump "burning out" from running dry. Even though the FW holding tank will continue to be refilled, it will be a slow process since the flow from the RODI is very slow. Hopefully, this gives me enough time to figure out something is wrong with the ATO. I always ask tank sitters to check the float in the sump and also to inspect the water level to providfe further safety margin when I am away from the tank for long periods of time.

One more thing is that I have had failures in the electronic level switch in my sump, but they have always been open cuircuit failures which causes the ATO to stop adding water. I found that SW or humidity was getting into the level switch relay/controller so I now place it in a plastic bag with an elastic to keep it dry. No problems for the last 3-4 years.

 

[Jim Tansey]

Good advice Chuck, but it seems that any well designed level switch should be impervious to SW or humidity. I use an industrial quality level switch, which maybe price wise, is out of the hobby range, but you will never have a problem with them.

Jim

 

[Dragon2115]

Could you please explain this a bit more?

This applies to DC activated relays. When the coil of the relay is de-energized by the float switch opening the collapsing magnetic field induces a voltage into the windings of the coil which are of the opposite polarity from the normal circuit polarity. This pulse is going to try and get to the opposite end of the coil thus completing the circuit. Unfortunately the open float switch is in the way. The Back EMF pulse can be quite high in comparison to the normal operating voltage of the circuit and over time it can damage control circuitry like the contacts inside the float switch. A way to prevent this damage is to install a diode across the coil so that when normal voltage is applied the diode is off and current only flows through the coil of the relay. When the coil is de-energized the Back EMF will be shunted through the diode and back to the coil.

Hope this helps.

 

[ReeferMedic]

Good advice Chuck, but it seems that any well designed level switch should be impervious to SW or humidity. I use an industrial quality level switch, which maybe price wise, is out of the hobby range, but you will never have a problem with them.

Jim

Do you have a link to the one you use Jim? I currently use a peristalstic pump on a timer but need a decent float awitch to prevent over flowing the ro/kalk container when I forget to turn off the ro.