Preventing a flood

[miles o'reef]

I'm planning the setup of a new tank and I'm trying to figure out how do I prevent the tank from overflowing if the internal overflow get clogged?
Since I plan on having an auto-topoff system in the sump, if something goes wrong with the internal overflow (like something clogging it), the display tank will overflow onto the floor.
I really don't want to add a float switch to the display because I want to keep a cleaner look.
Any suggestions?
Thanks,
Miles

 

[squidd]

Float switch on the sump...
If the water goes "up" and stays in the tank...water level in sump will go down...
Float switch shuts off return pump before MT overfills...
If you run ATO in sump, you would need way to "overide" so sump doesn't refill and kick pump back on...
Do able if you think it through... :thinking:

 

[miles o'reef]

Squidd,
That's exactly what I am trying to figure out - how to override the ATO so that the sump doesn't refill and turn the return pump on. I had already planned on installing a float switch in the pump.
Do you have an idea on how to override the ATO?
Thanks,
Miles

 

[squidd]

It's going to depend a bit on the "particulars" of your set up but I can give you some "basic" theory..
The overide is based on the "differential" of level swing between "normal" ATO, and an emergency, flood the tank "drop"...
Let's say your "normal" ATO differential is 1/2" ...
IE: Water evaporates, level drops 1/2", ATO kicks on, fills 1/2", kicks off...return pump keeps runing...
Then, say a snail clogs your overflow...
Main tank starts to fill and sump level will drop 3",4",5" like NOW...
"If" water drops "that" low float switch cuts power to return pump AND ATO...(so it won't refill sump...) All power off... No flooding tank...
The only thing to watch out for would be the "backwash" from the lines draining...
As long as the "back wash/power out level does not turn the return pump back on...
Every thing will stay off until you have a chance to clear the clog and "fire up" the system again...
"How" you do that will depend on the size/shape of your sump, the level your ATO is set, how much room you have for "backwash, etc...

 

[squidd]

Originally posted by Squidd
...As long as the "back wash/power out level does not turn the return pump back on...
Every thing will stay off until you have a chance to clear the clog and "fire up" the system again...

OK, after "pondering" on this for a bit, I realized that this scenerio will only work on the assumption that the snail "totally" blocks the overflow and excess water "stays" in the MT and sump level drops...
In reality you are more likely to only get a "partial" blockage or "slowing" of the overflow...
Assumption #2 is going to be that the blockage is still great enough to lower the sump level faster than the ATO can refill it, and again "shut the system" down, due to low level in the sump...
But in this case the water would continue to drain (although slowly), the sump would refill and the pump start running again..
Two options here...
1. Let the pump "cycle" fill, drain sump, stop, sump fills, start, sump drains,stop,etc....Probably not the best choice, hard on equipment and sooner or later the ATO will add enough water to the system to cause a flood...
2. Add a "Magnetic Switch" like the type found on Machinery....
With power to the "switch" You start the pump by energizing the magnetic solinoid...when power goes out due to low sump level, solinoid releases and even if power is restored, pump (and ATO) will not restart until you "reset" the solinoid...
That takes care of that problem...
The "next" scenerio/assumption is a little tougher...
Overflow only "slows" due to minor restriction ...Return pump pushing water up "just a little faster" than the overflow can drain...MT level slowly rises...ATO "keeps up" with falling sump level...so it never shuts off...
How do you deal with that...??? :thinking:
(retorical question, but it's your turn to answer)

 

[miles o'reef]

Squidd,
Great responses! This is exactly what I've been trying to figure out.
I like you thoughts on the float switch cutting power to the return pump and ATO if the water level gets too low in the sump. What would be really nice is if an audible beep/alarm would also sound to let me know something was wrong.
Can magnetic switches/magnetic solinoid be found at most hardware stores?
Good question on how to deal with a partially clogged/slow draining overflow. If there were some way (like a sensor) to measure the rate of drain.....
Not quite sure :notsure:
Miles

 

[squidd]

Originally posted by miles o'reef
...Can magnetic switches/magnetic solinoid be found at most hardware stores?...

Probably not, unless hey were heavy into equipment repair...
Best bet would be a "Grainger" catalog or Grainger on-line...They sell "industrial" parts, but once you find them and know what your looking for/at...you can transfer that knowalage to a lighter duty electrical tool repair shop...
It is a "common" part... and should not be difficult to find...
As far as the "slow rise" scenerio...Only thing I can come up with at present is a float switch "hidden" in an upper corner of the tank...and it would require the magnetic shut off switch for pump and ATO, because if it does shut off the pump due to a level rise...the tank level will drop due to "slow" drain and "backwash" drain..
At which point, we're back to finding a nice " unobtrusive" location for an in tank float switch, because with a Magnetic Solonoid, it would cover all three scenerio...:yes:
So how about upper left corner, in the back, and covered by a "colored" acrylic shield (to mach background)...so you cant "see" the switch...?? :thinking:
Because if you "think" about it..."switching" based on the sump level is really dealing with the "symptoms" rather than "addressing" the problem/level in the MT...