Auto Top-Off

[Jamie]

Hi everyone,

I'm going away for a week tomorrow and I'm setting up my auto top-off today. To be on the safe side, regarding an available water supply, I'm going to use my water mixing trash barrel to be my reservoir. I was thinking though...couldn't the auto top-off create a syphon and subsequently flood my sump? I am going to put the outlet a little higher than the inlet to hopefully prevent this from happening...but shouldn't there be a syphon break just in case? If so, how would I make a syphon break?

Thanks for any input.
R, Jamie

[demodiki]

I got my top off today and hooked up. Very fast delivery.

[caferacermike]

That is a very good question, especially because you might not find yourself in this situation.

Would it be possible to add your make up water to the display tank? That way the water will then fall back through the system plumbing to the sump. Using a clip of some sort you could even keep the tubing out of the overflow so that there is an air gap, no chance of back siphon.

[Jamie]

Well my fear came to fruition. I set up the auto top-off and tested it out yesterday....got it from auto top-off.com and must say that I'm very happy with it. But back to the point...late last night while I was preparing for my trip, I thought...hmmmmm...I think I should add another 10 gallons to the trash barrel just to be safe. Well, obviously I'm a knuckle head because I added the water and went straight to bed. This morning I wake up early to get ready for my flight and first thing I do is go check the sump to make sure to ATO is working. Well, I find a completely full sump...not over flowing, but pretty darn close. Apparently, when I added the water to the trash barrel, it raised the water level up enough to make its water level higher than the outlet of the tube running the top-off water to my sump. It created a syphon until it equalized. I ended up dumping about 8 gallons of RO into my sump. I have an in sump skimmer...it was going crazy. Luckily I just cleaned it yesterday afternoon...so a bunch of gunk didn't get mixed back into the tank. I'm hoping the SG swing doesn't agitate the inhabitants too much....so far so good. I ended up pulling the excess water from the sump and putting it into my top-off reservoir...so I'll be adding to the salinity very gradually.

My flight ended up getting delayed 7 hours...so I'm back home now checking on things. Stressful morning though.

[longhorna95]

when I put in my auto-top off i put the return line into my overflow, that way when it puts in fresh water it goes through my sump/refuge and get everything I need for my tank, it also helps prevents accidents like yours. LFS info helped me out a lot on this!

[bronck83]

Thanks for posting this, this potential problem never occurred to me for some reason.

[ErikH]

I have my 5 gallon bucket underneath my tank. The hose from the maxijet goes up into the display and is zip tied to the return line, just above the water.

[apedroza]

It is always a good idea to have the level of the water lower than the sump so siphons don't get created. My water level is just below the outlet for the return to the sump. I also have a long enough hose to creat a drip loop of sorts so the water has to be pushed up in order to fill into the sump.

[Texreefer]

I would add.. try never to make changes like that right before taking a trip.. that could have happened while you were gone

[coraline79]

I second that. don't make any changes before leaving town.

[RayAllen]

Yikes, glad you caught it. When I installed my auto topoff I was able to keep a close eye on it for a couple of days and noticed that it was syphoning on its own. I quickly realized that if the tube was pointing down when the pump turned on that it would simply continue to syphon when the pump turned off because when it stopped air was not able to get into the tube. I simply ziptied the tube so that it pointed up and this made it so a air bubble shot up the tube and stopped the flow; I never had the syphon problem again. And my water level in the resivoir was higher than that of the sump with no problems at all.

[rocketeer]

I have my topoff system flowing through a float valve as a last resort safety. If everything else fails in an "on" mode, the sump fills another inch or two and the float valve closes.

Jack

[longhorna95]

I agree, you should never attempt to make any changes to your tank i you cannot be there for the next 24 hours to make sure a seal, zip tie etc. will stay in place and that your changes actually work.

[matt]

This is exactly what I like about my top off system, which is a dosing pump pushing water through a kalk reactor. There is literally no way the dosing pump can continuously add water like a float switch/powerhead arrangement. I do have to periodically adjust the output of the dosing pump to match seasonal changes in evaporation, but that's a small price to pay for never worrying about the system sticking on and flooding the sump.