Resevoir size effect ATO siphoning?

Yes thanks FOD, I def was going to have the tube out of water basically suspended over my return area. But I'm still thinking that since that larger reservoir will be so much taller than the sump, it's still a "gravity wins" situation, no?

 

My tube is set like yours...from my 20 Gal to my Sump (basically both at the same height). My pump pumps from one to the other, and when my ATO kills power to my pump, the water ceases and stays in the tube...it doesn't continue to fall (gravity), and doesn't go back into the ATO...just sits. I am using 1/4" airline from a Tom's Aqualifter...traveling 36" tops in a straight line and then 90* fall into my return section.

 

If the water level in the res is higher than the output of the tube it can cause a siphon.

Could you use a float valve and siphon to deliver the water instead of a pump?

 

I'm not saying this is incorrect, however, mine does not act in this manner. When fully filled, my ATO Water Level in my Res is 2" above the end of the tube...no siphon exists.

 

It probably depends on the pump used. The tube on my ATO doesn't stay full. Water flows freely through the pump. It works for the time being since my ATO outlet is higher than the res level.

 

Got it, seems like yours might be a little more even than mine would be if I went with the much taller reservoir. It would basically be 10inches+ if I went with that one and I'm still worried that drop down into the sump would cause the siphon. I'm leaning now more towards the lower to the ground reservoir. I'm thinking with that one, the water level in it may be below my sump possibly or at least equal.

 

you can also run the tubing from your reservoir higher before dropping it down to your sump. water does not like to defy gravity, so it should not siphon if it has to go up 1-2 feet from your reservoir before going down to the sump.

 

Yeah I was thinking of putting a big "arc" into the tubing but I know if I got the taller reservoir it wuuld prob look a little ugly since I'd have to run it behind the tank & I don't have a background. Still leaning more towards the smaller reservoir even more now as I could do an "arc" much easier and less noticeable on that one. Only thing that stinks is that it's a wider footprint so the pump will get unsubmerged quicker than that tall skinny one.

Thanks so much for all the input everyone, maybe this will help other owners of the Tunze.

 

Interesting, I just received this from Tunze directly:

Pump up to the tank and you don't even have to worry about it. The sensors should go in the sump but the top off hose should always be routed to the tank, if you insist on pumping to the sump, the water level of the reservoir must be below the end point of the hose. My personal opinion is both are two big. Consider the reservoir volume to be the final safety, if your tank couldn't safely absorb 20+ gallons of freshwater, I wouldn't use a 20+ gallon reservoir, typically we recommend about 5-10 gallons. Just enough for 1-2 weeks.

So they're recommending pumping directly to the tank. I do agree on their "safety" of having a smaller reservoir. Maybe I should put the tubing over my overflow, how bout' that?

I didn't realize you could seperate the sensors and where the tubing goes, that's kinda cool. So, the sensors will trip when my return area goes down and then pump to the tank or the overflow. Ok, I'm starting to "get" it now.

 

That sounds like it'll work. I agree with the whole less volume as a safety factor...but like I said, if you have some EXTRA safety measures installed, then get the size you want. I know someone said that the Tunze covers all safety measures...but I wouldn't trust one safety device. I have 4 on mine.