DOS Manual Set Up and Siphon Risk

[SigmaVX]

I have two DOS and a DDR I was looking to hook up. I wanted to set the DOS for manual changes and the other for A/B solutions from the DDR.


The tank is a 32 Gallon Fluval Flex, which means it has a lid and a small back chamber for access during water changes, etc.

I had a couple questions:

1) The way these tanks are set up the water line sits only about an inch below the rim/lid of the tank - that is the height needed to have the in tank media baskets flow work properly. Can the water lines to/from the tank that come from/to the DOS units be submerged below the water line? Is there a siphon risk? If so how can I add a failsafe?

2) Are there any tips/considerations for how I should set up manual water changes? I plan to have the DOS flow into the tank above it (about 2-3 feet vertical height) and to/from some 5 gallon jerrycans that would be below the DOS.

 

[schuby]

There is no siphon-risk because DOS head is never open. It can push or pull liquid in either direction.

I use 2 DOS exactly as you've described. I'm setup for AWC with 5-gallon plastic jugs.

 

[SigmaVX]

Thank you. I read they can fail from time to time so that was my concern.

 

[schuby]

I think I need to expand my answer. The DOS head will never allow a siphon, but loose or disconnected tubing can definitely allow a siphon to form. Any un-glued, slip-connections carry a risk of a leak, such as on dosers, AWC, and ATO.

Some people add leak/water sensors on the floor (bottom of sump) to detect water and turn things off. I don't have any, but I do check my connections every week or two and I do a quick look-over of my sump every day during feeding time.