Peristaltic pump siphon break?

[SaltLife]

I have a peristaltic pump (located under tank) doing automatic water changes for my all in one tank. The containers are below the tank and pump. In a perfect world I would have my dosing pump above the tank so that a siphon would not start. However, cosmetically this doesn't work very well for me. One tube must be submerged to take out water while the other doesn't and is above the water line putting new saltwater in. While their should never be a siphon created using these types of pumps, the possibility is there and a tank crash would probably follow. 

 

I'm crossing my fingers that there would be a solution to this, in creating some kind of siphon break without the dosing measurements getting off. The tube outside diameter is 1/4".

 

Any ideas and opinions would be greatly appreciated. Thanks. 

Edited April 29, 2016 by SaltLife

[Origami]

A good peristaltic pump should not have an open path. However, there are some cheaper, two-roller pumps that I've seen that could suffer the fate that you describe. You can avoid this sort of siphon by installing an upward-pointing open tee at the high point on the output side (which ideally should be higher than your max reservoir height). This will allow air to enter the output side and break any siphon that could form there.

[Reefer_Madness]

^^  I used Tom's suggestion and it fixed my Tunze ATO siphon problem.  It works. 

[SaltLife]

A good peristaltic pump should not have an open path. However, there are some cheaper, two-roller pumps that I've seen that could suffer the fate that you describe. You can avoid this sort of siphon by installing an upward-pointing open tee at the high point on the output side (which ideally should be higher than your max reservoir height). This will allow air to enter the output side and break any siphon that could form there.

 

Thanks for the help on this Tom. With the siphon break on the line this will not effect the dosing amount? Of course if a siphon was to occur I'm sure that it would but it would be very minimal in my case. 

 

Unfortunately the Apex DOS is a two roller system, maybe for a next time purchase a lab grade three roller will be used instead. 

[Origami]

If the pump loses prime (that is, drains back into the reservoir because the rollers are not pinching off flow) ) , then it could have an effect. In that case, you might need an inline check valve on the input side. However, the tee would have no effect on the dose on the output side.

 

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[tom39]

Which peristolic pump are you using?

[SaltLife]

I'm using an Apex DOS