Bubbles in Dosing Pump Tubes?

[SPR]

I have just set up a 4 channel Kamoer dosing pump and am using TMC dosing containers (the ones with the round hole in the top with a blue lid).

When I prime the tubes there are no bubbles and the liquid flows through fine. However over the period of a few days I start to see air pockets in the tubing.

The dosing containers are sealed and the tubing is all submerged, but I'm not sure if they are actually air tight as such and creating a vacuum so this morning I have taken the lids of slightly to see if by letting air in this helps. Am i supposed to create a vacuum or should I let air in ?

The end of the tubes in the tank (above water) have non return valves fitted.

Any thoughts greatly appreciated..

 

[DaveK]

This sometime occurs, and it can be for several reasons. This may or may not be a problem depending upon several factors.

How large are the bubbles? small ones will just pass through.
Are they before or after the dosing pump? As long as there is not a leak, bubbles after the pump are not an issue.
Are you still getting proper dosing? If you are, the bubbles are not an issue.

Generally, you don't want the dosing supply containers to be air tight. A very small hole in the lid or near the top of the bottle is all you need.

Of course, check your connections. It's real easy to have some that are leaking.

 

[SPR]

This sometime occurs, and it can be for several reasons. This may or may not be a problem depending upon several factors.

How large are the bubbles? small ones will just pass through.
Are they before or after the dosing pump? As long as there is not a leak, bubbles after the pump are not an issue.
Are you still getting proper dosing? If you are, the bubbles are not an issue.

Generally, you don't want the dosing supply containers to be air tight. A very small hole in the lid or near the top of the bottle is all you need.

Of course, check your connections. It's real easy to have some that are leaking.

Thanks Dave

The system is dosing and bubbles just pass through the system but the reason for the query was that i have calibrated the pumps when filled manually with the doser so no air bubbles. When i then leave it over a few days a few bubbles appear and I'm just concerned this will reduce the amount dosed. I suppose its slightly better to be under dosing rather than having to much and I again assume the difference may not be that much anyway so maybe I'm being a bit over the top with this. I just like things to work correctly so to speak.

The bubbles seem to be before the doser at the liquid end - i have had the lids on tight so will try with a small gap in the tops and see if they disappear like you suggest.

I have the NoPox set up as well which seems to be ok as that has an air tight lid and non return valve to avoid evaporation so I just assumed the Ca Alk Mg should also be airtight. The non return valve on this however does let air in to avoid the vacuum.