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Dosing Pump tube replacement


cmrun

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I have attempted to replace the tubes on my Bubble Magus dosing pump. (T-11) The motors still turn their stainless shafts but the roller assemblies no longer turn pumping the liquids into my sump. I took apart each head looking to see if I had somehow changed the configuration (or other set up error) and have not identified anything. When I remove the tubes and re-assemble the heads I can see the roller assemblies are turning. (BM replacement tubing used... is there maybe a difference between tube kits from the T01 and T11?)

Any suggestions for trouble shooting? Hate to spend $75 for new heads when really all that it should need is new tubes.....🙄

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Personally, I think the new tubes are on the high end of the tolerance range. Extruded rubber tube has a wide band of acceptable finished product dimensions because there are so many factors with production. The wall of the new tube itself is wider that the original tubes installed. (I am looking at the tube ends and while they are not worn could be stretched-out compared to the new tubes).

The rotating barrels or wheels seem to be much harder to rotate with my thumbs on the new tubes compared to the old tubes.  The new tubes are far more difficult to install compared to the old tubes. I put back all the old tubes and may just buy new heads... which I will return if they do not function.

Not pleased that the tubes cannot be replaced as a maintenance item (and function like they should). I my opinion,  the rollers and motor shaft should have a positive drive mechanism and not just rely on friction between the motor shaft and the roller plate and rollers to drive the unit. 

In every case the shaft will spin when the motor is turned on, but the rollers do not turn with the new tubes installed. 

Still waiting on some more info. from Seaside / Bubble Magnus but they have not provided any useful information to date.

{Buy the way, I have been involved with the rubber and other types of seal components used in the sealing industry for the past 31 years. My comments on tolerance bands is not just an opinion. I have worked on,  engineered, and design seals used on cruise ship propulsion systems, US Navy radar turret seals, trouble shooting problems on pumps used in nuclear power plants, and many other basic or critical applications in industry. So, not being able to properly service a little "hose pump" is a bit frustrating... also keeps my ego in check, lol!}

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  • 2 months later...

Just stumbled upon this thread. Sorry for the late reply.

I’m starting to think there’s a single, large manufacturer of latex tubing in China that is having some major quality escapes that are affecting a large swath of end users. I just had a brand new Jebao dosing pump do everything it could to wipe out my tank. Three of the four pumps displayed the same behavior: they would intermittently allow the contents of the dosing containers to siphon into my sump. Completely random. It appears there was a section of tubing that was thin-walled, and when the roller stopped on a thin-walled section of tube, it wouldn’t seal and the jug of vinegar, magnesium and/or 2-part would drain into the tank.

(Three cheers for the 50 gallon barrels of warm DI in the garage! I’ve added “have the ability to do a 50% water change in <2 hours” to my list of reef keeping rules to live by.)

I’ve since replaced the Jebao with a BM T11 that has been working flawlessly for the last week. Do you suppose some silicone lubricant in the roller assembly would be beneficial?

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