I am not new to pumps, but am new to the Mobi. I keep getting bubbles in the cartridge after change is complete. I admit it is the most challenging to fill I have ever experienced. I do the fill slowly, and work the bubbles out as I go. Later I discover a bubble. Apparently air gets into the cartridge when it is disconnected. I am experimenting with unscrewing the cannula rather than removing the clip.
If you have resolved this issue I am interested in learning how. Thank you so much.
Assuming you mean unscrewing the tubing (the cannula is inside your body, I think) that sounds like a way to introduce air into the tubing…and why do it?
Don’t know how you’d get air in the cartridge. You’re sure it’s air, not just a reflection in the mobi’s transparent cartridges?
I don’t think air gets in later. I think it’s just the little champagne bubbles settling out. The cartridge is also difficult to flick to move any bubbles. I haven’t personally seen this issue, but admittedly I’m OCD about stuff like this, and I know others have reported similar issues.
Some of the things I do to avoid the bubbles:
You were getting bubbles in the tslim too you just couldn’t see them.
I agree using room temp insulin helps. Also make sure you inject air into the insulin vial then draw up the insulin. And push half back and draw it again. If I’m using long tubing I will then push through the tubing to fill it manually then I re fill the syringe. This way you can start with a full cartridge. I use only 150 in 3 days but I like to have extra.
If you hold the cartridge up while you fill the tubing, the tiny bubbles will be pushed out.
You could also try filling the cartridge and leaving it sit for a day before using it. Knock off bubbles before starting it. Those tiny bubbles will come together and this way you avoid the issue.
And lastly, I wear my mobi on my skin using double sided wig tape. I keep it so any air bubble would be trapped at the back end and won’t even find its way into the tubing. I know most people don’t wear it like this, but it works nicely for me. When my 3 days are up, I still have some insulin in there so no way would I be pushing that bubble through.
Thank you for that response. I woke up in the middle of the night last night with my BS headed to 400. I know when I put the cartridge in service there were no bubbles. The only answer is; does air get in when I disconnect? The bubble was so large, there is no way I could have missed it when it was installed. The bubble came after the fact.
I do everything you suggested in your first paragraph. I will try what your second paragraph recommends.
I tried to find a double sided tape to use with my Mobi. I will try wig tape. I do not like the sleeve, too big and too thick. Would you tell me which one you use?
Thank you.
I normally unclip the connector at the infusion set before taking shower. I notice that one reasonable size bubble in the cartridge in one occasion for unknown reason. I just place the tube on top of the cartridge, ensure the bubble at the tube entrance, press the pump button to push the bubble out (follow instructions to change cartridge, then fill tube). It worked. From then on, I always inspect the cartridge and tube system for any sign of bubble and pump them out before reconnecting to the infusion set.
It is difficult for ambient air entering the needle tip at the clip when the tube is liquid (insulin) filled. The bubble is most likely generated from heat absorbed by the liquid.
FYI, this is a common issue. Tandem instructions here:
I am also on mobi, and I know what you mean. I am using it with Fiasp, and after filling a new cartridge, I remove all the bubble and after a day or so I see the following. I don’t think it is the pump getting any air in it, rather it may be due to the dissolved air within the insulin during the filling and as the insulin temperature gets warmer, the air just separates and becomes visible. The best way to avoid the bubble (this is what I do), is to use the pump upside down, so the bubble never gets into the infusion(bubble remains on top always) and I change my cannula (infusion set) every day or every two days latest (trusteel cannula). By doing so, I have the chance to get rid of the bubble at the next change of infusion set.
I also never fill the whole cartridge, I only fill 100 units (half of the cartridge) and refill it after 2-3 days again (I am using each cartridge twice)
This method allows me to use the insulin at its max potency (in FL weather is warm) and bubble problem is also resolved.
I am using the adhesive sleeve and thats the best way of using the mobi. It is a pump that is fully controlled from the phone, I do not need to interact with the pump, so it is better to keep it safe under clothing. The adhesive sleeve cause rash on my skin beyond 3 days, I use them 10 days (replace them along with the dexcom replacement every 10 days). To prevent the rashes, the 3M spray works great. And to make sure it does not come off easy, I use Skin grip omnipod 5 patches (they fit the mobi adhesive sleeve).
This makes sense to me as you can put the sleeve somewhere that has good communication with the Dexcom.
Do you have any tips for the tubing? I’ve used the short 5” tubing but then you pretty much have to use a new sleeve each time you rotate sites. I don’t have huge problems with longer tubing getting caught on stuff but it seems like one of the advantages of how incredibly small the Mobi is would be to feel a little less tethered to a pump. I wonder if there’s an elegant solution for keeping the tubing out of the way? Do you tuck some into the sleeve itself?
I am unable to use the 5’’ tubing as those short infusion sets are not available in TRUSTEEL cannula. I can not use any other type of cannula if the needle is not STEEL. I have tried and faced many occlusions and I hate that. Since my tubing is the shortest TRUSTEEL infusion set (23" and 6mm) I do not have much of site rotation problems.
I place the DEXCOM G7 cgm back of my arm and the mobi adhesive sleeve is under the arm on the side of my body nearby the cgm. And the cannula is usually on the same side somewhere , either on the lower side of abdomen (above the belt line), or on abdomen.
By doing so I can sleep on my other side, and the next time, everything goes to the other side, and I switch side to sleep. For me it works. No issues.
About the tubing, The trusteel has two adhesive parts. And usually the tubing just stays under my undershirt without anything else. It doesnt need to be placed in a special way. The tubing is not heavy, and it usually stays on your upper abdomen area, under the under shirt, without any issues.
Thanks so much for your description. It’s so useful knowing the ways people get stuff to work. I was side to side on the arms with my Dexcom until direct to watch came out and, in my experience, that added feature only really works with the sensor on the abdomen.
I’m a frequent T-steel user but switch it up with plastic cannulas from time to time.
I might have missed it. Are you on Mobi? Because Mobi only works with the phone. There is emergency button on the pump to bolus, in case you lose your phone (I never used it). It means you need your phone all the time with you in order to interact with the pump, to bolus, change exercise mode etc.
Direct to watch is a nice function, however I do not use it (I have garmin, it requires data connection to display the BG on my watch (MARQ) Maybe one day they will also have direct to watch, but even then I need the phone all the time with me.
I’m on mobi. Direct to watch allows me to see my BG when I’m detached from the pump in the water or when I’ve just left my phone in another room. It’s not that frequent, but it’s cool. Most of the time, though, you’re right that I have my phone on me as it is indeed the only meaningful control you can have over the Mobi. Not my favorite feature, but obviously the key to the pump’s small size and weight.
Does the bluetooth work underwater also? I mean if your cgm and watch is submerged, does it still display the reading? But then again, readings are only every 5 minutes, to see the reading under the water, you need to be scuba diving 
and it shouldnt work, if you would try. Most likely it works only when your cgm and watch are both above the water. It is still nice of course 
Exactly. I know which minute I’ll get a reading and when I want a reading I stand in the shallows (or on a paddleboard ) and wait for a reading. It’s all a little dorky but an improvement over having to get out of the water entirely and stand with my phone.
