Switching to Tadem t:slim

Hi all,

My current pump, a Medtronic Paradigm 751, is out of warranty and I’m seriously considering switching to the Tandem t:slim X2 pump with Control IQ and Basal IQ. I already use a Dexcom G6 sensor. I’ve used Medtronic pumps my entire life, and before I make the switch was wondering if any tslim users can weigh in on the pros and cons of the pump? Do all the pros outweigh the cons? So far I’ve seen the cons of charging, a bad pump clip, the large tubing connector and issues with loading the cartridge.



Hi Caitlin @CaitlinH, welcome back to the forum.

For me, the pros far out weighed the cons. Like youn I had used three progressively improved MiniMed paradigm pumps before changing to the Tandem t-Slim x2 January 2019; I had begun using the DexCom G5 sensor July 2018.

I have found that Control IQ [CIQ] is all as advertised and then more - since January my TIR [Time-in-Range] has been over 90%. I had begun using Basal IQ [BIQ] the previous December; note that you can not use both BIQ and CIQ at the same time - once a pump is upgraded to CIQ it can not be down-graded.

A feature I really like about the Tandem pump is its compact size and really sharp screen that I can see with my weak eyes even in bright sub-light. The CIQ algorithm improves on the limited adjustments offered in BIQ and also has the added feature of automatically infusing correction bolus’ at 60%. I suggest that you thoroughly read the User Manual [with its many pages of “warnings”] before using CIQ. For me, the decision to change was very easy.

Some users do not like the orientation of the clip on the pump case; the clip orientation can be changed - also in the User Manual. It took me a while to cet used to how I wear my Tandem; I’ve found that the Tandem fits snugly in an old holster I had gotten with my Paradigm pump.

Another “con” for many is getting used to filling the Tandem cartridge; for me, it took a few/several weeks, but now I do the job as easily as the former MiniMed reservoirs.


I switched from Medtronic to Tandem years ago and have not looked back - frankly I loved the sleeker look and more compact design of the Tandem. Several weeks ago a young lady at the mall wakes by me with her Minimed on her waistband. I cheered her on, “Wear your pump with style!” She and her friend turned around and saw my Tandem on my waistband and were intrigued. It’s been a while since I’ve seen a Minimed “in the wild” and I was surprised at how chunky it looked, but that’s just my personal opinion.
I’m pretty easygoing when it comes to change so I adjusted quite a while ago but new “transfers” do complain about the cartridge fill time.
When I get a new bottle of insulin I sit down and load a bunch at a time and store them in a Tupperware type container in my fridge - when is time to change the site I attach and do the tubing and I’m good to go.
They have a simulator app you can try to see how the functions work - it’s available for iPhone - I don’t know about Androids.
I found a couple of containers I use to carry. One is a pill box.image
The second is a Mentos metal tin. You’ll appreciate the irony that it is a candy tin😃.

Charging the battery is quick. I understand concern about power outages but I plug mine into my car charger while I’m driving, and even use a “charging brick” sometimes.


Hi @CaitlinH,

I used Medtronic pumps for over 20 years. The last 1.5 years I used a 722 to run DIY Loop, a non-FDA-approved automated insulin delivery system. Loop gave me greatly improved A1C, improved sleep, and reduced mental overload. I decided to switch to Tandem once they released the CIQ software because I wanted to get on a commercial system that had many of the capabilities of Loop. I started the Tandem system on April 9, and I’m very happy with it. Yes, there is a learning curve regarding things such as charging and filling the cartridge. IMO, it is totally worth it, and all those things will become second nature. If you put up with Medtronic’s crummy belt clip, you won’t mind the Tandem. I treated myself to a custom belt clip from EDC solutions T1.
Some of the things I like best: Even better A1C than Loop for me - 6.1 and I don’t eat low carb: Many Tandem staff are T1D pump users: Software upgrades mean no living with obsolete products for years while waiting for eligibility for a new pump: Tandem actually listens to users. And I could go on. Even my previously Medtronic-centric endo practice has seen the light and recommends Tandem+Dexcom.


I am just going to add my agreement with what’s been said so far. I switched from Medtronic to Tandem a little over a year ago, and Control IQ has made it totally worth it. I’ll be honest – before Control IQ, I wasn’t thrilled with the t:slim. There were no major cons, but I was annoyed with a handful of things: e.g., the clip does and probably always will slip off my waistband; I don’t like how it keeps track of history (bolus history, insulin use, etc.) compared to Medtronic; I really don’t like how much insulin it wastes when you change the cartridge; I don’t like that you can’t run the tubing out of insulin like you could on the Medtronic pumps. However, now with Control IQ, it’s totally worth it! I’ve spent WAY more time in range, and I really trust the tech.

Two more things – just like @mikefarley said, my endo used to be totally Medtronic, but now they tend to recommend Tandem. Also, the changing site process took me about two weeks to master. It’s different from Medtronic, but it’s not difficult at all.


Thanks all! I decided to go for it, mostly because the Control IQ seemed too good to pass up. All of your comments helped a lot, so thank you so much for weighing in.


A Tandem pump clip hack that works for me is a 3 inch square of shelf liner, the grip type with waffle weave. I put it behind my waistband and carefully ease the clip over the 3 inch piece. Now it does not slip off when I bend over.

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A little piece of Velcro under the clip also works very well

I’m in a wacky mood and thought we could use a little humor, so I’m sharing this pic - the “holder” could possibly be repurposed to hold a pump😊.