TSlim and G6 - some concerns

I am supposed to go on the G6 when I get my next transmitter. And my Medtronic Paradigm pump is out of warranty so I can choose a new pump. I have seen many posts and believe many are a proponent of TSlim and is many features. I’m considering changing to Tslim and G6 but have the following concerns.

G5 is fine for me and I’m having my best month at ave Bg of 103 and std dev of 18 and TIR of 99%. Have read that Tslim is great for TID who have AIC of 6.5 and higher who want to improve. Not so good for people that have an AIC of 6.0 or less and want to maintain.

Many Tslim users appear to be aggressive and put in data to compensate for the fact that their readings are initially off at least at first. For example, if I’m correct, you don’t have the flexibility to set threshholds at which adjustments are made to keep you in range.

If I dislike the Tslim can I shut of Basal IQ and Control IQ and would it then operate as a standard pump with me making all the decisions?

Is Basal IQ as good as I read? I NEVER EVER shut off my basal as I simply take fast acting carbs to raise my BG when I am low. Shutting off the basal will affect my readings for 4 hours whereas food will affect my readings for only 1 hr.

I have heard that Tslim makes basal changes based on predictive values. So is predictive value based on my personal input such as correction factors, IOB, duration, etc. or does it make predictive values based on external factors that I would not consider? Does Basal IQ work for you and do you believe it in theory?

Finally I dislike the fact that Tslim will make basal and bolus decisions based on the CGM which is sometime inaccurate. I still take blood tests because I don’t trust the accuracy of the CGM so this seems like I am going way overboard trusting Tslim to make basal and bolus adjustments based on CGM datapoints?

Do I have legitimate concerns? Would lover your opinion.

First off, Basal-iq and control-iq are completely different. I’m not sure if you can still get basal-iq for a tandem pump anymore. All new pumps are shipping with control-iq as of the last few weeks of January.

Users of the pump are not manipulating or compensating their settings for readings being “off”, I’ve no idea what that even means.

I suggest you reread the post you originally asked this same question about on TUD again. There’s enough info there to explain why myself, Robyn and Hammer are doing what we are and not fooling or trying to manipulate the pump in any way. Here’s the discussion about control-iq from this site:

To answer your question about a1c, it’s your decision. If you want to sugar surf at 80-90, this is not the pump for you. If you want your BG to run consistently at 110 without having to interact with the pump at all, control-iq is wonderful.

I’m guessing your on Medicare with your statement about being moved to it now. Trusting the CGM is going to be the only way for you to see your BG now anyway. Medicare has stopped coverage on test strips for anyone on a CGM starting this January, no matter what the secondary insurance says. Unless you buy strips out of pocket, the CGM is your only option to see your BG.

So I can’t answer whether or not Control IQ is correct for you. I can let you know that all of the algorithms can be shut off and you can use the Tslim like any other pump. We are coming up on 5 years of use mostly as a pump, the last year or a little longer with Basal IQ. We really like Basal IQ and its ability to land highs effortlessly. I know you say you just eat carbs, and that is what we used to do, but if your correction is close Basal IQ is effortless. This is mostly because as soon as your blood sugar starts to go up it turns the insulin back on, so we don’t get rebound highs from reduced insulin. In fact, there are many nights my son will deliver a correction dose before bed and he will just skip along between 80-90 with Basal IQ shutting his insulin off a bunch of times. This algorithm has allowed us to be more aggressive in our treatments and spend less time high. Whether or not Control IQ will work as well is an open question that we are currently debating.

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Chris, thanks for your insight. I would enjoy the break that would result from not having to manage as closely myself. There is very little downside and tons of upside if I can turn it off and just use it as a pump. Still don’t understand the theory of shutting off basal but enuff people swear to this predictive managment.

The reason is that unlike other algorithms as soon as the blood sugar goes up (even if it is below 80) insulin is started again, so shutting off insulin and being aggressive about restarting it means you don’t have many issues. Here is a night my son got a full nights sleep with no alarms because Basal IQ shut off his insulin 9 times. Each of the little blips is a shut off restart.


At what age did was your son dxd? I was 15. Did you son sleep until noon? I understand he got a full nite sleep, something I never get, but I would have been upset it bg rose to 200 unless this was from eating breakfast.

He was 12. No he got up around 9 and ate breakfast and went to work. He used to be quite upset going over 200, but it is a bit more routine that I would like, which is why we are thinking Control IQ might help him quite a bit. Nobody in my house is sleeping until 12 unless they are sick. We are hoping once he gets through college he takes things a bit more seriously as far as control goes. With that said he is maintaining an A1c in the high 6’s and low 7’s, so there is not that much to bitch about really.

So it simply went up from a meal. Sounds good. I used to spike well into the 200s after a meal. It is so much easier to manage now that I am retired and have a CGM. But again it takes a lot of time. Kids and even working adults don’t have the luxury of time. But if I can stay around 6.0 and highs around 50 I’ll take that if it minimizes the effort.

But at least they have the luxury of technology. When I was dxd there were no disposable needles. We boiled steel needles and not as often as we should have. And no such thing as AIC or even testing blood. We used to put a big pill in a big test tube and put 5 drops of urine on to see if turned blue (glucose<150), green (<250), orange (350 or higher). That was it. The good o’l days!


Maybe not good for your diabetes care, but certainly good from the mental health aspect. It is very easy to obsess with all the data and effort required to control things today. I think some of our members who were diagnosed in a similar vintage to you, look back on those days fondly, since there wasn’t much else you could do.

Looking forward to seeing how things work out for you on the pump front.

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Hi there. I can’t tell you if the Tslim is the right pump for you since I think it’s such a personal choice. However, I can try to answer some of your questions from my perspective using the Tslim x2 with dexcom g6 (since August).

1st off - your BG control sounds super incredible, so congrats on that! If you do not want to use Control IQ or Basal IQ, then the tslim x2 can be used as a “dumb pump” as some others refer to it. It can receive cgm input but all the basal adjustments reliant on the cgm data (ie. Basal IQ and Control IQ) can be turned off, allowing the pump to operate similarly to your current medtronic pump.

My A1c is in the 5s, and I am able to be comfortably more aggressive with my management thanks to basal IQ. For instance, most nights I sleep alone and I will crank up my basal so that my basal is pushing me down and covering anything left from dinner/desser that could be raising me, but Basal IQ will suspend me when I start to go lower. So like @Chris’ son, most nights I’ll just skim around 80-90. On other pumps, I wouldn’t feel comfortable with increasing my basals at night without Basal IQ to catch me if going low.

It may be worth your time to figure out if you were to move over to tandem if you would be able to get a pump with basal IQ vs control IQ functionality because they do vary in management.

Predictive value is based solely on readings coming from dexcom. The pump looks at where your dexcom numbers have been reading and where they are trending. I prefer my pump to not incorporate other input into its algorithm because other factors (like IOB and duration) aren’t super reliable (site to site, and fluctuating insulin sensitivity/resistance) and because I take a decent amount of insulin via injections (that the pump would have no way of knowing about).

For me, most days Basal IQ works really great! I keep it on most of the time, but there are days or times where I don’t want to have any suspensions and I’ll turn it off, and then the pump works just fine then too.

I find that the first 24 hours after dexcom g6 insertion that the sensor is not reliable/accurate. I will not use Basal IQ in the first 24 hours after sensor insertion. For me, the dexcom g6 is accurate (nearly always within 10mg/dL) but of course the accuracy varies person to person. I feel comfortable trusting the CGM data, though I do finger tests a couple times a day to back check the CGM.

It seems your pumping system works for you and if don’t want to mess around with the idea of basal IQ or control IQ then it may be worth it to look into other pump models/manufacturers (if your insurance will cover it). But if you think basal IQ or control IQ could be a nice resource to have in the back of your pocket then it may be worth it to think more the tandem route, with the knowledge that you could use the tslim as a regular “dumb pump” if you’s prefer. That’s just some of my thoughts on it all. I hope that helps, but it really all is a personal decision on what works for you and your BG management!


Thanks for all the effort that went in to your very responsive and instructive post. I have developed my own management algorithm :smiley: that I will have to change if the TSlim works as effectively for me but that is a change I will gladly make. And you are the first person who was able to give me insight into predictive value. I am glad they simply do not extrapolate based on user input. I think what we have learned are the basics but it is just as important or more important to be reactive than proactive. TSlim as you describe seems to manage the reactive time that is so much effort. As you might expect I hope to cut down on the finger sticks once I get the G6 but if do not then at least the TSlim has advantages that should be very worthwhile. Thanks again and good running. :sweat:


It is certainly a personal decision, but from what I’ve seen, the Tandem approach with TSlim is a lot better than Medtronic’s. Just saying. (And I’ve never used a medtronic pump and have been three years on the TSlim).

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