# Filling pump from insulin vial - negative pressure trick

**URL:** <https://forum.fudiabetes.org/t/filling-pump-from-insulin-vial-negative-pressure-trick/8901>\
**Category:** Type 1 & LADA\
**Created:** [December 16, 2019, 4:16pm UTC](https://forum.fudiabetes.org/t/filling-pump-from-insulin-vial-negative-pressure-trick/8901 "2019-12-16T16:16:50Z")\
**Posts on this page:** 1\
**Showing post:** 7

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**Author:** ![Eric](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/eric/32/9209_2.png) [@Eric](https://forum.fudiabetes.org/u/Eric)\
**Post date:** [December 16, 2019, 9:05pm UTC](https://forum.fudiabetes.org/t/filling-pump-from-insulin-vial-negative-pressure-trick/8901/7 "2019-12-16T21:05:18Z")

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> [@TTnyc](#):
>
> I haven’t tried your method yet, but I seem to remember that sometimes when it’s hard to pull the syringe back, I end up with “champagne” bubbles, for some reason.

A couple of things…

When you have too much negative pressure, the vacuum can cause air can seep back in behind the plunger seal. And a wider syringe barrel - like the ones that come with the omnipods - can create more of a vacuum because you would have to pull it slower to allow the pressure to equalize, compared to a narrower barrel.

Additionally, the plunger seals on the omnipod syringes are kind of cheap. So more air can sneak past them.

I don’t use the normal syringe, the one that comes with the omnipod. Because it has a much wider barrel, when you pull back quickly it creates a vacuum, and air can seep back in from behind the plunger.

Here:  
 ![image](https://canada1.discourse-cdn.com/flex030/uploads/fudiabetes/original/2X/2/2876fd44415d794a1c2c66c784a61be0784508b4.jpeg)

I find those bubbles to be horrible with the omnipod syringe. So I always use a regular 100 unit syringe. They are cheap.

The BD ones are very good. Buy a pack of these and try them out. Only about $5 for a pack of 25.

[https://www.amazon.com/gp/product/B0170PGQRI/](https://www.amazon.com/gp/product/B0170PGQRI/)

So that ⬆ is the first thing to try.

I’d suggest trying those syringes for a month, and just see if it seems like you are getting less bubbles. After you get comfortable with that, then I’d suggest trying the negative pressure in the vial.

I am not 100% percent sure who else it was here who stopped using the omnipod syringes, and had better success. @Aaron maybe?

**Reference post:**

> [@Absorption Issues](https://forum.fudiabetes.org/t/absorption-issues/2160/10):
>
> I don’t use their fill syringe anymore because it is much harder to remove all the bubbles from it. I use a regular syringe which makes it easier to clear out bubbles. Try it!

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