Coach Jonathon talked a few episodes ago about how studies show the most effective cooling fuel is a “slurry”. Better than ice cold liquid, or liquid with ice etc. Since then, I’ve tried many times to make a slurry for my indoor threshold/vo2 rides with my blender (Vitamix). I’ve not been able to really get any sort of consistent “slurry” texture, so not like an icy frosty, not like just cold liquid, but that thick just not quite frozen liquid that I understand makes for a “slurry”. I’ve tried it with my carb powder and without. No dice, no “slurry”, just water and ice, or chipped ice flakes, or a blender that spins the ice in place. What is the magical recipe that will guarantee I’m not wasting an extra half hour before my ride trying deal with flying ice cubes and wasted drink mix, and instead am crushing that threshold with my insides radiating a comforting chill throughout my body?!?
Dude! 7/11 + Any numbers of flavours = Speed.
It doesn’t technically need to be a “slurry” the key is to have ice in your stomach. So chipped ice is fine. It’s just that the slurry texture is easier to drink than a liquid with ice chips in it.
In terms of actually making it…idk. Most slushy makers use a paddle to move the liquid as it freezes as opposed to trying to break up large ice cubes. Though a vitamix should be able to break down ice cubes into a drinkable texture.
Commercial slushies use Glycerol to get that texture you are after.
Careful you don’t fall down a hole looking up studies on the effects of glycerol on hydration and exercise performance.
We had a blender like yours until I broke it. It made ok smoothies. Suffered from the issue you have. Had 1 set of blades on the bottom.
We got a Ninja blender. This difference is the Ninja has a tower of 3 sets of blades. There is a big difference in the texture. It makes the slurry you are after. You will have to play around with the liquid to ice ratio. If you use a drink mix powder I recommend you mix that in a small amount of liquid in the blender before adding the ice. There are 2 issues I found. Over mixing causes it to become too foamy. Adding protein powder at the start will also make it foamy. I add this last and mix until it’s incorporated. My Ninja has a smoothie setting where it does all the mixing ( high, low, starting and stopping) then shuts off when done.
ninja makes a home slushie machine. also good for making summer post ride drinks 
From my experience using a vitamix for margaritas you need way more ice than you think you need. Also liquid.