GeoFil

it could be your glass is hydrophobic or too much humidity 
 

Switched back to baby shampoo and it works fine!Maybe orange tint slime does better...

Thank you Dano for the quick response!Much appeciated!

That green tint slime is a bit weak. I would get the more concentrated orange slime. 

I have to double the amount of soap when I use a tank to get it to slip properly. Also had to switch to JnJ. I think it has more wax/oily content (more cushion). My normal mix just wouldn't do it for me.
 
I did try film-on for a while but didn't like it much. 7th Generation Free and Clear is my preferred favorite most of the time.
 
Be aware that as you get to the bottom of the tank the slip seems to not be as active.
 
Most of the time I work off of bottles to change the mix with the weather/humidity and glass surface texture.