I have tried glucomannan powder.
The glucomannan powder I used is the following product :
https://www.nowfoods.com/products/supplements/glucomannan-pure-powder
Glucomannan is the main ingredient of konjac and is a water soluble polysaccharide; it is a powder made from ingredients extracted from konjac powder. It seems to work well as a polymer in bubble solutions.
I have tried the following recipe :.
6500 g water
10.3 g glucomannan powder
351g dish detergent (old version of CuCute)
(The ph was stable at 7.5 and was not adjusted. Mixed by alcohol slurry method.)
If I used plastic hoops, their bubbles self-healed well. I tried a tri-string wand with this solution.
It was 6:30 AM, 25°C, 94% humidity. The results clearly showed an overdose aspect. The bubble expanded well and had no problems with film thickness, and good conditions, but it had an extremely short lifespan and was prone to popping quickly.
On the other hand, when mixed with 4.5 g of glucomannan powder per 6500 g of water, the screen was less elastic and difficult to make bubble-in-bubble.
Somewhere in between these may be the sweet spot.