Everytime I made the water too hot to dissolve the gelatin, my colloidal silver batch failed several days later.
According to Knox, .25% gelatin will completely gel water, which is 2.5 grams. At 2 grams, mine became sort of gloppy and not entirely liquid. Are you using Knox gelatin, because like maltodextrin, the gelling ability is different for different brands.
Ok. Since I'm located in Europe many of the US brands are not available here. I use a brand called Tørsleffs, which is made in Denmark. I once followed the instruction on the gelatin can, and soaked the gelatin in cold deionized water, and the water become little jellylike. And this was also the reason why I started to reduce the amount to less and less. And when I instead added the gelatin powder to the water when it was about 60 C and kept it stirring for 15 - 20 minutes, I noticed that it was not jellylike at all. So I can confirm that gelatin becomes less jelly when added to heated water (but the water cannot boil, as this will for sure destroy the batch).
Most likely, there's big differences between brands of gelatin, as the molar weight also differ a lot, but I still believe that is true - the ability for gelatin to make jelly is higher with cold water and less in warm/heated water.
So I urge you members to try this - add gelatin to water that is at least 60 C and let it stir for some time, and compare that if the same amount of gelatin is added to cold water and left there for some minutes, before the water is heated.