WebGL changes memory usgage

We made a serious game for WebGL. It was a lot of work to get it within the boudaries of 512 MB of memory but when we succeeded the game could be played on Chrome and Firefox both 32 bit. Unfortunately after a week the same game could not be played because of memory issues. First we could fix this by clearing the cache in the browser and restart the browser. When this workaround stopped working we increased the memory size until we hit the 32-bit browser boundary. Now we still have a perfectly good working game not working anymore and we have no clue what is causing it. Questions: - What is the best way to monitor memory usage for webgl - why does a small scene load with a big memory size but when switching to the next (larger)scene the game crashes. We do not exceed the memory reserved as the game works fine in a 64-bit browser. - Does caching influence memory usage.

We already done research on Unity answers and read all the blogs about memory usage in WebGL but still we can't figure this one out. Any help is welcome.