Shrimps died, Profito gone bad??

Pic of my frog "Kikkert" for the algorithm

So, in about a week and a half time about 15 of my +-20 red cherry / red Sakura shrimp died, a big glass shrimp, a big Japonica shrimp and an unknown species snail. There's also some biofilm forming on the watersurface. Fish and frog don't seem to be affected.

All my watertests came back normal, filter is running normally etc. The only thing i can think of that i did differently than usual is that I added a little bit of Profito from an older bottle. Which I have used before, but that's quite a while ago. Could it be that the Profito has gone bad and that this killed my shrimps?

If so, do I need to do something special to get the toxins out of the water besides water changes? TIA!

Pic of my frog "Kikkert" for the algorithm

So, in about a week and a half time about 15 of my +-20 red cherry / red Sakura shrimp died, a big glass shrimp, a big Japonica shrimp and an unknown species snail. There's also some biofilm forming on the watersurface. Fish and frog don't seem to be affected.

All my watertests came back normal, filter is running normally etc. The only thing i can think of that i did differently than usual is that I added a little bit of Profito from an older bottle. Which I have used before, but that's quite a while ago. Could it be that the Profito has gone bad and that this killed my shrimps?

If so, do I need to do something special to get the toxins out of the water besides water changes? TIA!