No idea about the Keratex one but I've used the Nettex Frog Health disinfectant before and found it to be excellent. Red Horse Products are good for thrush as well (if that is what the issue is here).
I've used the Keratex Frog Disinfectant. It was very good actually. It has a little nozzel end, so you can get it right in the area/spot you need to, and you don't waste any.
Recommend - tick!