Hello Mauro,
Thanks for your response.
The original black foam and thermal pad of the card should be removed.
And please use our thermal pads which come with the water block. Please refer to the first picture of the installation guide. You will see the 1mm thermal pad has to be covered on the blue location. Sorry that it is a little wrong on the second picture and we will revise it ASAP.
Any questions, feel free to contact us.