I just had a wall rendered with eco rend and within a week, some of the horizontal sections are stained from the odd leaf, bird mess or whatever. As I've just layed some patio slabs i have some stain block left over as the site I ordered the slabs from stressed the importance of stain blocking. The stain block i have is this https://nustone.co.uk/product/ltp-colour-intensifier-stainblock-1-litre/ and I've tested it or a piece of the render where you can see the water beading nicely on the left hand side. Is there any chance this would damage the eco rend in anyway before I go ahead and seal the whole thing??