Grotek Final Flush

Hi Greg, thanks for your question. Firstly, to clarify, this isn't a cleaner, but instead, it's a flushing solution to help the plants lose the last of the nutrient residues at the end of flowering. I've edited the description to make this more clear. I don't see how this would cause damage to the Neoprene collars, I find it highly unlikely that a product designed for use in hydroponic systems would be detrimental to one of the principal parts of said system. In any case, unless I'm mistaken, if you're adding it to the nutrient tank then it shouldn't come into contact with the neoprene collars! I hope that answers your question, all the best and happy growing!