If I understand you correctly you have a wooden floor built over a crawl space or basement. You want to instal ceramic tiles and so you installed pressure treated plywood and now want to install the tiles.
STOP! You can NOT install tiles to pressure treated plywood. You can not even use pressure treated indoors regardless of what you're installing.
It's not even a smart idea to install tile direct over plywood, even if it was the right plywood.
Please stop and explain what you've got there and what you plan to do, please be specific.
TILE GUY - retired- TROY, MI - Consulting by phone/internet - PAYPAL
DITRA Installs - KERDI Watertight-Mold-Free Showers. I have NEVER made a mistake, I thought I did ONCE, but, I was WRONG!A+ BBB rating - est. 1987 - over 50 yrs. exp.