We've heard that some Farmers are unable to use their Water Certificates. By game design, it cannot be used when another resource buff is active or placed on the Farm. This includes unlimited fertilizer buff, unlimited speed-grow buff, and even the machines such as Speed-Grow Machine, Instabloom, or Instagrower Machine.

 

If there's a Speed-Grow Machine, Instabloom, or Instagrower Machine placed on your Farm, the "Use" button on any of your Water Certificates will remain grayed-out.