I was on the fence about getting these but I saw some positive reviews. Since I didn't have a liquid test kit yet, I took a chance. When I first got it I made sure to carefully peel the film off as not to damage the little detector dots. And I was extremely careful about not touching the Ammonia Alert sensor. So I put them in Python's tank. The ph alert adjusted in a few hours as expected, but I gave the Ammonia Alert a week and it stayed a weird gray color. So I took it out of the tank. It sat out for a few weeks until I bought a bottle of pure ammonia to test it. I held it over the bottle and it immediately turned to the darkest shade. Confident that it worked, I put it back in Python's tank and watched it adjust back to the "safe" yellow. When I moved Python and the two alerts from the little hex tank to the slightly larger cube she's in now, I noticed the suction cups were cloudy. Then I noticed small bits of a film like substance floating in the water, thinking it was something I might have had under my fingernails, I sucked all the pieces up with a turkey baster and continued with the move. Now back to the inaccuracy. Once I got the API test kit, I tested Python's water. The ammonia was over 1 ppm and the Ammonia Alert said it was within a safe level! Now I've heard that test kits measure ammonia AND ammonium but the alert only measures ammonia, which is why there's such a difference. But I don't know how much truth there is in that. The PH wasn't that important but it was still wildly inaccurate. I knew the alerts weren't accurate but I kept them in the tank since Python liked swimming around them. I recently decided to take them out(the cloudy suction cups worried me) and the water was immediately clouded with long, clear, stringy... I don't even know how to describe it. Slime? I sucked a lot of it out with my trusty turkey baster, but there's still little pieces floating in the tank, I'm considering a 100% wc... So please, don't waste your money on the Seachem PH and Ammonia Alerts, stick to the liquid test kits!