Our toilet runs constantly and I think the parts need to be replaced (Our condo was built in 1987 and I think it's original).I was looking at replacement parts, but I was trying to wrap my head around how our existing parts work and whether the replacements below would be compatible.Our existing toilet has two large cylinders. One to the left supplies the water, and another in the center above the flap. [Existing Toilet Setup](https://ift.tt/3b33TgE assuming the large center cylinder above the flap is what detects the water level in our current setup, but I've not seen a toilet setup like this before so I'm not sure.The last time I fixed a toilet was with the rod and ball setup, so I wanted to see how the newer parts (see links below) work as far as detecting when the water level reaches the right height. I'm assuming that is now done inside the cylinder to the left that supplies the tank with water?I've seen most replacement parts just have the flap without this second cylinder that our current setup has, so I wanted to make sure that one of the two options below would fix the issue and that I shouldn't be looking for different parts.[Fluidmaster 400AKRP10](https://www.amazon.com/Fluidmaster-400AKRP10-Universal-Complete-Toilets/dp/B0002YVK44)[Fluidmaster 400CRP14](https://ift.tt/3cZl6cF if I'm over thinking this or if anything is unclear. via /r/DIY https://ift.tt/2UaMQm2
