PEX connection to TOTO toilet

The TOTO toilet came with a cone washer and compression nut. Can I just run my PEX through that and tighten onto the threaded bottom of the flush valve? Or do I need to use one of the adapters that puts the cone washer onto a brass connector that goes through the compression nut, and then crimp on my PEX underneath that outside the nut?

Thanks for your help!

Do you have a copper stub out from the wall? Make sure to have a shut off right there.

It would be best to have a copper stub, get the adapter soldered on, then make the proper connection. Braided stainless line with the proper ends on it ist the easiest way. Pex does flex, but it doesnt look very good with all that printing stamped on it.

They do make compression shutoff valves for pex. Actually, they are exactly the same ones as used on copper, but they include an additional part. That part is something you can buy separately. It is a SS sleeve that you push inside of the pex so it doesn't collapse when you make the compression connection. Either stub out a copper bit at the wall, or run it directly to a compression shutoff, then use a conventional braided SS hose, or your choice of a supply to the toilet.

The way I did it (a DIY'r) was to crimp the pex onto a brass drop elbow with a pex barb and 1/2" female NPT, then use a 3" chrome nipple in the drop elbow and a conventional 1/4 turn shutoff, then use a braided stainless hose. Might be a few dollars more but it looks great and was super easy to do.