I just did an experiment with a cube-sized box of Kleenex (rather than the rectangle), and it does not slide off. It can move around a bit, but it will sit there.
Worst case, and this would work with any toilet, would be to get an anti-slip mat, set it underneath the box, and then it would stay on nearly any toilet lid. These are often sold in auto accessory stores to help keep things stable on the dash, but would work just as well anywhere. They can easily be cut, if needed, so they don't show, if that's desired.
Important note - I'm not a pro
Retired Defense Industry Engineer
Yeah, they're calling it the TSU99A.X, retail $30, available for more like $21. Still a good bit more than the 528MP at Lowe's. It really is, for the most part, exactly the same valve. To ensure that the settings are uber-precisely-what-they-were-in-the-factory, they give you detailed instructions. They provide a table that shows how many "pegs" high to set the valve (i.e. tank refill level), for each and every Toto toilet, and then instruct you to install the "tamper-proof key" so the valve can't be set to use more water (unless you just peel off the key). Generally, nobody uses that key with the 528, but I guess it's a good way to ensure that the thing stays set exactly the way they would set it at the factory. They also give you this gizmo that adjusts the refill percentage to exactly what it was on the original valve being replaced, rather than the "eyeball it" method that most people use with the 528MP. For anybody who is handy, and who doesn't mind experimenting a bit to get the water level and refill where they should be, all you need is the 528MP. I do respect Toto, however, for trying to make sure that any replacement valve will provide the same level of water savings that came with the toilet.
All-in-all, it's a pretty-smart idea by Toto, and I appreciate their level of precision in foolproofing the settings. One valve on the shelf at the plumbing supply, instead of 20 different types. And it's a Made in US product. Of course, Terry was telling people to do this pretty much as soon as the 582MP came out. Toto finally caught on.
Thanks for the info about the kleenex on the toilet tank top. That anti slip material works well on many things.
I can't believe I'm so excited about getting a new toilet! I'm replacing a 1995 contractor grade toilet. As many of you know the toilets during that era were the beginning of the low flow toilets and they obviously didn't get it right the first time.
Tesla: I can believe it. I'm still kicking myself for not replacing sooner the horrible low-flow that I tore out and replaced with our first Drake. Believe me, you're among friends when you share your excitement! (Did you see the post from the guy some time ago that said that since he replaced his horrible toilet with a Drake, he's been yelling "TOTO!!!" every time he flushes it, he is so happy. Apparently, this went on for weeks, driving his wife crazy. I think it's just so nice to have something that we use every day work so well, particularly after we have had to suffer with the opposite.) The Ultramax II is a great toilet, and you are right to be excited! Just come back here for solace if your family/friends don't share quite your level of enthusiasm.
Last edited by Terry; 10-29-2012 at 12:49 PM.