If you own a 2003 Marquis 2 pump spa and are having trouble with diverting valves hard to move or even if you aren't, you need to contact your dealer or factory rep as some dealers do not know that there is a revised valve for these tubs, and ask for them to send you new ones for yours. You can replace them yourself, it is not a big job.
To replace or clean the ones you have till you get new ones just point the teardrop handle to the center position and lift up, it will pop right off, then unscrew the grey piece with the icons on it and remove the valve, replace with new one, comes with new screw on and teardrop. To clean yours if they are getting hard to turn when pumps are on high just wipe them down an replace, clean the new ones every two years or if the get hard to turn.
My wife broke one of ours and I got upset with her as I told her to move valve only on low speed, I did not know that these were defective valves till I talked to the factory rep, he said what I have written here, some people have no trouble but this is a recognized recall item so you should have no problem getting the old ones replaced.
Remember this is only on two pump 2003 models the single pump Spas have no problem nor do the 2004 models.