The chair has a handle on the right side that allows the chair to go to full height when not occupied. After it is occupied an hour or so, the chair sunks to the lowest level. I do not see any liquid leaking. Is there some adjustment I can make or seal to replace? If so--how do I do it?
check for an adjustment screw or knob
The seal is leaking and is slowly letting the hydraulic fluid seep back to the reservoir. If you're mechanically inclined you can disassemble it and replace the seal. If not, it's probably cheaper to get a new chair.
Find out who made the chair and if they have a web site. They might have advice or replacement parts. If the chair is company property, maybe you can ask for another chair. If it is yours, maybe it is under warranty.
The chair is supported by what amounts to a shock absorber ,much like the ones on a car. You didn't say how old the chair is but I think it must be old enough for the shock to have worn out. Either put up with you sink-o-matic chair or recycle it and get a newer model. The cost of repairing it, even if you could, would hardly be worth it unless you have a really big sentimental attachment to it.
