Draining and refilling - Concrete bottom / Fiberglass sides - 40+ years old

[jonnyrr77]

We have a concrete bottom, fiberglass sided, 25,000 gallon, 40+ year old pool with a ton of unsightly staining on the concrete that we have been living with since acquiring the pool in 2012. My guess is someone let it sit with debris and it ended in permanent staining. For aesthetic purposes only, we would like to drain it completely, then use a pressure washer and bleach to remove as much as the staining as possible. My sole concern is that I don't want the walls to cave in or crack and I don't want to float the concrete bottom (if even possible). What steps can I take to prevent any of these disasters from happening?

Thank you very much for the advice.

 

[duraleigh]

Is the water table high where you live? That's the first step.

 

[jonnyrr77]

Is the water table high where you live? That's the first step.

I live in suburban Kansas City. I am unable to find water table information online, so I may need to call the city or the county extension office tomorrow. Do you have a suggestion on how I could figure it out? Thanks.

 

[gwegan]

Could you post some pictures of your pool?

My concern other than the obvious water table one is whats holding the sides up? Are the fiberglass walls in good enough shape to hold back the walls without the support of the water? There may be no way to answer that question without taking the water down. Its been there 40 years so this may not be an issue.