Need Help:Overflow sinking into stand

So I dont have any experience with overflow tanks, only Can/HOB filters and I picked up some side gigs about 5 months ago servicing fish tanks at Doctors and Dentists offices in my free time. Ive never really messed with any salt but so far everything I've had to do is simple ..... water change, wipe down the protein skimmer (i think thats what it is haha) and the sponges in the overflow a but the problem is my sump is sinking into the bottom of the stand and I dont know what the easiest way to get under there and reinforce the base and stop the sump from pulling down on the plumbing above. Im a union carpenter by trade so Im good with tools and stuff but Im scared I may damage the plumbing system and flood this dentist office with 220gal of saltwater! The stand is made of ****ty pressboard and the client doesnt want to get a new one because it matches all the rest of the trim around his building

Ill try to get in there soon and get some pictures

Well .... I was scheduled for tomorrow morning to fix the sinking filter issue with the stand and I ended up getting a 911 call from the office to fix an unrelated issue where the tank flooded the office.

Good news is 2 hours of double overtime ($60 an hour) fixing the tank because it was a 911 and then Im going back for 2 more hours of straight time tomorrow morning to fix the stand/filter issue.

Bad news I already worked 10 hours and had to go do 2 more hours of fish tank stuff instead of eat dinner on the couch

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Sent from my DROID RAZR HD using MonsterAquariaNetwork App

Sent from my DROID RAZR HD using MonsterAquariaNetwork App

I closed the main over flow valve drained and removed the sump and then vacuumed 14 years of salt creep and reinforced the bottom with a new sheet of 3/8'' plywood but since it has been sinking for so long the plumbing didnt match up with the hole in the side of the sump because it pulled the plumbing down I was able to get a connection and so far a good seal with no other plumbing related leaks. Organized all the cords changed out one of the return pumps with a new 700gph pump filled got everything running and ended up taking a 120v zap when I stuck my hand in the sump to reposition the heater, my first thought was a bad heater so I pulled it and I noticed the heater was fried inside so before I ran to pick up a replacement I tested the salinity and got zapped again from inside the tank but not as bad so I knew the issue was in the sump. The main electric cord runs under the tank and carpet to the other side of the office and since the place flooded yesterday I guessed the cord in the carpet could be wet so I plugged my power strip into a new extension cord and a new outlet and individually tested each electrical component by plugging it in and testing the sump with a voltometer and apparently my skimmer is shot so right now Im running with no skimmer (fine for now right? I dont even know what they do hah)