my leaky 90 gallon

[naesco]

Do not touch the tank.

Return the tank to the LFS immediately.
While there hand the manager a letter, copy for yourself, that includes a copy of your invoice and contains a demand for return of your money within 14 days.
If you do not hear from them within 14 days, go to small claims court on the 1th dayand sue both the lfs and the manufacturer (use their correct legal names). Do not delay. force the issue.

You paid good money for a brand new tank. There is an implied warranty that it will do the job of holding water. You are entitled to return of your money
If there was any salt restriction the LFS had a legal obligation to inform you.