Adding Substrate?

[term_22000]

As the title says, can adding substrate be done once the tank is established without destroying the tank already? Over the last couple years I have slowly lost substrate and am starting to need more. My plants aren't taking root anymore like they should.
Any Ideas would be great. If the tank needs to be redone then so be it but I would rather it not.

 

[Fish are AWE]

Yes. Though not to stress the fish add your substrate slowly and remember it has to be clean for the fish. How'd you even lose substrate in the 1st place?

 

[term_22000]

Just being new to substrate and vaccuming it up

Learned after awhile though