Our Gravel?

A customer requested something I've never had requested before.
They wanted to get some fish tank gravel.
But not just any gravel.

They wanted to know if we sold the gravel out of our fish tanks.
Like the fish tanks on our fish wall...filled with water and fish (and an infestation of snails that we're trying to keep under control) and like...who knows how old that gravel actually is.
Probably 2 or 3 years old by this point. I can't quite remember when we switched most of it out.

But the customer wanted this gravel.
Wanted to know if we sold it or if we gave it away for free.
....Because apparently our sister location down south has done it before??
Who knows for sure.

But apparently because the gravel has been in the tanks for forever it's filled with the beneficial bacteria that's good for helping to establish tanks.
The customer claimed it could establish the tank like a month faster?

Which makes sense. Though with the fact that we usually gravel vacuum and scrub the tanks on a weekly basis...I'm not sure how much 'good bacteria' is there on the rocks...but i could see how it was possible.

However it was something we'd never done before here to my knowledge.
And I told the customer that this wasn't a thing.

They of course wanted me to check with a manager to see if they would allow me to give some of our fish tank rock to the customer.

Unfortunately for the customer, the manager vetoed it. 

But yah.
It was a different request than I normally get...

-Sarnic Dirchi