Seeing your setup gave me an instant and interesting idea....
Paint the pots with off-white and dry brush with a light grey. then seal with a light layer of silicone.
replace the trailerpark esque concrete with concrete coated foam, shaped like old broken greek pillars, painted and sealed to match the terra cotta. these should be all the way to the top of the water.
Pile broken white rocks around to give the impression that things are broken/crumbled.
Everywhere else, a plain brown medium sized substrate.
Perhaps a small bust of Plato somewhere....
voila, instant ancient greek ruins - Just add water.