Retail supplies post-install

[Stonehenge]

We've just begun getting into pond installs - did one last fall, have a few to do this year.

I'm wondering, for those who DON'T have a retail center, do you provide subsequent sales of retail supplies, like filter mats, algae buster, stuff like that? If so, do you deliver it? Mail it?

Or do you just refer them to their local pool/pond retailer?