Several pond-related questions

Greetings group,

I have a few questions I'd appreciate some help on.

1) My mom's pond (pre-fab, perhaps 50 gallons) has a severe problem with
string algae. This is new to me, as I've been living in another state
until recently and never saw this problem in my own ponds. The pond is
quite shielded from the sun, but does have some exposure. What can be
done to eradicate this algae and keep it from coming back?

2) Does pottery need to be treated somehow before incorporating it into
a pond (as a water feature, for example)? There are no fish in the
pond, so I'm not worried about that, but I need to know if the pottery
itself should be protected from the water with something. Also, is
there anything in particular to look for when buying pottery with the
idea of using it in a wet environment?

3) I have an old wheelbarrow I'm toying with the idea of turning into a
small pond. Would lining it with heavy-duty plastic trash bags be
sufficient, or should I buy actual pond liner for it?

Thanks!

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