I always overwintered my pond fish in kiddy pools (Oct thru April), I have use Intex (400 gal), and Bestway (@ 1000gal).
Both have worked well. Filter media in bags in line with the flow from a pump or powerhead has also worked well, along with rocks, logs and other stuff from the ponds, that would obviously contain beneficial biofilm.
Intex


Bestway


Both have worked well. Filter media in bags in line with the flow from a pump or powerhead has also worked well, along with rocks, logs and other stuff from the ponds, that would obviously contain beneficial biofilm.
Intex


Bestway

