Liners & Construction

Building, expanding or patching a leak. Firestone PondGard 45 mil EPDM liner, double sided butyl seam tape, patches and expanding foam for setting rock. EPDM is fish safe, stays flexible in the cold, and is what we use on our own systems.

Measure twice before ordering liner: add double your deepest point plus two feet to each dimension so you have skirt to work with.

Rolled EPDM pond liner, butyl seam tape, a round liner patch and a can of expanding foam on a stone ledge beside a koi pond, for building and repairing koi ponds.

Worth knowing before you buy

Ground rules and answers from the ponds we run every day in San Jose.

Know your real gallons

Every number in this hobby is dosed or sized by volume. Measure once, write it on the filter housing in marker, and stop guessing. Most people overestimate by a third.

Common questions

How do I work out how many gallons my pond holds?＋

Length times width times average depth, all in feet, times 7.5 for a rectangular pond. For a round or oval pond use 5.9, and for an irregular shape use about 6.7. Average depth matters: measure it in a few places and take the mean rather than using the deepest point, or you will overestimate badly.

The calculator on our Pond Supplies guide does the arithmetic and turns the answer into pump, UV and air recommendations.

I am not sure what I need. Can you just tell me?＋

Gladly, and this is genuinely the fastest route. Send us your pond volume, your depth, roughly how many koi you keep and how big they are, your plumbing size, and the height from the pond surface up to your filter return. That is everything we need to size a system properly.

We have been building and maintaining koi ponds from San Jose since 1998, and we run this gear on our own systems. We would rather talk you into the right pump than sell you the biggest one.

Have us size your systemFull pond guide & calculator