Buying list
This is the complete buying list from a real build: a 232-gallon fish pond, hand-dug in dense San Francisco clay, six weeks from bare corner to cycling water. Every price is what was actually paid. It is organised by what you need and when, not by where it was bought, and it ends with the part every starter kit leaves out: what it takes to make the water safe for fish.
Read this first. Size everything to a measured volume, not a guess. The box formula on this pond said 596 gallons; the traced measurement said 232. Pumps, filters, dechlorinator and stocking all key off that number, and getting it wrong by 2.5x buys the wrong pump. Measure yours before you buy anything on this page.
The liner is the one component with no acceptable failure mode, and it is the most expensive single object in the pond. Buy the good one. Everything else here is protecting it.
| Item | Why | Paid |
|---|---|---|
| Firestone PondGard 45-mil EPDM liner, 15 × 15 ftSized from the outline's true spans plus depth and a fold allowance. A 10 × 15 was bought first and returned once the volume maths said it would not reach. | The pond | $244.41 |
| 8 oz non-woven geotextile, 6 × 100 ftUnder the liner against anything sharp in the soil; over it against the slate. | Protects the liner | $57.46 |
| 20-mil HDPE sheet, 7 × 10 ftOffcuts for the falls corner and any hard edge. | Extra protection | $19.75 |
| Poly landscape edging, 3 in × 40 ft, with 36 spikesDefines the rim line the coping is levelled to. The stone must clear its lip by about half an inch, never bear on it. | Rim | $27.15 |
| Landscape staples, 100-pack | Pins the edging | $10.52 |
| Sakrete Paver Base "Step 1", 12 bags at $6.25Compacted in two-inch lifts under the coping shoulder. The cheap all-purpose sand is the wrong thing: it flows rather than locks. | Base under the coping | $82.41 |
| Sakrete Paver Leveling Sand "Step 2", 3 bags at $7.28The screed goes under the liner. Sand on top of the liner is cosmetic only. | Levelling screed | $24.00 |
| Black slate flagstone, 503 lb at $0.79/lbDry-set, no mortar, on purpose: mortar locks in mistakes and cracks with seasonal clay movement. Bought from a landscape supply yard by the pound. | Coping and falls | $436.61 |
| River rock, from a neighbour | Falls and margins | $40.00 |
| Great Stuff Pond & Stone foam, 2 cans | Seals the falls stone | $28.20 |
| Heavy-duty basin grate, 4-pack, 32 × 16 inSits on the ledge ten inches below the waterline with one six-inch access hole. There is a toddler in the household; this is not optional. | Safety | $119.48 |
The 500-pound line. The slate yard charged $1.09 a pound under 500 lb and $0.79 at 500 and over. Buying 503 lb cost $397 before tax; the same weight one pound under the break would have been $548. Once you need more than about 365 lb, buying 500 is cheaper in absolute terms. Ask where your yard's break is before you load the car.
Two pumps, not one: a big one for the day and a small one for the night. The falls keeps running, the oxygen keeps going in, and the electricity drops by three quarters overnight. The filtration is split in two on purpose: the canister takes the mechanical load and gets backflushed, while the spillway box at the top of the falls holds media that is never disturbed.
| Item | Why | Paid |
|---|---|---|
| VIVOHOME 100 W submersible pump, stepless 700 to 1800 GPHTurns 232 gallons over about eight times an hour wide open. Size from your measured volume with the pump calculator. | Day pump | $63.99 |
| Simple Deluxe 800 GPH pump, 24 W | Night pump | $20.41 |
| VIVOHOME 1580 GPH pressurised bio filter, with a spare sponge setMechanical load, backflushable. | Filter | $160.85 |
| 10 in filtering waterfall spillwayThe undisturbed biological stage. Holds crushed coral, bio-balls and rock. | Falls header | $60.12 |
| Reinforced pond tubing, 1 in × 10 ft | Plumbing | $17.59 |
| Brass hose barb reducer, 1¼ to 1 in | Plumbing | $16.99 |
| PVC ball valve, 1 / 1¼ inThrottles the falls without throttling the pump. | Plumbing | $14.62 |
| Filter media mesh bags, 10 pcs | Holds the coral | $16.28 |
One field note that belongs on a buying list: a nut on the falls connection that was not fully tight let roughly forty gallons into the ground and turned the clay at that corner to pudding. Check every connection with the pump running before the stone goes on. The right response afterwards was to do nothing; saturated clay cannot be compacted.
New water will kill fish. Not eventually; within days. Two things are wrong with it, and both are fixable with cheap supplies, but only if you know they are on the list.
Chloramine. Most city water is treated with chloramine rather than chlorine, and chloramine does not off-gas. Leaving a bucket out overnight, which works for chlorine, does nothing. A dechlorinator that specifically names chloramine handles the chlorine, the chloramine, and the free ammonia the chloramine breaks into when it is neutralised.
No bacteria. Fish excrete ammonia. In an established pond, bacteria living in the filter convert it to nitrite and then nitrate, which plants take up. A new pond has none of those bacteria. Growing them is called cycling, and doing it before there are fish in the water is called fishless cycling: you dose a small amount of pure ammonia yourself, test daily, and wait until the colony can clear it to zero. Weeks, not days. Nothing goes in until ammonia and nitrite both read zero with nitrate present, held across several days.
Buffer. Very soft water, common where supply comes from mountain snowmelt, has too little carbonate hardness to hold pH steady while bacteria consume alkalinity, and a pH crash stalls the cycle. This pond's tap water measured around 20 ppm KH; the target is 80 to 120. Crushed coral in the falls header dissolves in proportion to how acidic the water gets, so it self-regulates instead of needing dosing.
| Item | Why | Paid |
|---|---|---|
| Seachem PrimeNames chloramine on the label. Dose to the measured volume. | Dechlorinator | $54.00 |
| API Freshwater Master Test Kit (liquid)Liquid, not strips: strips are not reliable enough for the two numbers that gate stocking, ammonia and nitrite. | Testing | |
| CaribSea crushed coral, 15 lb | KH buffer | $31.49 |
| Bottled pure ammoniaJanitorial grade, no surfactants or scent. It should not foam when shaken. | Fishless cycling | about $12 |
| Bacteria starter (API Pond Quick Start or similar)Optional; shortens the cycle. A squeeze of dirty filter sponge from an established pond does the same thing for free. | Seeds the cycle | optional |
Check dosing against the product label, always. The ammonia calculator turns a test-kit reading into the free ammonia fraction that actually harms fish, and the water-change calculator tells you how much to change to bring a reading down.
Plants go in during cycling, not after. In a pond this size they are the export path for everything the filter converts but cannot remove. This pond gets no direct sun, which rules out water lilies, lotus and floating plants; what went in were shade-tolerant marginals and a submerged oxygenator: dwarf red-stem parrot's feather, Japanese sweet flag, water forget-me-not, creeping Jenny, with hornwort still to come as the main nitrate sponge. Live moss for the stone joints was another $47.78 across two orders.
Fish last. Four juvenile shubunkin for this pond, about $40. Koi were ruled out on arithmetic: every variety is one species, they want a thousand gallons or more, and there is no dwarf koi. Check your own numbers with the stocking calculator, which reads both the surface area and the volume of your trace.
| Item | Why | Paid |
|---|---|---|
| Green 4×360° laser level with tripodThrows the waterline across the hole. Every height afterwards is measured down from it. | Datum | $64.08 |
| Telescopic skimmer net | Leaves | $24.95 |
| Ordered online, 19 items | $1,035.60 | |
| Bought in person (stone, base, sand, water treatment, rock, staples) | $647.53 | |
| Getting 2.5 tons of clay out of a back garden: $400 in fees, $400 in labour | $800.00 | |
| Spent so far | $2,483.13 | |
| Still to come: fish, hornwort, ammonia | $67 | |
| Finished pond | $2,550.13 |
The fish are the cheapest part of a fish pond. The single largest line, nearly a third of the whole thing, is the dirt that had to leave. Budget for the hole, not just what goes in it.
Product links are plain links to the items that were bought. See also: planning a pond from satellite imagery.