After every pond filter clean, record exactly four fields: the date, the sections cleaned, the findings, and the water tests from before and after. Four fields, the same four, in the same order, after every clean — that sameness is what makes koi health checks consistent, since each check can start from the last clean's facts rather than from your memory of a job done weeks ago in a hurry. Write the entry on the day of the clean, while your hands still remember which section fought back and which came away easily. An entry reconstructed later quietly loses exactly the details that matter.
A Worked Example, Field by Field
One real entry carries every field in full. Date: 12 April. Sections cleaned: the settlement brushes hosed down and the coarse sponge section rinsed, with the fine sponge section and the biological section left untouched. Findings: the coarse sponge edge worn and starting to split, a cluster of snail shells gathered against the pump intake, and leaf sludge packed deeper than usual in the settlement chamber. Water tests from before and after: before cleaning, ammonia 0, nitrite 0, nitrate 20 and pH 7.6; after cleaning and settling, ammonia 0, nitrite 0, nitrate 15 and pH 7.6. Read it back and notice what it can do: months later it still tells you which sections were disturbed, what was starting to fail, and what the clean did to the water.
Writing Each Field So It Compares
The date anchors the entry against the season and against the koi's behaviour that month, so a run of cleans can be read in order. The sections cleaned must name the sections as your own filter is arranged — settlement, brushes, sponges, biological media, whatever yours holds — and say plainly what was done to each one named: hosed, rinsed, squeezed out or left alone. The findings are for what the clean revealed, written as sights rather than verdicts: worn parts, blockage material, sludge depth, a pump that sounded strained. The water tests from before and after must be the same tests, taken the same way each time, with the before set drawn before you disturb the filter and the after set once the pond has settled again.
Reading the Record at a Health Check
A koi health check that opens this log starts further ahead. If the tests from before and after show nitrate creeping up across three cleans despite thorough work, the filter is telling you it is undersized for the stock or the feeding, and that is a different conversation from a one-off dirty week. If the findings repeat — shells at the intake, sludge in the same corner — the pond has a pattern you can change once, deliberately, instead of rediscovering monthly. If the after tests wobble whenever a particular section is cleaned hard, your own entries warn you to treat that section more gently. None of that reading is possible from memory, and all of it is possible from four honest fields.
The Same Four Fields, Every Single Time
Resist adding fields in a keen month and dropping them in a busy one, since a record with gaps reads like a story with pages missing. If a clean was partial, the sections cleaned field says so; if nothing was found, the findings field says nothing found, which is itself information a later check can use. Write numbers for tests, never summaries, and write the entry before the filter job is tidied away, while the evidence is still in front of you. Filed in that steady order, each entry joins a maintenance history that KinsLe keeps inside a Pet Passport, ready for health checks, a covering keeper or your own review next season.