Your pond water test, explained. Free.

Type in the numbers from your test kit and what you've noticed at the pond. Pond Chemist tells you what each reading means for your koi and fish, what matters most right now, and what to do next.

Free, with no sign-in needed. Sign in with your Play It Koi account to save your tests to your Pond Tracker.

Overall status

Needs Attention

Something in this test needs attention soon. Start with the first step below and work down the list.

  • pHLooks Good 8pH
  • Total AmmoniaNeeds Attention 0.5ppm as entered
  • Free Ammonia (NH3)Needs Attention 0.026ppm calculated
  • NitriteLooks Good 0ppm NO2 (your test)

What it found

Free ammonia is above the long-term limit

Top next step

Test your tap water's KH first. If it's 240 ppm or less (about twice your pond's 120), change 10 to 20% of the pond water.

An example result for made-up readings: API kit, 76°F, pH 8.0, total ammonia 0.5, nitrite 0, nitrate 10, KH 120.
  • 8readings explained: temperature, pH, ammonia, nitrite, nitrate, KH, oxygen and salt
  • 4ratings, from Looks Good to Act Now
  • Any kitAPI, NT Labs, test strips or another liquid kit
  • $0Free every time, with no sign-in needed

See it read a test in under a minute

One test, from the kit to the next steps. Every shot is the real Pond Chemist, and every reading is made up.

From test kit to next steps

  1. Pick your pond and your kit.

    Name your pond, or pick one you've saved. Choose your test kit so your numbers are read the way that kit reports them.

  2. Enter your readings.

    Type the numbers exactly as your kit shows them. Skip any you didn't test: a missing reading shows as Not tested, never as zero.

  3. Tell it what you see.

    How the fish act around dawn, how much the surface moves, whether the aeration ran overnight, and any recent treatment or tap water top-up.

  4. Get your answer.

    An overall rating, what each reading means and the next steps, most urgent first. Save it, download it or send it to us.

Same ammonia. A different answer.

A color chart reads one number at a time. Pond Chemist reads them together. Ammonia is far more harmful at a high pH and a warm temperature, so when you enter all three, it works out how much of your ammonia is in the toxic form, free ammonia.

Test 1: pH 7.2

Monitor
Total ammonia
0.5 ppm
pH
7.2
Temperature
76°F
Free ammonia
0.004 ppm

There is some ammonia, but little of it is in the harmful form

Test 2: pH 8.0

Needs Attention
Total ammonia
0.5 ppm
pH
8.0
Temperature
76°F
Free ammonia
0.026 ppm

Free ammonia is above the long-term limit

Two made-up tests on an API kit, both with nitrite 0, nitrate 10 and KH 120. The ratings and findings are what Pond Chemist gives for them.

Four ratings, so you know how fast to act

  • Looks Good

    No water-quality concern in this test. Keep testing and watch the trend.

  • Monitor

    Something is worth watching. Check the trend before you make a big change.

  • Needs Attention

    Something needs attention soon. Start with the first step, and call, text or WhatsApp us if you'd like a pond specialist to go over it with you.

  • Act Now

    Something may need action right away. Follow the safe steps it gives first, then call, text or WhatsApp us, weekdays 6 am to 3 pm Pacific time.

Take it to the pond. No app store.

Add Pond Chemist to your home screen and it opens like any app, ready when you're at the pond with your test kit. It works just as well on a computer.

  1. Open Pond Chemist on your phone. Sign in if you'd like your tests saved.
  2. iPhone: tap Share, then Add to Home Screen. Android: tap Install, or Add to Home screen in Chrome's menu.
  3. Open it from your home screen and type in your readings, right at the pond.
Open it on your phone
On a computer? Scan this with your phone's camera.

What a color chart can't tell you

Read the way your kit reports.

Kits report nitrite and nitrate in different ways, as nitrogen (NO2-N, NO3-N) or as the whole compound (NO2, NO3), so the same number can mean very different water. Pick API, NT Labs, test strips or another liquid kit and Pond Chemist handles it. It remembers each pond's kit for next time.

Stuck between two colors? Say so.

Pond Chemist grades the number you typed and suggests a retest in good light before any big change. On API and NT Labs ammonia charts, and API pH and nitrite, it also tells you if the riskier color would mean a higher rating.

Oxygen trouble counts too.

Low oxygen before dawn won't always show up in a test. Fish gasping at the surface, a glass-smooth surface or aeration that was off overnight all count, and fish gasping is Act Now on its own.

No risky quick fixes.

With ammonia in the water and a low pH or KH, it tells you not to raise pH or KH quickly, because a higher pH makes ammonia more harmful. It doesn't prescribe medications or algaecides. When they help, it may suggest pond salt for nitrite, a water conditioner that detoxifies ammonia, or baking soda to raise low KH slowly.

Every test on one timeline.

Signed in, you can save each test to your Pond Tracker on any device, and Pond trends charts your readings over time. Test in the morning and again in the evening, and it flags a big daily pH swing.

A person when you want one.

Copy a short summary of your result to send us, or call, text or WhatsApp Play It Koi at (206) 350-7580, weekdays 6 am to 3 pm Pacific time.

Don't guess at the color chart.

A number on its own doesn't say much. Pond Chemist puts it next to your other readings and what you see at the pond, then gives you the next steps, most urgent first. Test as often as you like. It's free every time.

Explain my results

More free help for your pond

Questions

Is it free? Do I need an account?

It's free, and you can use it without signing in. Sign in with your Play It Koi account to save your tests. We send a 6-digit code to your email, so there's no password to remember.

Which test kits does it work with?

API liquid kits such as the Pond Master, NT Labs PondLab kits, test strips and other liquid kits. Pick your kit and Pond Chemist reads your numbers the way that kit reports them.

Where are my results saved?

When you're signed in, press Save to my Pond Tracker at the end of a result to save it to your account. Saved tests show up in your Pond Tracker, on any device. Without signing in, tests aren't saved. You can still download a copy or copy a short summary to send us.

What do Looks Good, Monitor, Needs Attention and Act Now mean?

They are Pond Chemist's overall rating for a test. Looks Good means no problem was found. Monitor means something is worth watching, so retest before you make a big change. Needs Attention means something needs attention soon, so start with the first step. Act Now means something in the test or at the pond may need action right away. Follow the safe steps it gives first, then call, text or WhatsApp Play It Koi at (206) 350-7580. We answer weekdays, 6 am to 3 pm Pacific time. Outside those hours, don't wait for us: keep following the steps, and text or WhatsApp us so we can reply when we open.

My readings look fine, but my fish aren't. Why?

A test kit measures a few things in the water. Low oxygen before dawn, a recent treatment or a sudden change in temperature won't always show up in a test, which is why Pond Chemist also asks what you see at the pond. If your fish are gasping at the surface or acting differently, call, text or WhatsApp us at (206) 350-7580.

I planned my pond in the Pond Planner. Can I use it here?

Yes. Sign in with the same Play It Koi account and your Pond Planner ponds are in Pond Chemist's pond list. Pick one and its gallons are filled in for you.

Does it work on my phone?

Yes, on a phone, tablet or computer, so you can enter your results at the pond.

Does it replace a vet or a water lab?

No. It explains your results and suggests safe next steps. It doesn't diagnose disease or prescribe medications.

Your next water test, explained

Test your water, type in the numbers and know what to do next.

Explain my results