Fill the jar we provided almost to the top with the water you're testing — it holds about 100 mL (3.5 oz). Leave a little room for the 1 mL vial of reagent solution you'll add next. Volume matters: your result is reported per 100 mL.
Add the vial, swirl gently, and wait 15–20 minutes. Two vials? Add the first, swirl, wait 15 min — then the second, swirl, wait 15 more.
Cover the jar while you wait — dust from the air can land in an open jar and get counted.
Unscrew the holder, set the round filter membrane inside, and screw it back together.
Open the holder, drop the filter in, twist it shut
Twist the assembled filter holder onto the syringe tip until it's snug.
Twist the holder onto the syringe tip until snug
Pour the prepared water into the top of the syringe. It holds 60 mL, so you'll fill and push it about twice.
Push the water through right away — don't let it sit. Everything we count is caught on the filter surface.
Unscrew the holder and take out the filter. Keep the side that faced the water pointing up — that's the side we image.
Place the filter inside the imaging box, collection side up.
Set the glass on the box lid — it rests in the square indentation.
Slide the flashlight into the rectangular hole on the top-left of the box.
Open your camera app, rest the phone flat on the box with the lens over the glass, tap the glowing filter to focus, then shoot.
Turn on Night Sight. No exceptions.
Without it, the camera won't pick up the glow and your count will be useless. Takes 5 seconds.
Upload the photo you just took. Our particle counter reads it on the spot — your microplastic count appears right here, and a verified report follows by email within 24 hours.
Instructions
Run one water sample at a time. Most of the 30 minutes is just waiting after you add the vial.
Fill the jar we provided almost to the top with the water you're testing — it holds about 100 mL (3.5 oz). Leave a little room for the 1 mL vial of reagent solution you'll add next. Volume matters: your result is reported per 100 mL.
Add the vial, swirl gently, and wait 15–20 minutes. Two vials? Add the first, swirl, wait 15 min — then the second, swirl, wait 15 more.
Cover the jar while you wait — dust from the air can land in an open jar and get counted.
Unscrew the holder, set the round filter membrane inside, and screw it back together.
Twist the assembled filter holder onto the syringe tip until it's snug.
Pour the prepared water into the top of the syringe. It holds 60 mL, so you'll fill and push it about twice.
Push the water through right away — don't let it sit. Everything we count is caught on the filter surface.
Unscrew the holder and take out the filter. Keep the side that faced the water pointing up — that's the side we image.
Place the filter inside the imaging box, collection side up.
Set the glass on the box lid — it rests in the square indentation.
Slide the flashlight into the rectangular hole on the top-left of the box.
Open your camera app, rest the phone flat on the box with the lens over the glass, tap the glowing filter to focus, then shoot.
🌙 Turn on Night Sight. No exceptions.
Without it, the camera won't pick up the glow and your count will be useless. Takes 5 seconds.
Upload the photo you just took. Our particle counter reads it on the spot — your microplastic count appears right here, and a verified report follows by email within 24 hours.
Both of these make a sample with plastic in it look clean. If your screen suddenly shows nothing, check these before you trust the result.
By far the most common reason a real sample reads as clean: the 25 mm filter disc is curled. If it curls or buckles, the light hits it unevenly and you get dark patches that look like nothing's there — that's shadow, not a clean filter. Handle it with the tweezers — that's what they're really for, keeping it flat matters more than contamination — and get it lying completely flat before you image.
Trick: dab it with a paper towel to a slightly damp state. A little moisture makes the disc stick flat to the surface; bone-dry, it tends to curl.
The flashlight sits in a fixed position, so aiming isn't the problem — the batteries are. Below about 50–70% charge, the blue light stops exciting the dye and nothing glows, even with plastic on the filter. If particles were showing a moment ago and then vanished, swap or recharge the batteries before you assume the sample is clean.
The box blocks room light and lines up the filter, flashlight, and camera. Microplastics caught on the filter glow under the blue light — those are the particles we count.
Once the box is set up, the app walks you through capturing and counting the particles.
Have two tests? Run one on unfiltered tap water and one after your filter.
Wash the jar thoroughly. Don't drink from it.
The Refill 4-pack covers 4 more runs — keep the blue light, syringe, glass slide, and imaging box you already have. $28.
Stuck on a step? Use the chat in the bottom-right corner — we reply fast.
Don't have a kit yet? The microplastics test kit is $75. Tests are sold separately.