Seachem pH Alert Freshwater
pH Alert is a unique color device designed to be placed in the aquarium or filter and monitor pH continuously. A sensor changes color reversibly from yellow to orange to red, alerting you to shifts in pH levels between 5.4 and 8.0. Freshwater use only.
pH Alert lasts up to 4X as long as competing products.
pH Alert is also almost half the size of competing products. It’s small, clear, and unobtrusive, so it won’t detract from the view of your aquarium.
Interpretation
Simply place pH Alert visibly anywhere in the aquarium or filter and match the sensor color to the corresponding pH reading on the color wheel. It’s that easy. No chemicals or test procedures are required.
| Feature | Detail |
|---|---|
| Usage Type | Freshwater only |
| Monitoring Range | 5.4 to 8.0 pH |
| Color Indication | Yellow to orange to red |
| Duration | Up to 4X longer than competitors |
| Size | Almost half the size of competing products |
FAQ
How does the pH Alert sensor work?
The sensor changes color reversibly from yellow to orange to red based on pH levels between 5.4 and 8.0. Users match the sensor color to the corresponding reading on the color wheel for easy interpretation.
Can pH Alert be used in saltwater tanks?
No, pH Alert is designed for freshwater use only and is not suitable for saltwater aquariums.
How long does the sensor last?
The sensor lasts up to 4 times longer than competing products, providing extended monitoring without replacement.

Richard King –
I’ve used pH Alert for three months now and it’s been very reliable. The color change is clear and easy to see. I placed it in the filter and it shows pH shifts immediately. No need to do water tests every day. It’s small and doesn’t look out of place in my tank.
Rebecca Alsop –
The sensor works well and stays stable. I noticed a shift from yellow to orange after a week, which matched my water test results. It’s much easier than using liquid test kits. Only downside is it takes a bit of time to learn the color wheel.
Ryan Russell –
Great product for monitoring pH without disturbing the tank. I placed it in the main filter and it’s been accurate over the past month. The color changes are noticeable and the device is compact and unobtrusive.