Seachem - Alert Series PH Alert
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.
$10 Flat Rate Shipping (Excluding All Bulky/Fragile Items, Shipping on Request).