<h2>Seachem Laboratories - Alert Combo Pack Ammonia & pH Alert</h2><p>Ammonia alert and pH alert employ seachem sensor technology, a sensor changes color reversible to alert you to shifts in ammonia levels an shifts in pH respectively simply place them visibly anywhere in the aquarium or filter and read anytime&#046; </p><p>No chemicals or test procedures are required&#046; </p><ul></ul>