Methods for treating manure treatment systems in confined animal feeding operations to maintain the agricultural equipment, alleys and lagoons in a safer and more effective and useable condition though the use of a sulfuric acid composition. The first fiber reinforced thermoset composite material layer has glass fibers in a vinyl ester matrix. The components in the treated test medium react with components in the test fluid providing a visual indication, for example a color change, to judge the condition, the presence of a marker substance or another parameter of the fluid.