Use this 8x10" (200x250mm) sheet of red litmus paper for testing alkaline (basic) water splatter or leaks, only $1.50. They can also be ordered as large as 20x24" (500x600mm); but minimum order of 100 sheets is requred.
You can use a paper cutter to make your own custom sized strips from this sheet. Or, buy as short, narrow precut red litmus test papers in a stoppered bottle.
A: Any alkaline aqueous (water based) solution. Effect is most noticed where solution is greater than pH 9. Found out more in our blog: How Does Litmus Paper Work?