Normal saline is commonly used for antegrade colonic washout enemas. The saline solution is usually made at home by adding measured quantities of common salt to tap water. The best method for the carers to check the concentration of salt in these homemade solutions has not been reported. Various concentrations of saline solutions were tested for specific gravity (SG) with an aquarium hygrometer and urine analysis sticks by two blinded independent observers. An aquarium hygrometer can read SG with an accuracy of 0.00046 for saline solutions made in tap water and 0.00051 for those made with sterile water. Urine analysis dipsticks sticks failed to achieve this accuracy. An aquarium hygrometer is a simple and reliable way to measure the SG of homemade saline solutions. Its use may avoid the problems associated with over- or under-concentration of salt in the antegrade enema solution.