Hi Rickynewman If you dont want to buy ro water system .Because of maintenance cost and initial purchase price of 100$+. You can use a 18l bottle and fill it with Ro Water at any good grocery store or wine supply store. it will cost around 2$ or 3$ for 18l. if you want to test Ro water on your present or next grow, you could try this. And if you decide Ro water is not for you. You wont be stuck with useless equipement!:thumbsup: