In order to compare these, you would need to multiply the 5 gallon to match the 25 gallon. in which you would multiply by 5. because you multiplied the 5, you also need to multiply the 11. when you multiply 11 by 5 its 55. so your total comparison would be $55 for 25 gallons vs $51.05 for 25 gallons. Obviously the cheaper one is better.