As a novice to all of this, I continue to have questions. The system I'm building is flood and drain with a 500 gallon fish tank with a 1:1 grow bed ratio. First, I'm planning on using 1/2" delivery pipe and 1" drain pipe. The 1/2" was based upon the recommendation in Sylvia's book. Also, per her book, I'm planning to not cement any of the joints. This part especially concerns me. Any thoug…