I hate pond tubbing because it leaks lol and love clear vinyl tubing because it doesn't. I prefer straight PVC though. Depending on how this thing gets going I might go back and plumb it hard line or something like that.
Some day I hope to have my setup static enough in its configuration to use all hard PVC. The Hayward is a big step in that direction as I have been very happy with it and don't forsee changing it any time in the future.
I have to confess that I kind of enjoy re-engineering and improving my setup. Someday when everything runs perfectly, like it envision it should, I will probably get bored with it... LOL!!!!
The flow will be between 4,000 and 6,000 GPH (have to test my tanks and see what works best and have to install air line before I can finish setting it up for testing.). I spent all weekend laying the pipe for the 300 gallon super sump that will service 800 gallons of aquarium. I could really use your input here. Should I get a larger single DE filter or run two smaller ones?