Hmmm, first thing is keep it simple! Are you talking about flexable PVC or the tubing? For ease of construction I would go with the flex PVC. It will fit into regular PVC fittings and wont restrict flow like if you had to use barbed fittings with the tubing.
Where the flex (PVC) has the most value is in reducing the number of flow robbing elbows and 45's and also reduction of that annoying reverberation caused by the return pump vibration. On the drains you could hard plumb to the sump as there is no vibration to worry about and this may actually make it easier to add a noise reduction set up when it gets to the sump. (it gets loud with all that water splashing into the sump!) On the return side of the pump I would attacj a true
union ball valve to the exit side of the pump (both sides if its an external) this will allow you to colse of the return plumbing for pump cleaning etc. and when your done you just put it back on! After the valve is where I would use the flex. Use it all the way up to what ever you have in mind for the return set up. The flex PVC can be a pain to work with but if you soak it in a sink or tub of real hot water it gets more pliable and you can shape it as you need. Regular PVC cement is all you need to secure it.
Now, the Flex will reduce vibration but even this will create some noise if it lays on the top of the tank once it gets to the returns. Do you have bulkheads for the returns? Id so this is the best bet. If not you can use a small piece of foam under a contact point or my favorite is the really thick and squishy mouse pads cut to size and doubled up. I also use these under my
external pumps to stop vibration noises from travelling through the stand!
If you can, get some pics form all sides so we can get a better idea of what you need to do! Feel free to PM me with any other questions. Ill be going to bed in a bit but will be back this afternoon (I work nights)
HTH
Robert
