I'll be using a pump on this one. Probably a Maxijet750 with reduced impellers to slow the flow a bit. With the design of my new sump, I'll only be replenishing about .3 gallons everytime the RO unit kicks on, so my earlier concerns of overdosing shouldn't be an issue, knock on wood of course
Tap Plastics in Bellevue is a good source . I have been there a few times and always found what I needed, ask for Rodney he has a saltwater tank. If you do talk with him bring up the club again, I mentioned it to him last time I was there but that was a few months ago. Phone number for Taps is 425-861-0940 in case you want to call first and see if they have what you need.
I may have some 4" diameter clear, thick 1/4" wall section of tube about 3-4 foot long......
I'll have to dig around in my shop for it, or I've got 2-3 old skimmers that might work out for you too. I've got a Red Sea Berlin and another taller skimmer air-stone style skimmer with a nice big stable base.
I need some that has the same OD as 4" PVC. I'm not sure exactly what that dimension is, though. I'm using 4" PVC couplers and what not in the construction. If you've got some, I'd be more than happy to take it off your hands for you