PVC is very inexpensive an dI suspect the "thin wall stuff" is really for larger sizes.

PVC fittings that are compatible with SCH40 pipes.

PVC is very inexpensive an dI suspect the "thin wall stuff" is really for larger sizes.

Yes indeed, I'm trying to build a HSA using those 4" "Tee" white thin-wall-sewage-PVC parts. 4" Tee in Sch40 PVC is too big for my sump. I've used the gray conduit for standoffs of eggcrate, and standoffs in my sump. Although, I don't thing the conduit (for plumbing proposes) is worth the aggravation.

The reason for these grey electrical PVC fittings is that HomeDepot has a lot of fittings for it, and they are size-compatible with The only really detrimental plastic pipe is ABS (black)

I have read some of your news group-comment on the usage of PVC pipe in reef aquarium. In your professional opinion, do you recommend the use of white-thin-wall PVC pipe marked with "sewage only" that are available in HomeDepot?

The only really detrimental plastic pipe is ABS (black) Anything PVC should be fine. PVC is very inexpensive an dI suspect the "thin wall stuff" is really for larger sizes. Typically in a reef setting the largest you would use is 1.5" So my recommendation would be to stick with pipe of known quality e.g. PVC

Also, how about the electrical conduit PVC pipe and fittings? I've used the gray conduit for standoffs of eggcrate, and standoffs in my sump. Although, I don't thing the conduit (for plumbing proposes) is worth the aggravation. I understand most reefers use SCH40 white/grey parts.

The reason for it is they are easier to acquire :)

Well my advise to use all PVC, Its cheap enough and you also have the piece of mind in knowing that you're not using something that *might* have negative effects