Spa flex not safe for potable water?

keithIHS · Aug 15, 2020

I was planning to plumb drains and returns with spa flex, but then I saw this at https://flexpvc.com/Guides/FlexHose.shtml under "Description":
"Same Size as Sch 40 PVC pipe, Available in White, black or gray. White is NSF 51 rated (but not for potable water) Our main product."
Another website mentioned that the potable water standard is NSF 61, not 51, so spa flex is OK for food, but not drinking water. I know a lot of people use it, but are we sure it's safe for a reef tank? Any long term success with spa flex out there? Appreciate your thoughts. Thanks.

CK00020 · Aug 15, 2020

I don’t think it can handle the pressure of a water supply system, it’s fine to drink from but not suitable to use for supply piping in a house

laverda · Aug 15, 2020

I have used it for 20 years with out an issue that I am aware off. I currently am using super flex or ultra flex, depending on where you get it. I have been using it for probably 15 years for water changes and 5 years for permanent plumbing. It is much more flexible than spa flex. It is a bit harder to find and only available in black as far as I know. It glues easily and is very tough. I accidentally parked my truck on top of my water change 50’ super flex once with over 100 gallons of water in the back and it only slightly deformed it.

CK00020 · Aug 15, 2020

It’s fine for any tank stuff, just don’t put 100 psi hot water through it

WVNed · Aug 15, 2020

I built my last system with it. No leaks and no 2 headed fish after a year.

keithIHS · Aug 15, 2020

@CK00020, I saw the pressure restriction, but I think NSF-61 is addressing chemical contamination. For example, Norwesco tanks, some of them at least, are NSF-61 certified, but they can't take the pressure.
@laverda, The same website I gave above (flexpvc.com) says their FlexPVC® is also formerly known as Ultra Flex, and it's available in black, white, grey, and clear white (translucent). BTW, it says the white is NSF-51, and by implication the black is not, but based on your and others' experience, I'd say good to go.

mtfish · Aug 15, 2020

My understanding is that it could produce an off-taste for drinking why it is not rated for potable. No problem for a fish tank.

ca1ore · Aug 15, 2020

I have been using flex pvc on my reef tanks for the last 7 years .... both on drains and on pressured returns. I will use DWV fittings on drains, but full depth shoulder fittings on returns - that’s my only ‘concession’ to higher pressure. The next time I have any kind of problem will be the first time. If you fully read the FAQ linked in the OP, I think you will conclude (as I did) that flex is just fine to use.

92Miata · Aug 15, 2020

Nsf61 requires testing from pH5 up to pH10. There's all sorts of ways to fail those tests that aren't relevant to a reef tank

robbyg · Aug 16, 2020

keithIHS said:
I was planning to plumb drains and returns with spa flex, but then I saw this at https://flexpvc.com/Guides/FlexHose.shtml under "Description":
"Same Size as Sch 40 PVC pipe, Available in White, black or gray. White is NSF 51 rated (but not for potable water) Our main product."
Another website mentioned that the potable water standard is NSF 61, not 51, so spa flex is OK for food, but not drinking water. I know a lot of people use it, but are we sure it's safe for a reef tank? Any long term success with spa flex out there? Appreciate your thoughts. Thanks.

My drains and returns have been using Spa Flex for 15 years . No problems at all with the tanks inhabitants at all. The Joint have never leaked so it’s fine in my opinion.