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View Full Version : Anybody ever use PEX to plumb a reef?


ejmeier
09/23/2006, 07:29 PM
Thinking about using PEX connectors/pipe to plumb my current skimmer. If things work well, I think I may plumb any/all future tanks with this stuff.

BTW - In case anyone was wondering, PEX is basically like John Guest fittings/tubing, only in bigger sizes. Well, it is more than that, but what I am planning on using is the plastic quick-connect fittings and tubing.

http://www.doityourself.com/icat/pexconnect

The fittings definitely cost more than PVC, but you use a lot less of them because the PEX tubing is flexible (basically PE tubing) so you don't need as many elbows, etc.

Seems like it would be a good way to hook up small/medium sized pumps instead of vinyl tubing or flex PVC. And plus, with the quick disconnects, you wouldn't need to use any unions. (Probably.) I'll have to wait and see. ;)

mrwizerd
09/23/2006, 10:12 PM
You know for a smaller tank that wasnt pumping huge ammounts of water thru it. But you still could put a fair ammount of water thru 3/4 inch tubing. It would be very intresting thats for sure.

xtrstangx
09/23/2006, 10:22 PM
I used Pex pipe to cover up some allthread when I hung my VHOs.. does that count? :D

bbeck4x4
09/24/2006, 08:27 AM
what about the connectors, they are copper I belive.

mrwizerd
09/24/2006, 11:23 AM
Nah, there are plastic ones. Quick fit ones... lots of differnt ones.

ex82nd
09/24/2006, 12:52 PM
Most pex fittings are brass.The quick connects are plastic.You can also get pex in bigger size than 3/4.

H20ENG
09/26/2006, 07:11 PM
I'm sure hes talking about the Watts JG style connectors. My only thoughts are the size limitations. I've only seen it up to 3/4" locally, and even then its $$$. Cool for a little setup though.

aaronpentz
09/26/2006, 09:56 PM
Even the plastic fittings have steel grippers in side. Just make sure that if they are wetted parts that its stainless. Think of them as the chineese finger trap of the plumbing world.

ejmeier
09/27/2006, 11:27 AM
Well, I used the 1/2" PEX fittings on my skimmer waste collector, and they seem to be working great.

I used 1/2" instead of 3/4" because the fittings were insanely expensive. (It was about $4 per 1/2" fitting, and I used two...) On the plus side, the pex tubing itself is quite cheap, about the same as regular pvc.

But, 3/4" was the biggest I could find locally, but I know there are 1" fittings available too. One of the companies that makes those fittings is called "SeaTech" which I think is owned by Watts. They even make black metric sizes, so it could look more "professional" if you wanted. I just used the white stuff I bought locally.

EDIT: Here's their site...

http://www.seatechinc.com/

billy_bob76114
09/27/2006, 12:13 PM
quick fittings and pex fittings are 2 totally different things. To use the pex fittings you would have to get the tool to connect it. The tool is very expensive. I also dont think the grips on the watts seatek fittings are stainless. I have a bunch of them in my stock now and it sure dosent look like stainless. I will ley yall know on that though. I can deff. see pex being used on tanks though. I am really considering it on my next tanks I am working on.

ejmeier
09/27/2006, 03:21 PM
I thought PEX was just an acronym that stood for crosslinked (X) Polyethylene(PE). Its the tubing thats PEX, so technically any fitting that is meant for PEX tubing can be called PEX fittings.

Anyway, I'm not sure on the kind of metal that is used for the ring, I know most John Guest fittings use stainless for the ring, but who knows. Anyway, isn't the metal behind the seal? Does water ever even touch beyond the seal? (Assuming it is plumbed externally.)

H20ENG
09/27/2006, 04:17 PM
I hear this argument a lot- and ej is right. The tubing is PEX, and there are a hundred different ways to connect them.
The grippers are a non issue unless its submerged.

Sparkss
12/06/2006, 01:40 PM
what about any implications to submerging a coil of PEX in a sump to use as a heat exchanger ? The end/fitting would all be out of the water and the liquid in the pex would never contact the tank water (so the fittings wouldn't really matter). I am more concerned with any possible leeching from the pex submerged in the sump. Since pex is (if I recall) rated for potable water there shouldn't be any issue, but I just wanted to be sure that there isn't any chance of contamination. Any thoughts or info on the topic ?

douggiestyle
12/06/2006, 04:57 PM
lowes has pex and all the fittings including the jg style fittings. i am in a process and plan on using some of the pex. the 1" pex tube at lowes was about $1 a foot and came in 50' rolls.

i am planing on using it for the return from sump to tank as well as an automatic water changing system

MinibowMatt
12/06/2006, 06:00 PM
Sparxx- you need to know what the thermal properties of pex are? If it is going to be used for a heat exchanger it should be very thermally conductive. Most plastics are insulators..

Sparkss
12/06/2006, 06:42 PM
<a href=showthread.php?s=&postid=8695170#post8695170 target=_blank>Originally posted</a> by MinibowMatt
Sparxx- you need to know what the thermal properties of pex are? If it is going to be used for a heat exchanger it should be very thermally conductive. Most plastics are insulators..

Pex is used in radiant, in floor heating systems, so I feel confident that, at least in the heat exchange regard, we will be fine. Thanks :)

Sparkss
12/06/2006, 06:45 PM
<a href=showthread.php?s=&postid=8694700#post8694700 target=_blank>Originally posted</a> by douggiestyle
lowes has pex and all the fittings including the jg style fittings. i am in a process and plan on using some of the pex. the 1" pex tube at lowes was about $1 a foot and came in 50' rolls.

i am planing on using it for the return from sump to tank as well as an automatic water changing system

Good to know, thanks. That is not too far off of what it runs online. A 300' roll of 1/2" runs around $130 + shipping (and 1/2" is the most commonly used size for radiant heating applications, if I remember what I read online). Taking shipping charges and pipe size differences it doesn't seem that Lowes is that far off (which is a bit odd.. guess we need to price check a few more online vendors !!! :)).

douggiestyle
12/06/2006, 11:31 PM
<a href=showthread.php?s=&postid=8695468#post8695468 target=_blank>Originally posted</a> by Sparkss
Pex is used in radiant, in floor heating systems, so I feel confident that, at least in the heat exchange regard, we will be fine. Thanks :)

that is a totally different aplication. the reason is you have this pex imbedded in bad heat conductors. so it doesnt matter how conductive the pex is. also large amounts are coiled beneath the floor to make up for this.

keep in mind that a six foot metal base board radiator will heat the same amount of space that around 100 feet of pex tubing radiant floor system will.

so using it as an exchager in the sump wouldnt work unless large amounts of the pex was utilized.

Sparkss
12/07/2006, 12:05 AM
I have seen layouts of in floor radiant heeting, and the rows are spaced 12" apart. As for large amounts, as I stated we plan to use approx 150' in each of our sumps, so by your statement that would be equivalent to 9' of a metal radiator (then again we aren't trying to heat through a concrete slab either). That seems like plenty to heat our tank, but then again we won't know for sure until we get it up and running.

douggiestyle
12/07/2006, 12:27 AM
<a href=showthread.php?s=&postid=8697645#post8697645 target=_blank>Originally posted</a> by Sparkss
I have seen layouts of in floor radiant heeting, and the rows are spaced 12" apart. As for large amounts, as I stated we plan to use approx 150' in each of our sumps, so by your statement that would be equivalent to 9' of a metal radiator (then again we aren't trying to heat through a concrete slab either). That seems like plenty to heat our tank, but then again we won't know for sure until we get it up and running.

NTIM, i dont see anywhere in this thread where you mention that you are using 150' of pex to heat your tank.

Sparkss
12/07/2006, 08:46 AM
oops, I did in a different thread, my mistake. Sorry for the confusion. Yes, we were planning to buy a 300' roll of 1/2" or 3/4" Pex and splitting it between the 2 of us.

douggiestyle
12/07/2006, 10:06 AM
its hard to say whether it will work as needed. three things will be the major deciding factors.
1. the size of the tank
2. how much increase or decrease needed in the tank
3. the temp in the pex

Sparkss
12/07/2006, 10:41 AM
1. Total water volume 500g, give or take (750 - 850g in the other persons tank)

2. Right now I see about a 5 degree drop at night (when one of my elec heaters failed)

3. Targeting 120 - 140 degrees, based on the heater capability (which is higher than that) and that the water coming back into the heater needs to have a 40 degree drop, so with a 78 - 80 degree tank, 120 would be the min setting on the heater.


We already know that we might need to go to a longer length of pex, that is a small consideration as we both have the room in our sumps for that, it is more a matter of trying to utilize natural gas to heat our tanks versus electricity as out here in Ca electricity is very expensive. Setups running with a titanium heat exchanger run 2 to 3 times as much for the initial setup as this planned setup does, and have other challenges to over come (like the draw down on the circulating liquid before it re-enters the boiler/heater, and so forth) The longer run(s) of pex help to meet those requirements (hopefully).