I am using Tygon tubing which measures 1/2" ID. I am getting leaks on the output barb. It has been a real pain. I haven't had any issues with any other connections.

Note: Today was the first day I tested it. I am still a work in process. ...Rich

I think I know what you mean now,if its what I think you mean its for when you use this pump in a pond to make it a fountain.

Nope. I mean part numbers 7438200 and 7438510. See the enclosed link. http://www.dtekcustoms.com/product.asp?3=64

...Rich

Yes the 200 part is the barbed part the 510 is the part for the fountain or whatever.

The 510 part measures 1/2" ID or 5/8" OD at the threaded end. The other end is bigger.

The Eheim barb IS actualy a 1/2 inch barb. The dangerden Maze3's 1/2inch barb measures the same. 1/2inch barbs are'nt measured by the inner diametre :) . I thought the same thing when I saw my 1250 first off :) ...

I brought a 16mm (5/8) barb to go on there instead. It fit's because the outlet uses 3/8BSP thread instead of 1/4BSP thread that 1/2 water blocks use. The 5/8 barb made no difference to my temps though :shrug: ...

Where did you purchase the 5/8 barb? Thanks, ...Rich

THe barbs are designed to go into tubing. So a 1/2" barb fits into 1/2"ID tubing making its OD 1/2". The barb's walls have some thickness, so that means that the ID of the barb is less (yes a stock 1/2" hosebarb is close to 3/8" ID). That's why many of us either:

• Use 5/8" hosebarbs (their inside diameter is right at 1/2" and you can still get tygon and clearflex or silicone over them nice and snugly)
  
  Use copper pipe fittings instead of barbs for much nicer IDs
  
  Use a drill press and open up our 1/2" hose barbs more for higher flow.

To FURTHER add to the confusion, Eheim pumps are european, so the barbs aren't exactly 1/2" and the threads aren't NPT. I have found that a 3/8"NPT x 5/8" barb will go in ok on the 1250 outlet, but use silicone "Goop" and DON'T tighten it all the way in. You will crack the housing if you do this, especially with a brass barb but even with nylon ones. I had to JB Weld a friend of mine's pump back together the other day who had done this.

I solved my leak problem with Teflon paste, used on gas fittings, and a metal hose clamp. Apparently this problem is common when using Tygon tubing. I sent an email to D-Tek and let them know they should stock the barbs sold in UK and AU. ...Rich

pH is dead on. Remember if everything was measured by OD or ID it wouldn't be possible to fit tube over barbs.

To add to what he said, you can use 1/2 inch PVC fittings on the outlet thread just fine. I wouldn't attempt the inlet though, its some odd size. I'll see if I can dig up a link when I get home.

ahhh, now i see. thanks for the clarification. if i shouldn't attempt to fit my 1/2" tubing over the inlet, what should i do?

nah the inlet is fine (it is just under 5/8" I think). I used it forever with 1/2" silicone (ID eh?) stretched over it

is the stock eheim ready to accept 1/2" tubing? Would you happen to know about cooltechnica's ClearFlex60 1/2" tubes?

thanks

Good news from D-Tek. "Hi Rich,

You are correct the tygon is a little loose on the output barb. We can and will supply new barbs for that. Thanks for the heads up on it.

Thanks,
Danny
www.dtekcustoms.com
Ph 949-829-0067
Fax 949-829-0078"

...Rich