• Welcome to Overclockers Forums! Join us to reply in threads, receive reduced ads, and to customize your site experience!

Eheim 1250 1/2" ??

Overclockers is supported by our readers. When you click a link to make a purchase, we may earn a commission. Learn More.


Oct 25, 2003
Houston TX
Which adapter do I need for inlet of eheim 1250?

I'm trying to build 1/2" sys but only outlet seems to be 1/2" compatible...How did you guys solve this problem?



Nov 22, 2001
According to eheim's own specs;

Inlet (suction side) = 3/4"
Outlet (pressure) = 1/2"

Though I can tell you as an owner of one, that the outlet is smaller than 1/2" once you adda barb, and the inlet is just over 1/2". I use 3/8" silicon tubing and it fits very well on the outlet (perfectly infact, 1/2" my arse), and I've managed to stretch it over the inlet. It was a struggle, but doable with patience.

If you're gunna use 1/2" tubing, it'll fit nicely on the inlet, but will probably have to be hose clamped to the outlet.

*counter edit* I really don't care how angered you are, if you circumvent the swear filter again you will be banned.


Give me a break Senior
Jul 12, 2001
Leggysoe, just boil some water and hold the ned of the hose you want to put on the inlet in the boiling/boiled water for a minute or two, that'll soften it up and you can easily stretch it over the inlet barb. The problem you'll probably have with wanting to go all 1/2" hose is the outlet, it will be a bit of a loose fit so you'll definitely need to put a clamp on it.


Oct 14, 2002
Bensenville, Illinois
What he said about boiling and clamping... I just finished assembling home made sys with 1250 and 1/2 inch tubing. Just use the stock plastic barbs that come with the pump, avoid kinks and tight turns, and your flow will be just great. I was going to put new and bigger barbs on but testing the pump stock showed excellent flow, so I abandoned that bright idea for now. If you do put new ones on, be sure that the inside diameter of the inlet is at least 1/8 inch larger than the ID of the outlet.