Need help hard plumbing Fluval SP4 return pump

[nim6us]

Hey all! So I've got all my equipment, all my pipe, and I sat down to dry fit everything today. Unfortunately I've got stuck at step one... ;Dead

I went to insert my 25mm pipe into the 25mm return on the pump and it's not tight at all, it's VERY loose. It would take half a roll of pipe tape to make it snug. I verified on the Fluval website and it says the diameter is 25mm. The pipe is snug with all my other fittings and valves, so I think I'm missing something.

I have an idea of how to get it done, but I wanted to check to see if someone with experience could verify. The problem is I think this return pump wasn't designed for hard plumbing and more meant with barbed ends and tubing. I've got a union that may work though; here's what I'm working with.

Here's the pump and the barb fittings

Here's the the 25mm pipe inserted in the top, the blue arrow shows all the extra space

This is a close up of the barb fittings showing the 20mm and 25mm gradients

Now if I screw the barb onto the pump I can slide the end of a union on. I hear a click, it feels snug, but as the 25mm area is barbed will the PVC cement fill in the spaces enough to make a tight seal? Also should I clip off the 20mm bit that's protruding from the top where the blue arrow is pointing?

Finally this is what it all looks like with the union screwed together

So is this the right solution or am I way off base? I'm very open to suggestions

 

[ca1ore]

Not sure I am entirely following the logic here. The Fluval SP series use NPT threads (I haven't had the SP4, but I did run the SP2 for a while), so just screw a 1" union onto the male ends of the pump.

 

[gcarroll]

I always recommend to people to use about 10 - 12" of silicone hose before the hard plumbing to get rid of any vibration that may be caused by the pump. something like this:

 

[nim6us]

Not sure I am entirely following the logic here. The Fluval SP series use NPT threads (I haven't had the SP4, but I did run the SP2 for a while), so just screw a 1" union onto the male ends of the pump.

Sorry CA my first time attempting any plumbing. My unions are slip fit, are you saying if I get threaded unions I can just ditch the barb all together and screw it right into the top of the return pump?

 

[ca1ore]

No worries, we were all there at one point LOL. Yeah, If you get a threaded 1" union (the white ones at HD will do just fine; assuming you are in the US), it will thread right onto the black male ends of the pump. Ideally you would want to use thread sealant instead of tape, though truth be told I just always use tape. If you do use tape, use it sparingly so as not to crack the union.

 

[nim6us]

I always recommend to people to use about 10 - 12" of silicone hose before the hard plumbing to get rid of any vibration that may be caused by the pump.

If I decide to go this route, obviously the pump has the barb attachment already built in, however what would I need to attached to my PVC pipe? I found a couple on Google, but they don't look like they glue in, they look like they just push in. Can you offer a link so I can be certain?

 

[nim6us]

Nevermind, sorted it all out, thanks for all the help guys. I was just trying to force a square peg into a round hole