Hi there, so I read a lot of these articles, and I settled on a HiBlow 120LL for my aeration rig. I read a couple posts where Journeyman had talked about using 3/4-in PEX out to a diffuser.

I bought the PEX and some 3/4-in fittings, but the PEX is way more rigid than I expected, and I'll be damned if I can push the barbed fittings into the pipe. It's cold out, so I brought the PEX in last night to warm up, but it's been inside for 24 hours now, and it still feels like I'm trying to push a barbed fitting into a piece of PVC. Is it supposed to be this rigid? Am I supposed to heat it before trying to push the fitting on?

THANKS!

Theres a tool to expand the end. Look up pex expander.

No No No... Not PEX to the pump. Too stiff : )

Go to hardware store and get some flexible clear tubing with the reinforcement webbing built in.
Then you will adapt from Hose to PEX through a 3/4" tee. The reason for a Tee and not a union is, this is a good place to put a gauge.

So, the list would be;
1. 3/4" hose
2. 3/4" tee
3. Hose barb 3/4"npt - 3/4" hose
4. PEX adapter 3/4"npt - 3/4" PEX
5. Bushing reducer 3/4" - 1/4"
6. Pressure gauge 15psi 1/4"npt

Also, if you are running multiple diffusers, you will want to balance the flow to them.
This is best done with Gate Valves right where you divide the lines.

Congrats on your new project! You're off to a good start.
Report back on how it works for you.

Thank you! I had already bought a 3/4" tee, two 12" Matala diffusers, and barbed fittings to connect the PEX to the discs. I got an expander tool, so it's set up and running fine

However, the roll Pex is holding it's rolled shape, so it looks like I have two loch ness monsters with all these coils rising out of the water. I don't want to weigh it down, I wish I had gone with weighted hose instead.

If I switch to weighted hose, should I get 3/4" diameter in that? Or can I use 5/8"?

5/8" will be plenty. You can use the grey 1/2" barbed fittings that you find in the local big box hardware/lumber stores. The self weighted airline you can use regular PVC glue to glue the barbed fitting to the hose, or just use hose clamps (preferably stainless) or go the belt and suspenders route and glue/hose clamp. Be forewarned, if you use the glue, if you have to take it apart you will be cutting it and throwing away the barbed fittings with a part of the hose still attached.

Don't feel bad, been there, done that with the non-weighted air line. I weighted mine, then the zip ties broke and it got tangled in fishing line, and was a general PITA. Re-spent $$ to get the weighted airline and kicked myself for not doing it in the first place.

LOL... Fear not! Save your money, use what you got.

Getting the slinky look out is easy. Roll it out flat on your lawn and leave it in the sun for an hour, it'll stay flat.
Weighing it down is easy too and definitely necessary. You'll need 3lbs of weight for every 10 feet of length. There's lots of options for weight.

Here's a couple ideas;
Get a bag of concrete and make softball size balls around your PEX about 6 feet apart, let dry in the shade.
Get some bricks, the kind with the 3 holes in them and slide them down your line as you paddle out.
Find a guy like me, that has perfect size steel doughnuts : )

I used #4 rebar and zip ties.....Still a PITA. The weighted airline is 0.5# per linear foot. Plus it has a 15 year warranty.