Does shape of return matter?

[mrm1682]

Pool was built 3 years ago and on the sundeck and deep end bench they installed these returns that spin. After some time they get stuck and the pool builder replaced them once as a courtesy but it happened again. I put in regular eyeballs but after doing so, pressure is up about 1-2 psi. I’ve read that these spinning ones frequently wear out and stop spinning so better to use the regular eyeballs…but isn’t it a problem that the pressure goes up like that? Am I better off just replacing the rotating ones?

For reference, gray one below is the rotating one and the other one is a standard eyeball that I have in all the returns now.

 

[AQUA~HOLICS]

The rise in pressure is due to the friction loss from the water traveling through a smaller object being the different jet.
It’s been my experience that the less moving parts in a pool the better.

 

[mas985]

These are normally used for spa jets not for pool returns:

These come in different sizes and the one you are showing is smaller than what it normally used for pool return which is why the pressure is higher. If you get one with a larger hole, the velocity and pressure drops:

 

[mrm1682]

It’s the opposite actually. With the regular returns in pressure went up. With the spa return in, pressure was lower. Couldn’t figure it out myself either which is why I asked. I’ve never measured the hole before but do they actually come in different sizes?

When I had the pool built I asked him why he put those spinning spa returns in a pool and he said it’s just in the areas where you’re more likely to sit…hence just the sundeck and deep end bench.

 

[mas985]

I’ve never measured the hole before but do they actually come in different sizes?

Yes, you can usually get them in 1/2", 3/4", 1" and even sometimes 3/8" depending on the manufacture.

There is a plus to the smaller sizes. Even though the pressure goes up and flow rates down, the exit velocity is higher so the return reaches further and if it is over steps or a shelf, it can help keep it clean.

But if you would rather have a larger size, you can always drill out the hole.

When I had the pool built I asked him why he put those spinning spa returns in a pool and he said it’s just in the areas where you’re more likely to sit…hence just the sundeck and deep end bench.

Without a venturi, it really isn't much like a spa jet.

 

[mrm1682]

This seems way more complicated than it needs to be The joys of having a pool!

 

[DavidArmenB]

Smaller holes cause higher pressure. The older one has two holes, the regular eyeball has one hole. If the new eyeball hole size is the same size as one of the holes of the old one, that’s a reduction of the area by two, which will increase back-pressure.

 

[mrm1682]

The older one has one hole in the back that spirals out as two holes on the surface which allows it to spin. It’s supposed to be for spas but they use them on the sundeck and deep end bench where people may be sitting. Here’s a pic of the back where you can see two exit holes.

Either way, I guess it’s still a reduction in effective size which results in slightly higher pressure.