Stenner Pump tubing cracks

I'm looking into a Stenner and one of the options is a black UV resistant tubing, which would lead me to believe the other tubing options are not UV resistant.

Who installed the stenner pump and is the tubing clear? If so the tubes are probably just water line for a fridge and will not handle sun and chemical degradation. There is nothing wrong with this approach because it is much cheaper and depending on the run from chemical tank to pump it probably wasn't sold with enough hose. You will probably pay 3x the cost for good hose, justify how often you need to replace the hose because it will cost around $1 per foot for good hose

I don't think it's UV - I am having the same problem with UV resistant tubing and it's happening every couple of months - it's so close to the pump ferrule that I think it's the oscillations of the pump operation causing stress to the tubing and eventually cracks. The problem with mine I think is the curvature of the tubing coming from the opposite side of the inlet/outlet. So, I'm considering making a curved ferrule extension tube to take the strain off of it. Maybe I'll 3d print something. But, maybe even a spring support at that point might help relieve the stress like some high end garden hoses.

I think @darinhoustons hit it on the nose. I have had this “occasional” problem as well (maybe once a year) near the output/input ferrules where the tubing naturally loops downward and the vibrations seem to exacerbate the stresses until a leak occurs. In my pad rebuild I repositioned (turned it) my stenner so that the ferrules/tubes go straight downward, no it’s not a standard installation placement. I’m on vacation now and can’t post a more specific picture, but here is the closest I have now from previously posted pictures…so far no problems.

See the 2nd photo here:

Back from vacation so, in case there is any interest, here are a couple closer photos of my last stenner pump install to avoid the problem talked about above. So far a year+ and no issue. As I mentioned, it’s not a “standard” orientation for the pump.

I have replaced it twice now in a couple of months - the Polyurethane I'm using is sufficiently chlorine resistant for my needs, but I think it's just too brittle - I don't get much UV in my area, but the bend radius is just too much - I have almost the worst orientation for my installation I'm afraid and I really don't want to move it.

Instead of replacing it this time, for a short term solution (which might actually end up working long term) I grabbed a short piece (like 6") of soft rubber tubing (not sure of the material) I had laying around that was JUST big enough to slide over the tubing (with the help of some lube). I slide it on over the existing hole as a "patch" of sorts to seal the hole and decided it might well seal well enough to leave there - I'm watching it - but, it ALSO acts as a strain relief - I might try to 3d print something to slip over everything and have a controlled bend and engage the ferrule so the whole thing moves with the oscillations instead of just the tubing.

Work in progress.

My tubing has been connected to my pump (also a Stenner) for many years without a problem. I used the tubing that came with my IntellipH acid dispensing system, which I expect is properly rated for the acid. And I encase all tubing and wires, everywhere around my pad that might see the sun, in wire loom, like this:



That wire loom is UV rated. It cracks. And I used to use zip ties that were UV rated. They would break. As near as I can tell, "UV rated" means next to nothing. I replaced all my zip ties with stainless steel wire, and purchased a large roll of wire loom, to make it cheap to replace.

Use the proper tubing and keep it out of the sun.

It's true, the tubing from Pentair is crazy expensive:
Pentair 522384 Tubing for IntellipH Controllers Chemical Injection

@JoyfulNoise, can you recommend a resource for the OP to purchase a like product (acid and chlorine "proof") at a reasonable cost? Some sort of chemistry supply shop?

Dirk said:

It's true, the tubing from Pentair is crazy expensive:
Pentair 522384 Tubing for IntellipH Controllers Chemical Injection

Pentair 522384 Tubing for IntellipH Controllers Chemical Injection

The Pentair 522384 Tubing for IntellipH Controllers Chemical Injection is an excellent choice for your needs! Get it today at Pool Warehouse!

www.poolwarehouse.com

@JoyfulNoise, can you recommend a resource for the OP to purchase a like product (acid and chlorine "proof") at a reasonable cost? Some sort of chemistry supply shop?

Click to expand...

Here is where I bought my official Stenner tubing from last time, now 100’ for $43.


Hey @Dirk, shading the tubes is definitely a plus, but I also notice that in your configuration the ferrule/tubes are pointed down, unlike the recommended position for the stenner pump standalones which puts them horizontally (at least mine does with the “This END UP” labeling on my included bracket, haha).

jonpcar said:

Hey @Dirk, shading the tubes is definitely a plus, but I also notice that in your configuration the ferrule/tubes are pointed down, unlike the recommended position for the stenner pump standalones which puts them horizontally (at least mine does with the “This END UP” labeling on my included bracket, haha).

Click to expand...

Are you talking about the tubes leading into and out of the the pump housing? I never gave that any thought. That pump is mounted to a Pentair IntellipH, and that's how it comes. I doubt it matters much, but it would seem that coming straight down would put less stress on the tubes vs coming out horizontally. Maybe there is some other reason your Stenner needs to be oriented that way, though I can't even guess on why that might be.

PS. Pentair recommends all that tubing be replaced regularly. (And with what they charge for it, I can see why!) I've never changed mine. I suppose I should. The acid did a number on the internal tubing (the tube that the rollers squeeze). It was trashed. And I've had to replace the injector at least once, 'cause that got eaten up, too. Just FYI.

Even the parts made to be subjected to the acid eventually all succumb to it.

Dirk said:

Are you talking about the tubes leading into and out of the the pump housing?

Click to expand...

Yes…with a stand-alone stenner pump install (with your own tank), the recommended positioning is shown in the photo below. This is not a picture of my system, this is just one I grabbed from another thread. In any case, the stress over time on the red circled tubes is where the OP is having the problem…same as mine previously.

jonpcar said:

Here is where I bought my official Stenner tubing from last time, now 100’ for $43.

Click to expand...

Note that Ebay page says nothing about "acid" or "chemical." That's not to say that tubing isn't rated for acid, but it doesn't claim that.

Versus this page that does say "chemical," and a FAQ mentions something about 'an "A" rating for Muriatic Acid, 20 Baume.'

Both pages claim the same part number, "AK4010B," but the latter page doesn't call out "Stenner."

It's probably the same stuff, but "acid rated" and "chemical tubing" are the terms you're looking for.
-----

Speaking of which, note the "20 Baume" designation. That's the 31% muriatic you get from the pool stores. Sometimes the big box stores max out at 14.5%. I buy the 31%, but I never use that full strength in my tank. And Pentair recommends a 1:1 dilution with water, which is what I do.

So I would recommend to never use muriatic at full strength, but dilute it at least 1:1. That should help the parts last longer.
-----

There's another reason to dilute, too. My tank hold about 3.5 gallons. So there's never more than 1.75 gallons of 31% in there (diluted to 3.5 gallons). Should my IntellipH ever go kaflooey, and empty the entire contents into my pool (right after I fill the acid tank, of course), the most my pool would ever have to endure is 1.75 gallons of acid. Which will trash the pH for a short time, but not cause any permanent damage, and not be dangerous to swimmers.
So if any of you are connecting 15 or 30 gallon Stenner tanks to your pool, or even the 7.5 gallon, consider the consequences should your little pump get stuck on. Even worse if you're not diluting the acid. Not only the consequences to your pool and its equipment, but more importantly to you and your family and guests. Do the math.

There's a story about such an incident. A public pool, and their chlorine tank system failed and dumped all the liquid chlorine into the pool. Kids jumped in and ended up getting a trip to the hospital. So it can happen.

I like my little 3.5 gallon tank. Even at that size I only have to fill it a few times a year, so that's a fair trade and a good balance between safety vs convenience. Think it through, just because you have a big tank, doesn't mean you have to fill it up all the way.

jonpcar said:

In any case, the stress over time on the red circled tubes is where the OP is having the problem…same as mine previously.

Click to expand...

Interesting. So acid, UV, gravity and the gyrations the pump puts it through, yah, those are some harsh conditions for that little tube, for sure.

As I said, use the good stuff, keep it out of the sun, and replace it periodically. That's pretty much all you can do.

You could make a note of how long it takes to start to develop the cracks. Figure out 50-75% of that time, and set a calendar event on your phone for that time to remind you to change out the tubing with new. Being proactive with it would be better than waiting for it to fail before replacing it.