Need some help selecting the proper stainless for pool application

[ShortWallCells]

Short story, my pool is a salt-system pool. The pool water contains about 5000ppm of NaCl and the system passes current through a cell to produce Cl. After about 5 years the cell has failed, I am trying to fab up my own replacement. For first attempt I used 316L stainless, this lasted about 5-6 hours before becoming totally pitted and the hardware also stainless(bolts/nuts) failed as well. See pics. The pool is now a green/orange color. Obviously 316L is not he proper choice for the cell replacement material, I could use some suggestions please!

 

[ShortWallCells]

Would Ti be a better choice?

 

[EdStainless]

Correct, 316 will not work in seawater.

Ti is the easy option. The other possibility is to use a super-ferritic alloy like SEA-CURE for tubing and then use a 6% Mo super-austenitic (like AL-6XN) for the hardware.

What size is the tube? I might have something laying around

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Plymouth Tube

 

[ShortWallCells]

Thanks for the info Ed! I am currently using 2.25" with an inner tuber of 1.5" both 8" long, the unit could handle anything up 3" for the outter tube and the inner around 2" or so if you have some scrap laying around!

 

[strider6]

what's the operating temperature?
you said that Cl is produced in the cell (Cl2?), Cl2 is a strong oxidant and this can also increase the corrosion.
you can also consider a superduplex stainless stell (2507) which works well in water but at low-medium temperature

S

Corrosion Prevention & Corrosion Control

 

[ShortWallCells]

OP temp is from 50F up to 92F at 4000-5000ppm NaCL with the CL in the 1-3K ppm range

 

[EdStainless]

I may have some 2" tubing, and smaller stuff is easy, we make a lot of 1.25".
Sorry that I don't have anything larger.

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Plymouth Tube

 

[ShortWallCells]

Ed, can I buy about 6-12" of the 1.25" and 2" from you?

 

[EdStainless]

Let me find the pieces and then I'll get back to you.
ed

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Plymouth Tube