Rust on new light

[Sueb19]

First post, have been following TFP but never posted before.

2 weeks ago we replaced the liner in our SW IG pool and with it replaced the light. Fill water was 1/2 trucked in, 1/2 county water. Within a day, top screw started rusting. Pool store that did the install said it was due to high TA (250) from fill water. Have been working to lower PH/TA with muriatic acid, only other thing being added is CYA with a sock in front of a return.

Our previous light was also rusty but not this quick, more like 5 years or so. Light is Pentair.

Current test results - Chlorine 5, PH 7.8, TA 140, CYA 40

 

[ajw22]

Welcome to TFP.

. Within a day, top screw started rusting. Pool store that did the install said it was due to high TA (250) from fill water.

Typical Pool Store BS answer. TA does not cause metal to rust.

Our previous light was also rusty but not this quick, more like 5 years or so. Light is Pentair.

It is a low quality metal screw. Tell them to replace the screw with a brass or stainless steel screw.

 

[Sueb19]

Thank you. They are replacing the screw but not until I get the TA down. Since the rust has spread beyond the screw, suggestions for removing? Or should I leave it until they come to replace the screw so they can see it?

 

[ajw22]

What light was installed?

Are you sure it is "rust"?

Have you scrubbed it with a schotchbrite pad?

 

[Sueb19]

It’s a new Pentair LED light. I’m not positive it’s rust, it appeared right away when we filled the pool after the liner replacement/light install. At that time it was just on the screw.

I haven’t scrubbed it with anything bc I wanted the people that installed it to see what it did so they fix it.

Open to suggestions - I’m a lap swimmer so I’m in the pool with it and can look at it up close under water.

 

[Sueb19]

Update on the light. It is a Pentair intellibrite 5G LED light. I was in the pool today and wanted to check the status of the ‘rusty’ screw. As seen in the original pic I posted the rust had spread to the silver ring and I wanted to see if I could brush it off. Well, apparently that screw is rusted completely away and is the only thing that holds the light into place. It has a crevice at the bottom of the outside ring that holds it at the bottom and the screw holds it at the top. Or it did, but does no longer because when I brushed at the rust on the ring the whole light came out. The pool store sent someone over to check it out and it’s going to be like that until they get a new screw.

When the pool guy pulled on the light to show me how it all went it, I notice it’s already rusty on the portion of the light that’s out of sight. Is that normal? Really want this new liner/new light looking good for as many years as possible.

 

[1poolman1]

Update on the light. It is a Pentair intellibrite 5G LED light. I was in the pool today and wanted to check the status of the ‘rusty’ screw. As seen in the original pic I posted the rust had spread to the silver ring and I wanted to see if I could brush it off. Well, apparently that screw is rusted completely away and is the only thing that holds the light into place. It has a crevice at the bottom of the outside ring that holds it at the bottom and the screw holds it at the top. Or it did, but does no longer because when I brushed at the rust on the ring the whole light came out. The pool store sent someone over to check it out and it’s going to be like that until they get a new screw.

When the pool guy pulled on the light to show me how it all went it, I notice it’s already rusty on the portion of the light that’s out of sight. Is that normal? Really want this new liner/new light looking good for as many years as possible.

When the light was installed, most likely, the installer lost the original screw that came with it and just used a zinc-coated screw from his tool box, seen it many times.

 

[ajw22]

The Intellibrite uses a special bronze or stainless steel screw…

 

[Sueb19]

Since the pool store does not have my screw, and since I checked the Pentair site and they are already discontinued, and since the light is already starting to rust in the niche, should I just get a different light? What fits into that size niche?

 

[ajw22]

Since the pool store does not have my screw, and since I checked the Pentair site and they are already discontinued, and since the light is already starting to rust in the niche, should I just get a different light? What fits into that size niche?

The screws are available...

https://www.amazon.com/Pentair-79104800-Captive-Washer-Replacement/dp/B002NJME46

Pentair 79104800z Brass Pilot Screw With Captive Gum Washer

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Pentair Brass Pilot Screw with Captive Gum Washer - 79104800

This pilot screw is designed to use with Pentair IntelliBrite 5g white color LED pool/spa lights and also compatible with Pentair SAm Spectrum Amerlite, SAL Spectrum AquaLight, AmerQuartz, SpaBrite, HiLite, SunBrite II/SunGlow II pool and spa lights. Includes captive gum washer.

www.thepoolsupplywarehouse.com

 

[Sueb19]

Pool light update - they came out today and replaced the screw. What was left of the original screw was sheared/corroded/disintegrated in the niche and had to be removed with pliers. In reading the manual, I found this statement several times “be sure to keep the special pilot screw from this underwater light. This screw mounts and electrically grounds the housing securely to the mounting ring and wet niche. Failure to use the screw provided could create an electrical hazard, which could result in death or serious injury to pool users, installers, or others do to electrical shock.”

The first screw started rusting in the first 24 hours. Could this mean there is an issue with the electric to the light? What could eat away the screw in a matter of two weeks? Pics below. 1st pic is what is left of original screw, 2nd pic shows new pilot screw (they had to set the fixture aside to get out what was left of screw). The rust marks leave no doubt where it came from.