Yellowed plastics on old Sundance Spa

[Krulligo]

I moved into a house about 2.5 years ago that has an old Sundance Altamar Spa (year 2000). After some minor repairs such as a leak near one of the pumps, and a few O-rings replaced to get some air control jets working and fixing up a leak in the diverter valve, I have gotten the jet running to a point that I don't suspect anymore leaks, and all functions of the spa are working. Overall, the spa shell is in great shape. I just have 1 question. Most of the gray plastic pieces such as the weir and control knobs have discolored to a yellow (see picture). Is there anyway to restore this back to original grey color?

I am currently trying to soak the parts in Hydrogen peroxide and leaving out in the sun to bleach. So far the results are looking really good and the yellowing in the plastics is nearly gone. My question is though, will this last? Or will putting the pieces back into the spa turn it back yellow in a matter of days or weeks? I use bromine as sanitizer and the spa has an ozonator. 

Thanks in advance for your input.

 

[cranbiz]

Can't answer your question but on the ozonator, if you have not replaced it, it's not doing anything.

They have a finite life,  usually 3 years so while it might make bubbles, you are not treating the water.

[Krulligo]

5 hours ago, cranbiz said:

Can't answer your question but on the ozonator, if you have not replaced it, it's not doing anything.

They have a finite life,  usually 3 years so while it might make bubbles, you are not treating the water.

Thanks for your input. Yea I am aware that they have a finite life and mine may actually not be doing anything. However, I do still smell the fruity/acrid smell for a split second when I open up my spa cover. Would this indicate that it is still working? I am not sure but the ozonator might have been a recent addition or a replacement before we bought that house.

 

[ratchett]

On 6/17/2022 at 4:38 PM, Krulligo said:

I am currently trying to soak the parts in Hydrogen peroxide and leaving out in the sun to bleach. So far the results are looking really good and the yellowing in the plastics is nearly gone.

Lol, I love that trick - it's like magic how effective this works. Takes some effort but the results are impressive - I've seen people do that often with old video game systems.

 

On 6/17/2022 at 4:38 PM, Krulligo said:

My question is though, will this last? Or will putting the pieces back into the spa turn it back yellow in a matter of days or weeks?

This yellowing happens thanks to a flame retardant in the older ABS plastics (bromine!). When exposed to UV light, those bromine molecules can destabilize and leech through to the surface, causing the plastic to turn yellow (or even brown if left long enough).

On 6/17/2022 at 4:38 PM, Krulligo said:

My question is though, will this last? Or will putting the pieces back into the spa turn it back yellow in a matter of days or weeks?

It isn’t permanent, unfortunately, since there are still free bromides deep in the plastic that can re-surface a few years later. Additionally some people think the hydrogen peroxide process makes the plastic more brittle and fragile.

18 hours ago, Krulligo said:

However, I do still smell the fruity/acrid smell for a split second when I open up my spa cover. Would this indicate that it is still working?

Odor is not a good indication of the presence of ozone - I believe the only way to really test the unit is to install a tester to the output from the ozonator which changes color in the presence of ozone or something like that (it's not the easiest thing to test in water).   There may be an easier way to test for ozone in the water, but I haven't seen anything from my quick searches.    If you can access the ozonator module, there may be a manufacturing date on it, then you can do the monster math and figure out if it's new enough to still be operational. 

Alternatively, I have heard some people mention older spas would trip the breaker when the ozonator failed (the solution was to unplug or replace the ozonator and the system would stop tripping the breaker), but I don't know if that applies to all spas and all ozonator units.

 

 

[Krulligo]

2 hours ago, ratchett said:

 

Thanks ratchett, all that information if very helpful. However, I still don't understand how this happened since it's the UV from the sun that causes this and the tub is almost always covered (unless the previous owners had the tub uncovered for extended periods of time and the sun just did a number on the plastics).

Anyway the peroxide + UV treatment is doing wonders and I got all the knobs, etc to be gray. Just finishing up with the 3 suction covers which seem to be taking a bit longer possibly do to being submerged in water (there was also some calcium buildup on them that I needed to remove before the bleaching process). So far they are coming along nicely.

I was going to do the Weir assembly but after taking it off and closer inspection, there are a few areas that have cracked, and there is quite a bit of calcium buildup, so I ended up ordering a replacement (should arrive in 2-3 weeks). I can't believe that Sundance still carries most of the parts for the 20+ year old spa. Anyway, will reply with pics of when it's complete.

[ratchett]

2 hours ago, Krulligo said:

Thanks ratchett, all that information if very helpful. However, I still don't understand how this happened since it's the UV from the sun that causes this and the tub is almost always covered (unless the previous owners had the tub uncovered for extended periods of time and the sun just did a number on the plastics).

Maybe it's due to the exposure from high levels of the bromine in the water which is yellowing the components instead of the UV.  I guess time will tell if the yellow first or if the tub wears out completely haha.

There are still a few older spas from 2-3 decades ago running strong to this day.  Spas have the best lifespan when left with water and filled/balanced/maintained as needed.   You might get another 5-10+ years out of that sucker with proper care

[Krulligo]

1 hour ago, ratchett said:

Maybe it's due to the exposure from high levels of the bromine in the water which is yellowing the components instead of the UV.  I guess time will tell if the yellow first or if the tub wears out completely haha.

There are still a few older spas from 2-3 decades ago running strong to this day.  Spas have the best lifespan when left with water and filled/balanced/maintained as needed.   You might get another 5-10+ years out of that sucker with proper care

Hmm. That might explain the weir and suction covers which are in the water but not so much all the knobs yellowing above the water line. Even for the weir there are sections of it that are not submerged but the entire weir seemed to have yellowed at the same rate. So not sure if being exposed to bromine in the water is the issue of the plastics yellowing. It might just be how the plastics degrade overtime but who knows. 

 

Anyway I hope the tub does last several more years.  I have heard really good stories with older Sundance and them lasting. It is now in a state were it is fully operating with no apparent water major leaks. I guess time will tell but will keep the water healthy and balanced. I do know that for one of the pumps there is a very small dribble leak out of the pump shaft seal but it's like 1 drop every few minutes so I am not bothered by it. If it gets worse I will have to repair it but looks like replacing a shaft seal is pretty straight forward.