[SantaMonica]

Related to salt creep, is corrosion creep. Because the metal case of the bolt-on lights is aluminum, it can corrode slowly (even in freshwater) where the seal is located, especially at the top of the light where water splashes onto it. So even a seal that is designed and assembled correctly can be pushed sideways by corrosion creep, and eventually the seal will not be sealed anymore. And if it’s on the top of the light, water can now drain directly down onto the 240/120 volt electronics inside, and you won’t see it because the corrosion is on the inside of the seal area. A stainless steel case would prevent this, but low cost metal-case lights are never stainless. Stainless enclosures are used in underwater 240/120 volt pool lighting, but those lights start at $100 each. Here is a pool accent light with a single 3 watt LED inside, and it is $40; note how much stainless steel is needed to protect it (see attached photo).

The best way to slow down corrosion is during disassembly inspection: coat both sides of the metal case (where they touch together) with grease or petroleum jelly, and re-insert the seal, and re-assemble. Ongoing disassembly and inspection every 6 months is advisable. Unfortunately, each month that goes by will allow more salt and corrosion creep to occur, and the seal will only get worse, not better. And, just like the Chinese do, you might actually mess up a seal during re-assembly, which was fine before you took it apart. So be careful.

Interestingly, most commercial scrubber builders use absolutely no metal in their main boxes which hold the algae growth, because of course the metal would corrode. There are many low cost metal boxes that could be used, which would not crack during shipping like acrylic/perspex does, but builders instead take the time to hand-construct boxes out of acrylic/perspex so that corrosion will not be an issue. So why then do they allow metal on the lights (the most important area for safety) if they know it will corrode?

The reason again is simple: Cost. Just $5 to $8 each, including shipping from China. But the Chinese know that if someone is injured because of these lights, nobody will be going to China to sue them. So the Chinese have absolutely no need to make things safer. It’s up to the DIY person to check each light (by taking it apart), and it’s up to each commercial scrubber maker to request UL certification, non-metal construction, low voltage operation, and hermetically sealed enclosures.

It's my opinion that all of the low cost metal-case lights are made in China, even if they have been relabeled to look otherwise. I've spent hundreds of hours trying to find lights (and other parts) in the USA, only to be directed to China every time. The cost of the metal castings for the case alone would be $10 or $20 each, if made in the USA. And the labor to assemble the electronic and other parts would be another $30 at least. So manufacturing in the USA is not an option for these types of lights, and if they say “Made In USA” you should assume this is not true. This was yet another reason for us to abandon these metal lights (and their internal electronics design). But even if the bolt-on metal Chinese lights were made in the USA, and even if they were UL certified, you still have the problem of the electronics enclosure not being hermetically sealed. So if water, or steam, or salt creep gets inside, and you touch the metal case, it’s not going to matter who made it, or who certified it, or what the warranty is. The 240/120 volts should be 2 meters away from the splashing and salt creep (see attached photo).