# DIY - 120v Underwater Light Fixture (Ver. 1 - Using Water Filter Housing)



## Spankis

For the last few years I've been going down to the Florida keys to do some fishing with a buddy. The first time I went with my family, I came across a home with a very bright underwater mercury vapor fixture at their dock and found it quite neat. With the super clear water off the keys, it attracted fish and made for an almost aquarium effect at night hanging out by the dock - very cool. 

I had done some research on these mercury vapor lights when I got home from that first trip, and I was AMAZED at how pricey the mass produced options were, especially for someone like myself using it almost solely on vacation trips. About a week before leaving on another trip to the Keys last year, I decided to make a similar device on my own, just for fun and in a short time on a budget. 

My basic goals were:

1. 120v powered
2. Safe 
3. Small/Portable (not permanently mounted, packable on a fishing trip)
4. Less than $100 total
5. *Bright as possible given goals #1-4*

After looking around, I basically needed a waterproof and pressure rated housing of some kind, a 120v light source, and a durable waterproof power cord. 

I settled on a clear in-line water filter housing, commonly used in residential reverse osmosis water filtration, as my "waterproof fixture". Specifically I chose THIS ONE. Not only are these housings waterproof, but as a device rated for 125psi of positive pressure, I figured the negative pressure of 6-15 foot depths wouldn't be a problem either. After much deliberation, I settled on using an intermediate based CFL bulb as a light source. The brightest one I could fit in the housing ended up being a 42w (200w equivalent) Feit Electric, as seen HERE, listed at 2800 lumens. There were several others in the 300w equivalent range that very nearly worked, but they all ended up being slightly too girthy to fit the housing I bought. In addition to the housing and bulb, I bought a 50' S.O. appliance power cord, and ran it through the incoming side of the in-line filter head, and down into the clear housing portion. I bought a plug for the outgoing side of the filter head, and sealed both the plug threads and the port through which I fed the power cord with 3M 5200 marine sealant, as seen HERE. I used an ordinary pigtail lamp holder to hold the bulb, as seen HERE, though I had these laying around already. Once together I let the marine sealant cure for a week, and when I actually tested it in Florida I plugged it into a GFCI extension cord, tied an anchor to it, and sunk it to the bottom below the dock. It remained on the bottom for 9 days, untouched, being plugged in nightly for fun. 

Here are some decent pictures of the finished product, still dirty from it's trial run:

http://i180.photobucket.com/albums/x33/spankis/Underwater Light/20130727_205404_zpsad371ee3.jpg

http://i180.photobucket.com/albums/x33/spankis/Underwater Light/20130727_205343_zps15c238ac.jpg

http://i180.photobucket.com/albums/x33/spankis/Underwater Light/20130727_205326_zpsed1d8417.jpg

And here are some admittedly awful cellphone pictures of the light in around 10 feet of water:

http://i180.photobucket.com/albums/x33/spankis/Underwater Light/IMG-20121007-00076_zps72dad12f.jpg

http://i180.photobucket.com/albums/x33/spankis/Underwater Light/IMG-20121007-00071_zpsc782728a.jpg

Though quick and dirty, I consider my first attempt a success, especially considering I spent less than $60 on the whole project and the housing was bone dry after it's initial use. I'm planning on returning to the same location in the keys this October, so I'm planning on at least adding a second fixture to the cord in series. I could easily make an exact duplicate of the first one, but I'm now thinking through potentially brighter options as well. So far I'm considering a larger housing to fit a larger/brighter CFL, though the larger housing options get much more expensive quickly. As always I'd love to use an LED source of some kind, but at 120v and required 360 degree floody output I'm not sure there are many simple budget options that outshine the CFL.

Any criticism or ideas on improvement would be much appreciated! Thanks for looking.


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## yuandrew

Perhaps try some colored gels like green or blue? 

Many of the fish-attracting lights I've seen online use green fluorescent tubes and clear mercury vapor lamps are inherently blueish-green.


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