LED Height - unprotected?

[el aguila]

I have a DIY LED fixture that I'm getting ready to install. How high above the water surface do I need to hang the fixture if there is not any acrylic sheild installed to protect it?

[lordofthereef]

Personally I do not like the idea of an unprotected DIY array. You will have soldered contacts open to salt spray and air.

[el aguila]

Originally Posted by lordofthereef

Personally I do not like the idea of an unprotected DIY array. You will have soldered contacts open to salt spray and air.

I understand what you are saying. Many people who are placing splash gaurds on their fixtures are not totally enclosing them which means that they are exposed to salt air.

I would like to hear from some people who have had fixtures up for awhile if they can see noticeable corrosion?

Another thing that I thought about was using liquid tape on all exposed contacts/wires to protect them. Not sure how liquid tape holds up long term when exposed to salt air.

[bigrock]

I had my 144 led build about 10 inches above my tank for over 1.5 year and I didn't noticed any corrosion. No shield but I did have optics on each led. I didnt lose one led. I'm building a bigger fixture for a 300 gallon right now and I don't plan to use a shield on this one either if that helps.

[el aguila]

I was just surfing Reef LED lights.com and noticed this LED seal:

http://reefledlights.com/shop/led-seal/

Anyone have experince with this? I would not spray the optics with it.

[zero26]

I would say any less than 2 feet splash guard. Mine will be about 4" off the water and will have an oversized splash guard. Or you could order some LED Seal. If not protect your investment some way!

[VeL]

I am still in a process of building my own led array and I'm definitely going with splash shield. I don't think the salt air will be a problem though as I know people who have simillar builts for quite some time and they didn't mention anything about corrosion. Overall a really thin splashshield will affect the light by not more than 5-10%.

[der_wille_zur_macht]

Surface corrosion isn't an issue on a properly designed and built fixture. The only exposed metals are all rather resistant to corrosion (tin, lead, gold, silver) assuming you have made good materials choices (tinned wire, such that there is no bare copper, and fully tinning copper pads if there are any on the MCPCBs) and have good technique (clean the flux off your solder joints).

That really leaves two potential problems: Salt buildup from nearly microscopic spray, and real "splashes" from fish, maintenance, etc where there's a significant mass of water hitting the LEDs. The former is an issue because it can wreak havoc electrically and cause reduced output. The latter is an issue for those reasons plus the thermal shock of hitting a super hot LED with cold water.

Personally, if there are optics on the fixture and it is above 24" up, I don't use a shield and I don't think twice. Down around 18" or below I would probably start to get nervous especially if the aquarium had lots of surface agitation or boisterous fish. I would add several inches of height if there were no optics, because that means less protection for the LED itself.

That said, I have had longterm fixtures that broke those rules with no issues. I had two test fixtures a mere 3" above the water on a nano for 8 or 9 months. There wasn't a ton of surface agitation and no fish (so splashes weren't an issue). After 9 months there was no corrosion, but there was some minor salt buildup that I wiped off before retiring the components.

Originally Posted by el aguila

I was just surfing Reef LED lights.com and noticed this LED seal:

http://reefledlights.com/shop/led-seal/

Anyone have experince with this? I would not spray the optics with it.

There's a rather hotly debated thread on here regarding that product, you can get all the opinions you want there (including opinions from people who have undisclosed connections to vendors who sell it - guess whether or not they were cheering the product on!) Personally, it strikes me as unnecessary, for the reasons stated above. Even if I thought it was a good idea, I can't see paying $25 for what is essentially a can of $1.99 clear spraypaint.