Waterproof LEDs for tank in bright room
 

JANUARY 2020 UPDATE: thanks to everyone who gave input on the project! I went with an HLG Saber light, wired up to a 90-watt driver, and am happy so far. You can see the tank build here: 72-gallon partially planted bowfront aquarium

Hi, after one of our coldest & snowiest winters in the Midwest, I've been itching to start an orchid tank.

I've spent the last week reading about lighting and attended a local class by a hydroponics grower & store owner who hated all LEDs except one $800 fixture he'd tried.

I'd really like to go with LEDs for energy efficiency & light clarity, and I'm having a hard time figuring out what would be best for my situation. I will have bright ambient light and need something waterproof so that I can have a mister.

What I'm trying to grow: Miniature orchids (TBD), bromeliads, tillandsia, and provide a winter home for my oncidium intergenerics & dendrobiums. I suspect I'll have a mix of higher- and mid- light plants so was hoping that I could place the higher light need orchids higher in the tank.

Environment: tank, likely either a 90-gallon or 75-gallon aquarium from Craigslist, in a 48" length. I want to use a MistKing mister to help keep humidity at at least 70%.

Ambient conditions: On the east wall of a southern facing room with a wall of windows on the Southern side; has bright light when the deciduous trees have dropped leaves (mid-Oct. - mid-May). The tank will only get a small ray of sunshine in late afternoon but will be placed within 7' of the windows (perpendicular). I currently have houseplants in the spot where the tank will go - a FLF with slightly etiolated growth & a happy bird of paradise.

Lights I've considered:

• PHILLIPS GREEN POWER LED PRODUCTION MODULE - This is waterproof, but not sure one would be enough light? Expensive if you need two ($260). Impressive PPF.
• Skylight Blue LED - Pro - Triple (82 CRI) - Not a lot of info on this system and CRI seems low; built for terrarium use
• Sunblaster T5 LED Conversion Lamp 4' - I have an existing single SunBlaster T5 fixture circa '09, but it wouldn't be waterproof. Not sure one bulb would be enough light. Also, it sounds like there may be some concerns with compatibility with older SB fixtures?
• SUNBLASTER LED STRIP BAR WITH REFLECTOR - Not waterproof
• 4' Active Grow 40-watt Wide Spectrum LED 2 Tube Light Fixture - Nice CRI, not waterproof
• LED 5 Row Strip Plant Grow Light - 120 Volt - High Output (SMD-2835) - Waterproof, but limited info on lighting; also, an electrical project.
• Spectral Designs 46" x 8" LED Light Strip Panel - Likely waterproof, but limited info on lights.
• HLG 65 V2 4000K Horticulture Lighting Group Quantum Board LED Grow Light Veg & Bloom 4000K - Not waterproof, maybe too much light?
• Mars ECO 300W Led Grow Light for Beginner-Mars Hydro - Not waterproof. Might be too bright.
• Mars SP-250 LED Full Spectrum Hydroponic LED Grow Light - Not waterproof. Too much light?

Can someone help point me in the right direction as to what my best options are?

Thank you!!!

I really look forward to starting my first tank and growing some new types of orchids.

P.S. I tried to link to all of the referred lighting sources to help others doing the same research, but apparently I am not able to include more than one link as a new user.

Look at lighting intended for freshwater planted aquaria. I have a pair of 3' Chinese LED strips, Zetlight brand so intended on a wire shelf unit 14" deep. They provide plenty of light for decent sized Cattleya, and are waterproof. Iirc retail was about $80 ea.

Thanks, that looks like an intriguing option!

If the tank has a glass cover, you can use all the non-waterproof ones you want above it.

I was thinking about a partial cover to allow some airflow, so if it won't diminish the lighting, that certainly makes it easier!

I love my HLG 65 for growing orchids. Super bright and I've got it covering a 3x1 space as supplemental light for my windowsill. i have 200w chinese cree cxb3590 cob fixture that I also like as well but obviously you get what you pay for when it comes to aliexpress. the 200w has optics on it so I can hang it pretty high.

the quantum boards will lose some efficiency but if you're worried about water proofing the quantum boards you can get a silicone spray to cover the diodes. they will tell you the brand to buy online or at a hardware store if you email them.

the HLG 65 will be pretty strong so you will have to hang at least 2ft by my estimation. they also sell the HLG 40 on their website which is 40 watts and and in a more linear pattern instead of a rectangle which might be more appropriate for your use.

mars are crap dont get mars hydro stuff.

This is extremely helpful, thank you! I hadn't seen the HLG 40, and two of those sound perfect for a 4' long tank. I like that they publish their photo efficiency & PPF since it helps to compare.

I read another orchid board thread about how much wattage you should have for a tank, and someone said they thought roughly 1 LED watt per tank gallon was appropriate if you have additional ambient light. So 80 watts would be pretty close if I get the 90-gallon tank.

My room's pretty bright in winter - my nobile dend is pushing two new canes out and it's 15' from the window with no additional light.

The "watt per gallon" thing is not a particularly good guide, as 80 watts from one light, 40 watts from each of 2, or one watt from each of 80 are going to give you entirely different lighting uniformity levels within a tank. Not to mention that a tank can be tall and narrow or short and wide.

Having PPF data, if you know the beam angle, you can estimate the PPFD at distance and figure out how to illuminate the tank properly, based upon the plants's needs.

100% agree with what ray said. look at the HLG website:

HLG 65 V2 LED Veg Grow Light - Horticulture Lighting Group

"With a total of 120 pcs Samsung LM301B LED's, this fixture produces 10,000 Lumens with just 65 Watts of power. Equivalent to 150W T5 or 200W CFL output or 150W metal halide."

as long as your orchids arent super high light requiring an hlg 65 can do 180 ppfd on the edges of a 2'x2' at an 18" height. your only issue is geometry- the fixture will spread minimal light as you get further away from its center. two of the seedling LEDs hung above the tank at roughly 18" length wise will give you a better more even spread and you can move the lights closer or further if you notice the plants aren't responding well.

link to linear seedling light:

HLG 40 LED Veg Grow Light - Horticulture Lighting Group

Just wanted to circle back around and share that I ultimately bought a HLG Saber and wired it up to a 90W power supply. I wanted the light placed inside my tank so this was a great waterproof option and it looks very sleek. The light quality is awesome and I’m waiting to see how my plants respond after they get used to it.

HLG SABER LED Grow Light (Power Supply Not Included)