A Q ABOUT LEDs AND PLANTS

[goose]

O.k i got a 100gallon aquarium and i want to put more live plants in it... Would LEDs help the plants grow??? I know that most plants need the proper light to grow but got no idea if the LEDs do. Another Q is does anyone sell LEDs that can be submerged under water??? I want to install some light on top and a few underwater as well.. Any one has any idea on the best way to go about it????

Alex

 

[odessit]

LEDs themselves could be submerged in fresh water, just keep the driving circuit out or waterproof it. I would insulate the wires/contact points on LEDs too, just to prevent corrosion and to cut down on current leakage.

 

[StarHalo]

Put a Sylvania Dot-It in a Ziploc bag, presto, amazing waterproof lighting for six bucks. Dot-It's also have an adhesive back, so you can have the same lighting above.

I'd be concerned about how well plants would do with LEDs, there might be some spectral issues there that plants might have a problem with. You should give it a try and update us on your results.

 

[bbgobie]

There's a 2 page thread about this further down the page...

 

[goose]

Where can i get the LEDs That would be sealed. I dont want any Current leaching in the water as that can effect the fish.. Main concorn is how to solder the wires to the LED and seal it after.. Thanks for the heads up on the other thread.. Going to read it now.. Im sure i would have more Q but i would post them as they come up.. Would a power inverter from 110ac to 12dc be a good idea???

Alex

 

[Oznog]

Right, read the "LED grow lights" thread earlier.

I don't think immersion is practical, not unless you're really really advanced. There's just no simple and reliable way to interface wires and a sealed container, not for a beginner. Even silicone doesn't stick really well to wiring and water may creep in. It's dicey that your wiring insulation would not leach water in eventually with constant immersion. Even if it didn't leach water in, it may leach chemicals OUT.

Corrosion on copper wiring is highly toxic to invertebrates. That would be a prob for salt water "live rock" tanks.

You could always get a long tube sealed at the bottom, weight the bottom, and insert your LED package down in it so the top where the wires exit is above water. But... all this is too much trouble IMHO. Just put the lighting outside the water!

 

[Oznog]

There's also a problem keeping immersed lights cool. If it's just a few 5mm T1-3/4 LEDs, you don't need a sink, but those won't help grow much of anything.

 

[goose]

Been reading alot the the past couple of days and it seems, That i might as well to the store and pick up a regular light.. The lights they sell are 25w and they are made for the plants and the fish..The set up would cost me $40. If i wanted to make it from LEDs. It would cost me 3 times as much and would take about the same power. If i just wanted to light up the fish then a few white LEDs would do the job. But i want to have live plants as well and thats a killer. But i did learn some intresting facts from all the reading. Thank you guys for the help and pointing me for some reading material which took me to alot more reading... Sometimes there is just way too much to read on the web lol...

Alex

 

[Oznog]

People have enjoyed putting bluish tint LEDs over the tank at a fairly dim power for a "moonlight mode". A fluorescent tube cannot be dimmed nor made bluish.

As per a prior thread, we believe (but have no clear objective proof) that blue and some specific "Deep Red" LEDs will grow plants are far lower power. It will be moderately expensive and unappealing to view the tank under this lighting. But the plants would love it. High intensity could be achieved (though at high cost) without heating up the tank which is a problem with too many lights. It is possible to saturate the photosynthetic capacity of the plant and additional light will produce no additional growth.

 

[AA6TZ]

O.k i got a 100gallon aquarium and i want to put more live plants in it... Would LEDs help the plants grow??? I know that most plants need the proper light to grow but got no idea if the LEDs do. Another Q is does anyone sell LEDs that can be submerged under water??? I want to install some light on top and a few underwater as well.. Any one has any idea on the best way to go about it????

Alex

Alex -- This is just rough guesswork on my part, but maybe you could determine which spectrum of light the particular plants you'll be using require for maximum growth / benefit, then choose the type of light that would work best while submerged. Oznog nailed it when he said that a few 5mm T1-3/4 LEDs could be successfully operated while submerged and without need of heatsink(s) -- but wouldn't help to grow much of anything.

I prefer using LEDs in virtually every lighting application . . . and, depending upon my mood at the time, may FORCE them to work in applications & conditions where they ordinarily would NOT! :thumbsup:

-Clive

 

[Oznog]

Well, innovation seldom makes money-sense. Not right away, anyways.

If your bottom line is cost, then LEDs are not the way to go. Fluorescent is cheaper. LEDs can be dimmed, the heatsink can vent the heat away from the water (not really a significant issue with fluorescent anyways). But mostly they can be something "cool". I mean the whole fish tank thing- who said it made financial sense in the first place? Cost hundreds over the years and never brought in a dime. All it ever did was look cool. LEDs could make it cooler... or tacky, depending on your presentation.

LEDs could- in theory- provide a lot of PAR (photoactive radiation, no units exist, I'd propose "grow-mens") with less power used and less heat created. We have the PAR charts but are still a bit unclear on exactly what wavelengths might be needed for specific plants and unfortunately this is a bit difficult to study with acceptable precision.

Actually, given that a significant portion of generated light is reflected off the water's surface as well as the light not being focused on the plant area, I believe there could be a significant gain in submersion or some sort of light guide- but, as these things go, not cheap or easy.

 

[blasterman]

O.k i got a 100gallon aquarium and i want to put more live plants in it

You'll want CO2 injection more than anything else. Pretty much any 5000k or above fluorescent will work fine. You'd need one heck of an array of LEDs to produce enough light to punch through a 100gal tank.

I've kept reef tanks...hard enough on a 400watt HID let alone LED.