Hydroponic Lights

[Luca]

I have recently learned that using hydroponic lighting setups are a viable option for lighting (planted) fish tanks :)

I'm sure there's been tonnes of discussion on this already (links to threads welcome), but if not, what kind of wattage should I be looking at getting for my 75 gallon tank? My local has 250W, 400W, 600W, & 1000W. I was thinking 400W (5.33 W/gallon)?

What about metal halide versus high pressure sodium? Someone on another forum said HPS lights aren't good for plants, i can't see how that can be true?

Thanks for any info

PS: I intend to suspend the MH or HPS light from the ceiling. This will reduce its effect so maybe 600W is better?

[Carolina discus]

Luca,
Don't know if you are interested but I have a 1000w HPS system for sale. Let me know and we could work something out...
Thanks,
Eric

[ChloroPhil]

I wouldn't use any more than two 150 watt bulbs over a 75. Hydroponic fixtures are meant for plants growing emersed and will cause all sorts of havoc underwater.

Best,
Phil

[Rob]

Try
www.thekrib.com
go to the plant section or hardware (lightning)

Using grow lights are what reef keepers have done for years.

Using these high output lights is similar to having direct sunlight on the tank, ALGAE lots of it, unless you have plants healthy enough to use the nutrients in the tank faster than the algae.

The amount of light used is based on depth of water, surface area and the amount your plants need.

None of my discus like that much light.

[Luca]

Hey Eric did you have that 1000W setup on a freshwater tank? Everything i'm reading on google is bla-ing on about marine!

My tank is heavily planted but I know it will do a lot better with increased wattage. I guess if it causes algae problems I could just raise it higher above the tank to lessen its intensity. Apparently 2X further away 4X less the intensity.

Is there better alternatives for getting me up to at least 4W/gallon (300W)?

[Carolina discus]

I have never used the HPS over tanks....they were used for another project in my younger days ::).....
A light of this size would need to be used for a 10x10 fish room. It throws off way too much light for a single tank. It is truly like walking into a room with the sun in it.
Like I said, it has been in storage and I thought maybe someone would be interested.
Phil would be the expert on plants and lighting...I would go with his recommendation.
HTH
eric

[Moon]

For a planted tank you need a light source that is close to the daylight spectrum. Metal halide lamps have this spectrum. It has a wide band continous spectrum including most colours of the spectrum.
HPS is a sodium lamp with selected spectrum in the yellow and red area with very little green and blue. Experiments carried out in Reading University in UK on the use of HPS as agrow light on tomato plants showed that the plants grew fast because of the high light intensity, but the growth resulted in thin spindly plant and not lush full growth.
HPS lamps are not recommended for plant growth. It is a very efficient light source for applications where colour rendering is not important. Metal halide of full spectrum flourescent is the way to go.
I experimented with a 150 watt MH lamp on a 30 gallon planted tank. Plants grew well and fast and so did the algae. Eventually hair algae took over the entire tank and my plants suffered. Changed to two 20 watt full spectrum fluorescents and the plants are doing great and so are the fish. :) :)

[Luca]

I just can't understand how 1.33W/gallon is enough light for your plants to grow. My plants grow all right with 2.13W/gallon but they don't grow lush and green as you would find at the LFS. My carpet plants also never go anywhere, as if they are just waiting for more light. I want there to be ample light and ample growth. I am now looking into halogen lighting. My local hardware store has 150W ones for $10! (bulb included). Two of these would get me my desired 4W/gallon but I have also heard they don't have an ideal spectrum for plants but the person who said that is also using one combined with two fluroescents with success. Hmm just did some research and i think i'll flag that idea as they have low spectrum, high heat, and 3-4X less efficient than MH apparently.

My tank isn't that bad, and i'm thinking "if it ain't broke don't fix it" but at the same time I want ideal lighting, pearling/photosynthesis, and lush looking plants. My red plant looks reddy-brown and doesn't grow much at all, far from the lush red it should be. CO2 appears to make very little difference. I think red plants require a lot of light??

Thanks for the info about the brightness Eric, I didn't realise it would be "that" bright. Seeings as it's in my room that wouldn't be ideal either.

One of the bulbs (Son T Agro) that only comes with the HPS kitset states: "the SonT Agro 400 has duel elements in it which put out both the blue and red light spectrum. Although the HPS is a flowering lamp you can easily use it to threw out your whole grow cycle."

Despite this, MH is sounding by and large the way to go. Although one reservation is I hear it has a high blue output which may make my tank look marine like perhaps and I've heard blue light causes a lot of algae growth (seems you've experienced this moon). However, if it does indeed have the full range spectrum then it must be the best option.

Anyone know if the ballasts are noisy?

I'm thinking I should go for the 250W MH now. This equates to 3.33W/gallon.

Thanks

[jared]

Here is some food for thought. Wattage ratings are not equivalent between the different types of bulbs. 100w of incadesent light is not the same as 100 watts of flourescent light, nor are either of these the same as 100 watts of MH or halogen. I am not an expert on this but I know it to be true. As for the HPS vs MH, a lot of commercial/academic setups use MH pendants in greenhouses to promote growth and HPS pendants to induce/promote flowering. While completing my bachelors degree I did three years of student research in crop science. From fall up until spring we would run only MH to promote overall growth. Every spring we would fire up the HPS in conjunction with MH to remind the plants it was time to set seed. Don't quote me on this but there is something about the increased red spectrum light in HPS that is responsible for this. I think it either triggers a seasonal shift int he plants or possible the developing flowers absorb for red. This is just speculation though.

[jared]

Luca,
Most carpet plants and red plants are high maintinence. They need more light, more nutrients and more time to establish. No matter what you do, they will grow slower than stem plants and vals.JMO. If you are not getting the red you want out of them add an iron supplement. Also, think about thinning your supply of fast growing plants. This will provide less competition for your slower growing plants. As for CO2, the fact that it does not make a lot of difference in your current setup does not neccessarily mean it would not under different conditions. It could mean that right now there is some other factor in shorter supply than CO2. This may be related to your difficulty attaining red plant growth/coloration. Could be Iron, could be light, could be nutrients. As a general rule faster growing plants will suck up nutrients depriving slower growing plants if there is a low bioload in the tank (hence the suggestion to thin out the faster growing plants). Also JMO. If you decide to try something new, keep a bottle of plant safe algae killer on hand. Algae loves a lack of balance in a tank.
Jared
Jared

[Luca]

Thanks Jared good advice IMO :)
That makes sense, I do have a have a lot of stem plants (ambulia) and some val (twisted and jungle). Maybe they will do better if I move them away from those plants in to some clearer areas I have available. This way they will get more light and more nutrients. I add PMDD (poor man's dosing drops - was a student till recently ;)). This contains iron in the trace element. My nitrate is virtually indetectable (which i first thought meant it must be "re"cycling but I realised was actually plant absorption when ammonia and nitrite tests came back 0). I have just added some more nitrate to my PMDD so this may also make a difference.

My research also showed that wattage varies (hence i'm no longer pursuing halogen because 4X less effective) and that the HPS is used for flowering whereas MH is best for vegetative growth (the kind we're interested in). Thanks for confirming.

[ChloroPhil]

Luca,

The wpg rule of thumb is very dependant on the type of bulb you're using. It'll take more light from Normal Output fluorescent bulbs to achieve the same effect as PC fluorescents simply due to strength of output. MH have the most intense output of any bulb on the market at the moment so would require even less wattage (power use) to achieve the same amount of Photosynthetically Active Radiation (PAR). Be very careful with MH over a planted tank, they're so intense that it's easy to overdo the lighting and cause all sorts of problems with alage.

As for your Nitrate levels, they need to be in the 5-10ppm range. It doesn't matter how much light you've got if you're plants aren't eating right. :)


Jared,

Your MH/HPS info is very interesting and makes a lot of sense. In general Sodium vapors are high in the yellow/red spectra while MH can be of many different color rating spectra.

Without doing any experiments I would guess that it has to do with corellations between earth-sun angle and spectral absorption in the atmosphere. Since red light has less energy than blue light the obliquity of the incoming radiation vs. earth's surface allows for greater diffusion/reflection of the red spectra increasing the percentage of blue light reaching the plants. As the earth-sun angle gets closer to 90 (direct radiation) the amount of red light increases accordingly. It's no surprise that plants have adapted to recognize that more red light equals better growing conditions and so go to flower and seed.

Don't quote me, but that's what I think is the likely explanation.

Best,
Phil

[Moon]

Jared
You are right. Various lamps have different efficiency ratings. Lamp efficiency is measured in lumens per watt. Here are some figures:
Incandescent 20 Lms/watt
Halogen 25
Flourescent (plant grow type) 40-50
Compact Flourescent 70
Metal Halide 80
HPS 110
You can see that the more efficient the lamp the less watts per gallon is needed. A metal halide lamp is four times as efficient as a halogen lamp.

Some of the new grow HPS lamps have a wider spectral distribution and may be suitable for plant growth. It will be interesting to have a combination of HPS and MH over a tank and how how plant growth is effected. I will give it a try.

[Luca]

Thanks for all the info and that chart is really useful too Moon.

If we derive that MH has twice the efficiency of normal grow fluorescents, that means a 250W MH bulb i'm looking at actually will put out 500W. In my case this translates to 6.67W/gallon!! Moon, you would've had 10W/gallon with your 150W MH over 30G!! (i.e 300W/30G). No wonder hair algae took over. I've also had problems with hair algae which I think I'm just getting a hold of now. Actually it hasn't been as bad as it was for a long time, I must be getting things into some kind of balance woohoo. Never thought it would happen :) Now I just have to work out how to get rid of the protein and green slime looking stuff from the surface.

[jared]

Cool stuff guys. I use pcf most of my planted tanks with a little bit of vho action and standard flourescent on small tanks. I would go for MH but the cost is a bit to high for me. And the heat is killer on those things. Give me an icecap 660 on a big planted tank and I am fine. 8)
Jared

[Luca]

what are cf or pcf lights? I'm guessing compact fluorescents but I don't think i can get them here. I suppose I could ship but I doubt i can sell the $350NZ 4X40W aqua one bulbs for what i bought them for! I guess i'll wait on the MH till i have a place of my own and can have a massive 6X2.5X2.5 tank. Does MH spread out well or is it quite directional/spotlighty like halogen?

Che Cher

[Moon]

My MH was only about 6inches from the water level and heat was a real problem. I have since changed to regular fluorescents with grow light lamps. I've got Crypt Tonkenensis growing wild in my tank with some Anubias and Java ferns, It is quite possible that these plants are low light plants.
I don't have plants in my discus tanks. They are bare bottom.
I would recommend metal halides for high light output and not halogens. Halogens produce a lot of heat being an incandescent lamp.

[ChloroPhil]

Luca

MH are both directional and well spread out if that makes any sense. They will put out a lot of light into any area their output can get to, but it's going to be strongest under the bulb, just like any other light. However, being a single compact bulb the range of effective light is pretty narrow compared to a long bulb such as a Normal Output fluorescent or VHO fluorescent.

What's the footprint/area of your aquarium? A single MH bulb may be just what you need. They're great for tanks up to 30" long/wide.

Check out this link to my friend Luis Navarro's website. He's got a 30g cube (24x24" I think) with a MH pendant over it.

http://www.mynatureaquariums.com/soon/index.html

I'm pretty sure it's possible for you guys in NZ to get Dual Ended MH bulbs. If so, a couple DE (aka HQI) 70w halide lights would be AWESOME over any tank. They're small enough to fit over a 2.5g aquarium (I've seen some reefs with them) and are generally affordable enough to put multiples over any aquarium.

Best,
Phil

[Luca]

I'd love to have 2 or 3 of those vertical MH lights pictured in that one shot there. What are dual ended MH bulbs?

My tank is 48"X20"X20" (120cmX50cmX50cm).

The bulbs at my local hydroponics shop are all horizontal, which I imagine would spread the light well, but as the tank is my room may not be ideal for the human occupants.

Those are truly amazing aquariums your friend has there. That red plant on the 58G is stunning. I think I will have to ask him what substrate he uses etc. Under "coming soon" (the link provided) i really like the cardinal tank. So simply but striking. Lots of peat may make that look even better I think.