Marine Light for Tropical Plant Tank? + HEAT Concerns


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Dec 6, 2021
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If too long to read, please just disregard. My apologies :/ and :thanks:

I am providing a backstory because I posted saying I got the right light for:

My Needs → [Dedicated Plant Growth and Tropical Tank Use only] Instead I ended up with a Marine Light.

We made a mistake guys and I feel like such a goose after making a previous post thinking we has solved our lighting requirements. The light we bought is not what we thought it was.

We purchased the light from the FB Market Place.

Unfortunately we failed to notice the specifications provided was of a power supply and not the light. Due to short attention span, blurry image, bad framing, orientation and no actual user description combined with our excitement to complete the tank we made an ill informed decision.

The image in the advert:
I think it was the poor quality and orientation that lead our eyes straight from the Fluval branding to the model number without seeing the description 'power supply' Even then we dropped the D from the model number when searching online. As explained further below you will see how this lead us to purchasing this thinking it was for a tropical tanks that could grow plants ... and grow them well. Now we are not so sure.

Thier Image.jpg

The below image is one I took with my phone. Had I seen it listed like this I would of politely asked if they could also include the specifications labeled for the light. I am pretty sure they were just in a rush as moving house. This does highlight though why its important to take clear images that are framed well. I defiantly would of seen the D on the end and that it was a power supply and not a light compared to the above. That said, we were in just as much of a rush.
Specs on Power Supply.png

So it was the we entered ‘Fluval: A3992’ into the Google Search Engine. Who would have known Fluval had a tropical plant light that meets our needs with the same model number as another lights power supply; but missing D on the end.

The result we got was the ‘Fluval A3992 Aqua Fresh & Plant 2.0 LED, 48-60’ I immediately thought BINGO ... as I wanted a light that spells out PLANT. Had we include the ‘D’ when inputting model number, we would have seen power supplies come up instead. That said, I do suffer terribly with dyslexia. Also having take more time to investigate the adds image I probably would of read power supply.

Suffice to say after getting the light home we discovered that the light itself read as →[Model:14517 V1.03]
No big deal. That’s how we ended up with a Marine Light for a Tropical Tank ... which is intended for small fish and a LOT of plants.

The Fluval phone app read the device as:
Identified Device Via Fluval App.png

Searching further online at the Fluval Website using the model number as labeled on the light : Model:14517 V1.03
We narrowed it down to this: Marine Spectrum Bluetooth LED, 59 W, up to 145 cm (57″)

Fish Tank Light Specs.png


Turns out the light is comparatively expensive compared to other models and seems to be in full working condition and very bright! Between $400 AUD and upwards depending on retail outlet We bought it for $40AUD:

Here is another image I took with my phone and used photoshop overlaying the device info from the Fluval app image and model details from light's specs label:
LEDS in the Daylight full power position:

The LEDS.png

Image bellow to indicate light spread in bare tank on full daylight setting during the day:
Light demo One.png

Image bellow to indicate light spread in bare tank on full daylight setting during the early evening:
Not the best angle in the evening for this tank. I am not a fan of this pic as it shows too well the previous owners mistakes when it come to handling the glass. During the day the scratches hardly stand out and even during the evening its not as visually detailed as in this shot. Its more the angle that shows those scratches off. Nevertheless I include this photo as I believe it shows the light spread well enough for this tank. No doubt being on the higher end of power consumption it is a bright light. Most of everything in this tank is secondhand. I do beleive I will get it looking nice regardless of the scratches and blemishes. It was a leaky salt water tank that was repaired and then given up. The tank still had silicon all over the sides despite previous attempts to clean it up. I managed to get most of it off without adding to the damage. It will suffice as a reintroduction into the hobby and perhaps make good use in the future as a holder tank.

For now it shows well the light spread in the evening. Much of the gavel is over exposed - but - evenly so.
Light spread two.png

Inlet, heater placement and all that is not final ... I will be making lots of mistakes but also decisions based on other things that cannot be seen here. If you want to help me, I'll be making plenty of posts yet. For now this is all about the lights ability to grow plants WELL and the heat it is dissipating. The wood came with the tank. I have had better in the past. I might dig into it a bit here and there if not find a piece of my own.

I’m sure we can easily get more than what we paid for it. That said, I would not mind keeping it if in fact this light is able to provide the required light spectrum for thriving plants? That is the most important question to us above all. Nowhere in the manual or specifications does it even mention once the word plant? Thus we are skeptical regarding the lights ‘Thriving Plant Growth’ ability? It certainly has the reach & PAR from what we can tell? That side of things I am very impressed with.

Does this marine Light have the required spectrum for thriving plants in a tropical tank?

The blue light during the night whilst is a good idea with the dimming I find takes a bit of getting used to. To my eyes that seems rather unnatural; especially for a tropical tank. Would be nice if you could change those dimming settings to another color. I digress though:

Can anyone attest to the Plant Growth ability of this light when used for a tropical Tank meant for LOTS of plant where in fact Plants are as much the theme as the fish? At the end of the day that is all we need to know. I think not because not once in the description or manual does it mention the word plant?

However there is one more thing:

HEAT – Hot To Touch 40+ degrees Celsius on top of the light chassis. (is this normal for a light of this caliber to run so hot?)

Light Tmep.png
Light Temps.png

UPDATE Another reading showed 47.5 degrees Celsius
The updated 47 degrees was a result of when immediately taking temp after opening hood on tank after half of the day being on. Top of light chassis. Heater is set to 26 degrees and the light is still on. Seems to indicate the the HOT LED Marine Light is not affecting the water temps adversely at this stage. Just seems awfully hot though for LED light tech that is sold as COOL? My high end gaming graphic processer (Computer) idles cooler than that and it's not water cooled. Then again it does not have a hundred or so LEDS running at full power. I know LEDS on my bicycle can get hot after being on for a while and use a heat sink to keep if from overheating. Perhaps this is the some thing?

We are unable to determine if in fact the pictured power supply (2nd image in the post) is meant for this light and whether this may be the reason that this powerful marine light is dispersing so much heat through its chassis at 47 degrees Celsius. I’ll contact manufacturer shortly. Just wanted to run this by some of you guys first. The 24V 60Wat output of the power supply we have is 1 over the rated 59 watt as label on the light. Pretty sure that is OK. Because the light is second hand and the owners seemingly amiss with their advert it is hard for us to know if this is the original power supply intended for this marine light? Also the model number of the power supply emulates the model mummer of the following light; minus the D at the end:

the ‘Fluval A3992 Aqua Fresh & Plant 2.0 LED, 48-60’ So there could be some concern re this power supply?

I thought LED lights where cool? Once of the biggest selling points I have real alongside power consumption is that these lights run cool. So it was that I am confused as after touching the light when only being on for a short time, it was hot to touch.

The water temperature though does seem to be holding at 26 degrees which is within the tropical tank range general speaking. This light is also the largest and most powerful within its range as cited on the Fluval Website. So I am thinking that perhaps with that kind of PAR / light intensity that it may be normal for this light to be dispersing heat throughout the chassis at 47 degrees Celsius?

Under the glass seems cool enough and again the water seems unaffected and still around 26 degrees Celsius?
This pretty much covers the story of the light we now have as well as my concerns re a tropical tank intended for many plants but now stuck with what seems to be a very nice marine light that spans out tank quite well, just unsure if its running too hot and lacks the ability to grow thriving plants?

If you forgot what I am asking - just skim the bolded sections.

If you made it this far – you’re a legend!

Guess what … I got more questions. Lol ... I save that for later.
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THE SHORT VERSION - in the follow communication I sent to Fluval.

My wife and I just purchased the ' Marine Spectrum Bluetooth LED, 59 W, up to 145 cm (57″)' light second-hand. We did not realize it was a marine light. What we would like to know is:

A: Can this light be used in a Tropical Tank as well as provide the correct spectrum for plants to thrive? Nowhere in your specs or manual do you mention the word plant once.

B: We have used a Hand Held Point and Shoot Temperate Gauge to measure a surface temperature of 47 degrees Celsius across the top of the light Chassis. Yet the water temperature is holding at 26 degrees with the heat light on and set to 26 degrees. Should we be concerned about the light chassis being 47 degrees Celsius

C: Could you please confirm if the following 'power supply' with the model number:
Fluval: A3992D is the original power supply for the Marine Spectrum Bluetooth LED, 59 W, up to 145 cm (57″) ← It's model number is [Model:14517 V1.03]

The reason we would like to know if the power supply mentioned above is the correct power supply is not only because of the temps we are recording, but also because the model number of the power supply that was sold to use with the afore mentioned light is the same model number of another light called the [Fluval A3992 Aqua Fresh & Plant 2.0 LED, 48-60’] except without the D on the end.

We are new to the fish keeping world and would greatly appreciate any help you could provide in answering these questions.

Thank you for your time and consideration
XY & Z
very busy period so not expecting a reply any time soon.
Feel free to chime on in. ;)
The problem is that planted aquariums require warm light and you have cool light. What I would do is, add a pink or red warm light to what you have. Personally, I wouldn't get rid of this light but just add some warmth to it. There is a lot of fuss made about light spectrums for plants, we aren't that clever. Add some warmth to what you have and then buy a mixture of plants and see what does well. Somethings you will grow others you won't, so be it.
You can use marine lights on freshwater tanks. The main difference is in the blue and ultra violet colour spectrums on marine lights. They are usually much higher than freshwater plant tanks, and your light appears to have a 25000K (K is for Kelvin) rating. The average daylight globe has a 6500K rating. The higher the K rating, the more blue, purple and UV light in it.

This doesn't mean you can't use the light for freshwater, you just have too much blue, purple and UV for an average planted aquarium. If the light unit allows you to vary the different wavelengths of light, then just reduce these colours a bit.

Plants like an even mix of blue and red light with some green thrown in.
The blue, purple and UV light encourages corals to luminess.

In the morning when the sun comes up, there is more yellow and red light hitting the Earth. As the sun rises in the sky, more blue, purple and UV light hits the earth. By lunchtime, the blue, purple and UV light is at its maximum concentration. In the afternoon, these colours become less intense as the sun goes down and red and yellow light become the dominant colours.

I am not sure why companies tell fish keepers to have blue lights on at night because it doesn't replicate moonlight.

High output LED lights can produce a bit of heat. Try to raise the light unit above the tank so less heat gets into the tank. Have any hoods open at the top so the heat can rise up away from the tank and light unit. Most light units last longer if they run cooler, so having better air flow around them helps.

If you bought the light unit from a shop, take it back and swap it for something with a 6500K rating but the same lumens (2550 lm) as what you currently have. Otherwise just use it as is and try to reduce the blue, purple and UV settings.
Thanks for the that information Colin. The app does appear to allow for adjusting the spectrum.
Until I hear it spelt out that the UV in these lights have the properties to make plants grow healthy I am unable to move on.

I appreciate the info on the color spectrum, but still do not feel my question is unanswered regarding the light having all it needs to grow plants. Like are you saying yes or kind of? I know that UVB has nothing to do with color and am thinking just as it is with humans, so to it can be with plants. Hopefully the manufacturer can give me a yes or no answer.

I already mentioned that I bought it second hand. No drama though. I am just looking for an answer before I see it due to being an inappropriate light for growing plants. Once I get my newbie yes or no answer, I will know where to go for there.

I love how bright it is and the heat issue I am only worried if the light is faulty or not. The temperature of the water does not seem problematic due to the very high temp of the light itself and like you say there are measures I can take if that becomes an issue. I may raise the light some but will not take the hood off because the water is not negatively impacted at this stage. Again the high temp is more a concern whether the light can sustain it or whether it is normal. That I feel you have answered. TY. You probably answer the part re plants but I am the kind of guy that lacks the knowledge and thus without a yes or no, leaves me in the unanswered dept.

I'm sure someone will come along and spell it out clear enough. lol

I'll implement some of those options you mentioned for sure. If I can't get a tannin like color happening once the tank is full of plants and enough wood with a few fish I'll definitely sell the light for it's intended purpose - a marine tank. From what I can tell, it seems people are turning their tanks into Xmas trees these days. That's great and all, but something I will just leave to the inside of my computer case.

I'll for the colors like you say - but just think there may be something more important than just color that this light does not have for plants.

Thanks again.
The problem is that planted aquariums require warm light and you have cool light. What I would do is, add a pink or red warm light to what you have. Personally, I wouldn't get rid of this light but just add some warmth to it. There is a lot of fuss made about light spectrums for plants, we aren't that clever. Add some warmth to what you have and then buy a mixture of plants and see what does well. Somethings you will grow others you won't, so be it.
Yea thanks - Colin was also explaining a little bit like so. But like I said to Colin, I wonder if there is something else in the light other than color that plants need? That is all. That said, I am going to do exactly as you guys suggest.

The part about so be it ... will not be for me. In my world and my tank, if this light is found to be lacking in plant growing properties - the light will be sold to someone else who cares less and then and only then, will it be - so be it. :hyper: Just kidding - see below:

Agrees it was a score for such a small price - but once I know what makes a good aquarium grow light other than just the colors - and or what is a better light for the money - I will pay the price and pass this one on whilst making a buck.

I don't know - I may be wrong and all I need do is change the color of lights. I've always thought the photosynthesis require something else other than just the angle and color of light? If that is all it is - then are you saying I won't get enough spectrum to grow a wide rage of plants ... but only some? If so - then I will look to change the light to one that has a better range.
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Thanks guys - I adjusted the setting on Manual and Auto as well. I even lowered the light intensity to get a more natural look. The color looks way better to my eye. I think the light will run cooler now that it is not turned up so high. Thanks to you guys I think I can work around it but when I have time I am going to research more on what makes a good aquarium plant light and invest some money into that. This light seems pretty up there with the tech and I'm sure I'll make a dollar when upgrading. It will do for now until I get a dedicated plant light. I see the app on the phone has a Fluval Plant light app. I'll look into that as well as other options.

Thanks again - I just need to make long winded posts in order to process. It's been fun. Thanks for the education in kelvin. :) I'll post comparison pics re the different colors I was able to achieve when I have time.
Without seeing a colour spectrum chart, it is impossible to say whether the light is suitable for plants. However, if you can change the wavelengths, then you should be able to set it up for plants. Just try to have equal parts of red, blue and green. Red and blue is the most important though and the green can be anywhere form half the red & blue spectrums, to the same amount.

Most plants don't use much if any UV light but it does have an influence on them. A lot of plants have flowers that appear as a different colour under UV light and this is for the insects that pollinate the flowers. Aquatic plants don't normally have flowers but again, they have evolved under sunlight, which contains different wavelengths of UV light.

Most freshwater aquarium lights do not have UV light and it is not necessary for plants to grow. UV light can be harmful to bottom dwelling fishes like catfish and loaches who do not normally get exposed to UV light. Other fishes like rainbowfish are fine with UV light and quite often develop better colours when exposed to some sunlight.

If you can remove or reduce the UV light, and increase red & blue light, it should be fine for the plants.
Thanks again Colin. I sense I am getting bogged down but just trying to make the most of this light is all. I can't thank you enough for hanging in there with me. Your continuing like so with me is helping me to see the bigger picture. I manage to throw the little video together just showing how I set it up to transition through the day and night cycle. I admit I cut out the blues entirely as the moon light mode has put me off blue altogether.

My I ask that when you say equal amounts of blue - do you mean to add both Blue and Cyan with the Purple and Pink all being equal levels? I show you a snap shot of how I set the video example up but now go make another video doing equal amounts if I have understood you:

1st video with next to no blue during day cycle:


2nd video with equal amounts of all colors

I think I will call it a wrap for now. Like I say, I really dislike the DARK BLUE. I don't suppose the Cyan is blue enough light or should I being using both blues with regard to plants?

Thanks for being patient with me. I tend to tire easily. lose track and get frustrated with my thinking. I have tried to be thorough but also mindful as I can be. I admit I am a guy of extremes. I probably wont rest until I can get a light that is way less BLUE yet have the right colors for gowning healthy plants. I do like this lights ability with the phone app but look forward to upgrading the light for a less bluey feel. If I am to use all equal amounts that's OK I can live with that for now. February I come into some money. I may consider even changing that glass out for one that has no scratches. We at least have a good start. Again - really appreciate your patience . TY. People in Reddit can be rather cruel about my spongy nature. Of course some genres tend to have more tolerant people than others. I suppose I won't be here that long. Maybe once I get some fish it will help. :)
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I'm assuming the purple is the UV light and that should be on during the middle of the day.

It looks like you start the light cycle around 5am and go through to 7pm, with most light being on between 6am & 6pm. This is fine.

I would start with pink first (5am-7pm), then 30-60 minutes later, add white, then 30-60 minutes after that add cyan, then blue, then purple. That would replicate the sun as close as you can with red and yellow light being the first light we see in the morning and last we see in the evening. Then the blue and purple kick in a few hours later and come to their peak around lunchtime. UV light and blue tends to be strongest between 9am & 4pm. The white light can come in any time after the red, and go off before the red/ pink.
Thanks Colin, I will certainly give that a try. Sounds like a good choice of colors to me. I have far too much blue in the mornings and evenings as the light dies down. I'm just about to swap computers as I work on this one but will be sure to get back with a video based on the last colors you mentioned. Yes they are the times I have set. Look forward to giving it a try once I have time. Thanks again and take care. ;)
Hey - here is an update. I have tried keeping your suggestions in mind whilst reducing the deep blue light that I do not like. This is what I have come up with. Please note that I found it hard to get the minutes exact as the 10 time stamps where very close and my fingers fumble a bit even with a stylus. I got confused about the turn on and shut of times and have made notes to the changes I would like to make in yellow text. I'll upload the screen shots and hopefully you can make out how I currently have things working. I know you said a graph would be helpful. This is the best I could do with the screen shots whilst the overlays may look chaotic ... they help me see the bigger picture, remember settings and fine tune things.

My aim was to get more a river look but will have to suffice with just minimizing the deep blue. I'll keep experimenting as I am still waiting on air stone pump and another internal filter as the external one that came with it is imo not cycling 5 times the tank in one hour. Given that once the tank is populated the external filter will only slow even more. I will make another post about that later on perhaps doing a test to see exactly how limited the pump I have is. Like I say - I have to make another post but is not a major issue right now.

Here are those images:


Sequences: One side mirrors the other - see colored numbers on bottom of bellow image. Note* There are 4 light changing Cycles - See Last Image
The changing light cycles are represented by the white arrows in bellow imaged that correspond with the black lines. The cycles change 4 times building up where the 4th cycle is the Peak and the first being first and last light. Thinking out loud to learn how it all works. Correct me as you will. Turning off and on times I go confused but think I now understand.

The 4 Light Cycles:

Light Cycle.png


I much prefer the softer/darker light around 6am to 7am and wish there was even more of a tannin color. I am thinking I might replace the wood for something that leaches more tannin and add more of it. I'm also hoping that lots of plants will assist in ridding the cold blue look. This was the best I could do for now. I will be looking in the future to get the correct light for this tropical tank. But for now - The changing of light intensity is something I like and really hope I can get one that does the same thing but more in a tropical plant light that resembles more of a brownish look. I might try some pebbles as well. I'm pretty sure what goes in the tank can have an effect on the color with regards to tint. I really loved the previous one I had set up so many years ago. Was like under a river with a very clean brackish look that was still well lit. It is in that knowing that I am finding it hard to live with this light for my intended purposes.

At any rate - I hope I am on the right track to using this light correctly in terms of adjusting colors and intensities. To be sure, we will make do contently in the meantime. Really appreciate the advice. It helps tremendously. 👍

EDIT* PS - I hope you can see - my corrections are in line with your suggestions re time and I also tried to stick with the colors you said as well ... but just had to dial back that deep dark blue. I wish I could even dial back that dark blue even more but worried about plant health if I do?
The lighting looks good now. :)

If you don't want it as glary, add some dark substrate to cover the white and it won't glow.

Tannins and floating plants will also reduce the glare.
Your post is too complex for this newbie. I am using a Fleval Aquasky 2 on my freshwater tank. My intuition says you can probably adjust the settings
to suit your needs. If not resell or keep for the future.

Here’s my settings.
Your post is too complex for this newbie. I am using a Fluval Aquasky 2 on my freshwater tank. My intuition says you can probably adjust the settings
Jenny, you need to increase your blue & red light so it's the same as the green or higher than the green. Plants need equal parts red and blue light and some green thrown in. You have no blue, only a bit of red, and lots of green.

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