# Super-Low PAR Lighting for All-Day Viewing



## Eugine Thomas (3 May 2015)

My tank lights are on for 7 hours a day: I want them to be on for 16 hours a day (so I can see the fish all day long). Is there a way of doing this without creating algae? I was thinking of a super-low-par LED strip. Would this work? Where would I buy a waterproof one? Can anyone think of an alternative solution? Thanks.


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## zozo (3 May 2015)

Consider  even if you go realy low light, most fast growing types of (stem) plants will react to it and you will force them to make longer internodes. Fast growing plants react to a minimum of light, i first noticed this with a simple blooming plant in the house. It didnt realy want to bloom, it was growing and blooming at the same time in a strange form shooting long internodes between the flowers. After a while i noticed the powercord whit such a multiconnector that was near the plant had a lit red glowing switch on it. And that was the culprit and lit the plant at night, did put a piece of tape over it and the plant stoped growing and started fully blooming as should.

Im using 21 watt smd 5050 led strip (3 x 7 watt 600 lum each) at the time above my tank. And that's not so much, brighter than a 30 watt TL but still. I also use a LED controller and my lights are never fully off. During the night i use about 4% RGB capicity. 1 % red, 2% green and 1% Blue, makes very dim white colored light with a slightly green touch to make the plants look more natural at night. Looks pretty neet. But i see my Elodea and myriophyllum brasiliensis do this. Making longer internodes which get shorter the more they reach the top of aquarium. So if you have stem plants and want to keep them bushy you might have a problem there.

What you could try to do is take some small led strips, with only 3 leds each in Warm White color. Depending on the lenght of your aquarium you can connect in series, say 3 leds p/12 inch and connect a dimable controller to it and play a litlle with it till you get the disered effect. 

Oh and yes you should buy IP65 or IP68 waterproof.. Not that 12 volts are that dangerous.. But it willl prevent oxidation in the connectors.


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## Rahms (3 May 2015)

zozo said:


> But i see my Elodea and myriophyllum brasiliensis do this. Making longer internodes which get shorter the more they reach the top of aquarium. So if you have stem plants and want to keep them bushy you might have a problem there.



This is what stems do in lowish light anyways, without night time illumination. Lower light means less dense growth, and light intensity increases towards the surface.


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## zozo (3 May 2015)

Rahms said:


> This is what stems do in lowish light anyways, without night time illumination. Lower light means less dense growth, and light intensity increases towards the surface.



Yup and i see them realy shoot towards the light, i have seen the myriophyllum brasiliensis growing 2 inches in 3 days, making longer internodes. 

Thursday last week.




Today




Realy rocketing.


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## tam (3 May 2015)

I've a grobeam 600 on 100% for 12 hours a day over a 70l tank, no algae but nearly 100% coverage of floating plants.

Most of my plants are anubias/javafern/crypt/buce but I think it might be stunting my Rotala Rotundifolia which doesn't seem to be growing much at all - I don't think its a fert thing as the floating plants are going crazy.


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## dw1305 (3 May 2015)

Hi all, 





Eugine Thomas said:


> I was thinking of a super-low-Par LED strip. Would this work? Where would I buy a waterproof one? Can anyone think of an alternative solution? Thanks.


You need sufficient light intensity to reach <"light compensation point">, if you don't then it doesn't matter how long you run the lights for, the plants won't be able to grow.





tam said:


> I've a grobeam 600 on 100% for 12 hours a day over a 70l tank, no algae but nearly 100% coverage of floating plants.


Same for me, I have my tanks on a 12 hour day, all with a covering of floaters.

If I was going to try a long day, low light intensity, planted tank. I would plant it entirely with plants that are very dark green (contain lots of chlorophyll) and grow really slowly. _Bolbitis heudelotti, Anubias _and some mosses might be a good place to start.

cheers Darrel


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## zozo (3 May 2015)

Darrel  i'm only telling my own experiences, i don't run a lab and i am only a very anthousiast gardener. Im dutch  which i cant help and what goes around comes around i hear and see... No body cares and if you are smart nobody sees . I dont want to be mysterious and call the baby by its name. I once got curious with all the stories and once did put some nono plants in my greenhous, Goerge Washington went president with it so why not. These plants bloom best at point 12 hours light, very compact and dense, actualy kind a pretty. Unless you put the tiniest light next to them at night and they start to grow again.

I challange you.. Test it, they realy do. There is plant activity also at night, by moonlight... As experienced hobby farmer with only a technicians background and life long interest in nature i sincerely doubt the sientific statement that they don't. I guess they didn't test all plants and just a variatie of logical choises and made a wrong bet.


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## zozo (4 May 2015)

Same aquarium with my bath tub babies, while ago, same lights, less plants other light schedule.. Denser Elodea then today.. But Low Par.. Only one RGB ledstrip 50 cm 30 leds over a 60 cm x30 x 30 aquarium. Night vision less than 10% total strip capacity.. (Beer) Can give you an effect like this.. And this is real time video, no fidlling around with any software.


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## dw1305 (5 May 2015)

Hi all,





zozo said:


> These plants bloom best at point 12 hours light, very compact and dense, actualy kind a pretty. Unless you put the tiniest light next to them at night and they start to grow again.


 That is slightly different, light levels below the light compensation point can have all sorts of effects on cell extension and initiating flowering etc. 

Have a look at <"phytochrome"> & <"light">.

cheers Darrel


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## zozo (5 May 2015)

Thanks  nice reads again. In what i've experienced and observed by chance i just have a hard time to believe that the compensation point is the same for each plant on this planet. I've observed some plants initiat growth with very low light input. That low that it is hard to believe it would have any effect, but it did. There are so many differnt plants with their own characteristics in growth and behaviour in different light conditions.

F.e i also got a small terarium with only a few plants.. I got a Biophytum Sensitivum in there together with a Bulbophyllum Tawainese. And i can realy observe a very different light sensetivity in both species. I having a hard time keeping them together. What's to much for the Orchid to keep her healthy is not enough for the Biophytum.

Also the statement that aquatic stemplants always will make long internodes in low light conditions is not generaly always the same as i observe. I got a pond outside with some same plants i have in the thank inside. Inside i have low light but still very much higher than the pond which is only lit by daylight and warmed by the sun. In the tank i use Co2 and firt and a heater. In the pont i use only some little firt. In the pont the stem plants grow slow and keep dense but still i clearly observe more assimilation and lots of oxygen bublles. In the tank they shoot like hell and make long internodes and less bublles. A while back the tank still was low tech, same lights, no heater, no co2, no firts only a few pooping fish.  (as in the dark video above) Had the same stem plant in there. They grew well and dense.

3 different setups and 3 totaly different grow behaivors with the same plants. All to do with a combination of light, temperature and food differnces.


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## dw1305 (5 May 2015)

Hi all,





zozo said:


> i just have a hard time to believe that the compensation point is the same for each plant on this planet. I've observed some plants initiat growth with very low light input.


 Yes, some plants will have a very low light compensation point. It is because we won't have experimentally defined PAR values that you have to guess which plants need the least light, and why I wrote this earlier in the thread. 





dw1305 said:


> If I was going to try a long day, low light intensity, planted tank. I would plant it entirely with plants that are very dark green (contain lots of chlorophyll) and grow really slowly. _Bolbitis heudelotti, Anubias_ and some mosses might be a good place to start.





zozo said:


> Inside i have low light but still very much higher than the pond which is only lit by daylight and warmed by the sun.


That is actually to do with the way that we perceive light intensity. Daylight is much, much brighter than any aquarium light. 





zozo said:


> Biophytum sensitivum


 I like this one, I was going to comment on it in the <"Show me your Orchid"> thread.

cheers Darrel


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## Marcel G (5 May 2015)

zozo said:


> i just have a hard time to believe that the compensation point is the same for each plant on this planet.



Here are some data from scientific papers that I gathered (all values are in µmol PAR):
LS = Light saturation
Km = Half-saturation constant
LCP = Light compensation point

Cabomba caroliniana (grown at 30°C), LS = 700, Km = 160, LCP = 55 µmol PAR.
Ceratophyllum demersum (30°C), LS = 700, Km = 145, LCP = 35 µmol PAR.
Ceratophyllum demersum (7°C), LCP = 7 µmol PAR.
Egeria densa (24°C), LS = >1050, Km = 15-35, LCP = 7-16 µmol PAR.
Egeria najas (25°C), Km = 35, LCP = 18 µmol PAR.
Egeria najas (25°C), LS = ~60, Km = 18, LCP = 6 µmol PAR (different paper).
Elodea canadensis (8°C), LS = ~105, Km = 25-60, LCP = 3-4 µmol PAR.
Elodea canadensis (7°C), LCP = 5-10 µmol PAR (different paper).
Hydrilla verticillata (30°C), LS = 600, Km = 80, LCP = 15 µmol PAR.
Hydrilla verticillata (24°C), LS = 1050
Myriophyllum brasiliense (30°C), LS = 250-300, LCP = 52-45 µmol PAR.
Myriophyllum spicatum (30°C), LS = 600, Km = 120, LCP = 35 µmol PAR.
Myriophyllum spicatum (25°C), LS = >2000, Km = 165-365 (different paper).
Vallisneria americana (25°C), LS = 140, Km = 60-200.

Generally speaking, mosses have usually lower LCP (5-20 µmol PAR), whereas stem plants have usually higher LCP (20-50 µmol PAR).


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## zozo (5 May 2015)

dw1305 said:


> Hi all, Yes, some plants will have a very low light compensation point. It is because we won't have experimentally defined PAR values that you have to guess which plants need the least light, and why I wrote this earlier in the thread. That is actually to do with the way that we perceive light intensity. Daylight is much, much brighter than any aquarium light.  I like this one, I was going to comment on it in the <"Show me your Orchid"> thread.
> 
> cheers Darrel



Yes you did.. Blush.. Excuse me, it's my English got a litlle rusty over time and sometimes i have to read things 3 times over (or even better, think twice and hush) to get the correct interpretation.

Biophytum sensitivum  indeed a very wonderfull plant.. Nice medical potential too.. Funny is to see how it reacts to light.. The terrarium is lit, but also stands under such a daylight thing in the roof with milky glass (forgot how you call that thing) But there is something in the daylight what the lamp above it doesn't have. When evening falls the plant goes to sleep and hangs its leaves down even when the lamp is still on. And in the morning when the lamp above already is on, it doesn''t react and stays dorment. The leaves spread only when the tiniest bit of first morning daylight comes in.


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## zozo (5 May 2015)

ardjuna said:


> Here are some data from scientific papers that I gathered (all values are in µmol PAR):
> .



That's great, would like to have that, where do you guys find papers like this?.. And a PAR meter too  would be fun to have. But not for $350.

Egeria (elodea) densa (24°C), LS = >1050, Km = 15-35, LCP = 7-16 µmol PAR.
Myriophyllum brasiliense (30°C), LS = 250-300, LCP = 52-45 µmol PAR.

These 2 i got as well at 24-26ºC, they almost grow in the same rate, The Hippuris also..


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