What lighting should I get for my plants and fish?

[MyDogSpot]

Hi guys, I am planning on setting up a 150L (39.6 us gallons) long aquarium, I will be having platies as the fish and maybe some snails. The tank will be light to moderately planted and the plants will be Java Fern, Java Moss and Anubias species attached onto some bog/drift wood and aquarium safe rocks. The inner dimensions of the tank are 902mm (35.5") long, 454mm (17.8") high and 368.5mm (14.5") wide. So as the title says, what lights would yous recommend? Because I am really not sure on what to choose

. I have read about PAR, PUR and some other aspects of lighting, such as kelvin and lumens, but still quite stumped. I also read that watts/gal is not good enough to use any more, how true is this?

Thanks in advance people.

 

[Byron]

Watts per gallon is unreliable as there are so many different types of lighting. Watts is simply the measurement unit for the amount of energy a bulb or tube requires to emit the light. In the days when we all used T8 fluorescent tubes, or incandescent bulbs, this was something of a guide. But watts is not indication of intensity unless you are comparing absolutely identical bulbs in different wattages.

The plants mentioned are all low light requiring, so forget T5. That leaves T8 flutorescent and LED. I have had terrible experiences with the LED I have tried, so I will leave LED to those with success. You need to know what you are getting, and it is expensive.

The problem with T8 is it is becoming much harder to find. Do you have any light fixture now? I'll leave this for the present.

As to Kelvin, this is important. Kelvin is the colour temperature of light; the lower the K number, the "warmer" the light, having more red and yellow in the mix and less blue. The higher the K number, the "cooler" with more blue and much less red/green/yellow. Most LED is high in blue with insufficient red for plants (red drives photosynthesis, along with blue, but red is the more important of the two). Mid day sun is around 6000K, and Daylight bulbs/tubes with 6500K have been shown to be the best plant light. If you have two tubes, you can mix the types, with one 6500K and one 5000K or 5500K for a slightly warmer white. You want to avoid the high blue and actinic, these are fine over marine tanks where this is needed for corals but not freshwater plants.

PAR is similar to Kelvin in that it deals with the colour rendering. The higher the PAR up to 100 the more natural the colour rendition will be. I have found that 5000K to 6500K provides good colour rendition without worrying about PAR as well, but such tubes will usually be in the high PAR numbers.

I usually don't bother with lumens, but then I have always used T8 fluorescent or on smaller tanks the CFL bulbs, and I have worked out exactly what I need for my plants and fish, so I stay with it. Makes life simpler.

Byron.

 

[MyDogSpot]

Watts per gallon is unreliable as there are so many different types of lighting. Watts is simply the measurement unit for the amount of energy a bulb or tube requires to emit the light. In the days when we all used T8 fluorescent tubes, or incandescent bulbs, this was something of a guide. But watts is not indication of intensity unless you are comparing absolutely identical bulbs in different wattages.

The plants mentioned are all low light requiring, so forget T5. That leaves T8 flutorescent and LED. I have had terrible experiences with the LED I have tried, so I will leave LED to those with success. You need to know what you are getting, and it is expensive.

The problem with T8 is it is becoming much harder to find. Do you have any light fixture now? I'll leave this for the present.

As to Kelvin, this is important. Kelvin is the colour temperature of light; the lower the K number, the "warmer" the light, having more red and yellow in the mix and less blue. The higher the K number, the "cooler" with more blue and much less red/green/yellow. Most LED is high in blue with insufficient red for plants (red drives photosynthesis, along with blue, but red is the more important of the two). Mid day sun is around 6000K, and Daylight bulbs/tubes with 6500K have been shown to be the best plant light. If you have two tubes, you can mix the types, with one 6500K and one 5000K or 5500K for a slightly warmer white. You want to avoid the high blue and actinic, these are fine over marine tanks where this is needed for corals but not freshwater plants.

PAR is similar to Kelvin in that it deals with the colour rendering. The higher the PAR up to 100 the more natural the colour rendition will be. I have found that 5000K to 6500K provides good colour rendition without worrying about PAR as well, but such tubes will usually be in the high PAR numbers.

I usually don't bother with lumens, but then I have always used T8 fluorescent or on smaller tanks the CFL bulbs, and I have worked out exactly what I need for my plants and fish, so I stay with it. Makes life simpler.

Byron.

First of all, thank you Byron for replying and being so informative and helpful, secondly, I am a little bit confused with the PAR because the way I understood it was that the PAR was between 400nm-700nm or something, so I thought it was only to do with the spectrum side of things, I didn't really think it had anything to do with CRI, but then I may have misunderstood.

 

[Byron]

First of all, thank you Byron for replying and being so informative and helpful, secondly, I am a little bit confused with the PAR because the way I understood it was that the PAR was between 400nm-700nm or something, so I thought it was only to do with the spectrum side of things, I didn't really think it had anything to do with CRI, but then I may have misunderstood.

I was the one mixed up, for some reason I was thinking CRI when I typed PAR, so forget that bit. Sorry for the confusion.

 

[MyDogSpot]

I was the one mixed up, for some reason I was thinking CRI when I typed PAR, so forget that bit. Sorry for the confusion.

Not a problem mate.