# 54 litre aquarium - Two compact fluorescent light bulbs



## Joost (27 Feb 2015)

Hi folks,

A friend of mine is about to start an aquarium and is looking for a really cheap method of lighting his aquarium (student). He's aiming for "medium" light, since he'd like to grow a hemianthus callitrichoides carpet (perhaps "high light"?).  The aquarium holds 54 litres of water. The dimensions are as follows: 60 cm x 30 cm x 30 cm (lenght, width, height). He was thinking of using two cool white compact fluorescent (CFL) light bulbs. The CFL bulbs will be mounted vertically through two IKEA TERTIAL desk lamps, as illustrated in the figure below.





http://www.ikea.com/nl/nl/catalog/products/60370183/

He will be using pressurized co2 as well as an up aqua inline atomizer. The substrate is ADA aqua soil. A SUNSUN HW-302b will be used for filtration (cheap, 1000 litres/hour, probably around 500 litres/hour when stuffed with media). Additionally he will be dosing according to the EI method.





https://www.thenutrientcompany.com/aquarium/calculators/ei_calculator/

The final part of the puzzle is the lighting set up. I'm unsure of the amounts of watts he should use for his two CFL bulbs (mounted vertically), therefore I'm looking for advise from you folks. I was thinking around 15 watts each bulb personally, perhaps even 20. The bulbs will not be dimmable since he does not own a dimmer. However, by using the IKEA TERTIAL desk lamps it will be possible to adjust the height of the bulbs.

I'm interested in what you folks would do in his situation. How many watts should he use? Also, please elaborate why you think X amount of watts is the most suitable.

Thanks in advance!


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## EnderUK (27 Feb 2015)

CFL bulbs are fine, the bulbs aren't dimmer-able but you can adjust the height. Light isn't really about power (watts) but par (light intensity) which is adjustable by light energy output and distances. For a new tank you want to start off with low par and short lighting eriod ( 4 hours) and increase gradually over months.


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## Joost (27 Feb 2015)

EnderUK said:


> CFL bulbs are fine, the bulbs aren't dimmer-able but you can adjust the height. Light isn't really about power (watts) but par (light intensity) which is adjustable by light energy output and distances. For a new tank you want to start off with low par and short lighting eriod ( 4 hours) and increase gradually over months.



I am aware of the fact that light should be measured with a PAR meter, but as students we do not have access to this device, since it would be way to expensive to buy. Therefore it is, in our situation, impossible for us to use PAR as a starting point. Existing PAR datatables regarding CFL bulbs would be useable as a starting point, however.

You also say that for a new tank you want to start off with "low" PAR. What exactly is low PAR? I think numbers are a necessity when mentioning PAR, which also relate to watts in some way when it comes to CFL bulbs.

I'm really looking for a clear answer, for example: In my opinion you should use X amounts of watts, as this results in X amount of PAR at substrate level. I recommend to position the CFL X amounts of centimeters above the water level, because .... etc.


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## EnderUK (28 Feb 2015)

Joost said:


> we do not have access to this device, since it would be way to expensive to buy. Therefore it is, in our situation, impossible for us to use PAR as a starting point. Existing PAR datatables regarding CFL bulbs would be useable as a starting point, however.




That's okay someone's done it for you.Clear Answer


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## Joost (28 Feb 2015)

EnderUK said:


> That's okay someone's done it for you.Clear Answer



Hi, this is exactly what I needed, thanks!

Edit: Apparently 15 watt would even be too much since this would result in 80 (!) micromols/m²/s at the substrate (substrate to light source is approximately 42 cm). We're aiming for 35 to 60 micromols of PAR.

Low light - _15-30 micromols of PAR - CO2 is not needed, but is helpful to the plants_
Medium light - _35-50 micromols of PAR - CO2 may be needed to avoid too many nuisance algae problems_
High light - _more than 50 micromols of PAR - pressurized CO2 is essential to avoid major algae problems



 

source: http://www.plantedtank.net/forums/showthread.php?t=184368_


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