What type of lighting should I go with

[Vernon Newlands]

My tank is 90cm X 40cm X 45cm deep. The plants that I grow are easy plants that require low to moderate light and I don't use CO2. Which light should I go with.
1 X 90cm twin row full spectrum.
2 x ROWS FULL SPECTRUM XB LEDS
3W Power LEDS
PAR 134 @ 45cm @ 90°
60W Power
Dimmable, not colour tunable.
or
1 X 90cm triple row full spectrum.
3 x ROWS FULL SPECTRUM XB LEDS
3W Power LEDS
PAR 173 @ 45cm @ 90°
90W Power
Dimmable, not colour tunable.
The first is $234 Aust & the second is $295 Aust.
Both lights can be dimmed.

 

[Edvet]

Whatever you think looks best to your eye, but it's a lot of light, so with low light and no CO2 you'll be dimming the cr@p out of them.

 

[ian_m]

If you don't intend to use CO2, then you really should be looking at only a single T5 HO tube at absolute maximum, even a single tube might be too bright.

Use this graph, to estimate rough light levels and if not using CO2 keep it in the low light region.

Thus for a single T5 tube (and no reflector) you are looking at a tank depth or light height of greater than 24inches (60cm). If your height is less than this you will need to find ways of reducing the light levels, foil rings on the tube, darkened plastic etc.

You will find most T5 LED tubes produce less lumens than a T5 HO fluorescent tube so this is another option to consider.

 

[Vernon Newlands]

The plants that I intend to grow are low to medium light and some are medium to high light. The medium to high I want to grow on the medium to reduce the growth rate and therefore maintenance. The plants that I grow at the moment in a smaller tank are bacopa,Wisteria,Corkscrew Val,Myriophyllum Simulans,hygrophila Polysperma,Red Devil Sword,Crypt Tropica,Anubias, Java Fern,Hairgrass & Ammannia Senegalensis. The plants that I am looking at adding are some of the following Aponogeton Crispus,more crypts & swords,Ludwigia species (arcuata, brevipes, repens, super red, colorata & "H'Ra") & Sturogyne repens.

 

[alto]

Have you seen this lights irl?

Depending on LED array, you likely want a 120cm lens to get decent back to front light distribution ... this won’t happen with a single T5 bulb no matter how outstanding the reflector

Also note that depending on the driver used in the LED assembly, as you reduce power, light spectrum may shift significantly, also width of the light “cone” decreases significantly ... eg, while the three row array of the 90W unit seems it may provide better light distribution, by the time you dim this to meet CO2 availability, actual light intensity & distribution may be less than the two row array 60W unit (also dimmed for this tank setup, but to a lesser degree)

If possible I’d look for a 45W LED, dimmable & colour tuneable - especially if you’ve no plans to add CO2 injection