Lighting question - clueless!

[squidneh]

I have a 20 gallon long, so it is a pretty shallow tank. I have this light for it and would like to use it if possible.
https://www.amazon.com/gp/product/B07788TVG9/?tag=ff0d01-20

I realize it may not be the best light for growing plants - but since I already have it I would like to try to make it work. It says it has 36 .5 watt LEDs. So that means 18 watts. I've never used LED lighting before (was my sister's set up) so I'm not sure how sufficient it will be for growing plants. I potentially could purchase a second one for the tank if that would help.

If I was using this light, what type of lighting would I have? Low? Too low for plants? Wrong type of lighting? Sorry, I'm clueless about this LED stuff. I did okay with my T8 set up when I had my big tank, but mostly by luck.

Should I be considering using fertilizers or root tabs?

Thanks in advance!

 

[Byron]

This is not particularly good light for freshwater planted tanks. Some shade/slow-growing plants might manage with a struggle, but I would not expect it.

First problem is spectrum. The colour temperature of light is measured in degrees Kelvin. The lower the K the "warmer" (meaning, more red, less blue in the light mix) the light, while the higher the K the "cooler" (meaning more blue, less red). Mid-day sun is in the 6000K range. So this light is 10,000K which is very cool, and actinic is the same. This light is good for marine tanks with corals.

Plants need red and blue light to drive photosynthesis, and of the two, red is the more important. Adding green to the red and blue improves things. Light with a K between 5000K and 7000K will provide this; many "daylight" tubes/bulbs have 6500K which is good light.

The second thing is intensity, but without the right spectrum this will tend to induce algae.

I am still using T8 fluorescent (except over my 10g and 20g where I have an incandescent fixture with two 9w CFL bulbs of 6500K) and the 6500K tubes are very good light. I tried several LED fixtures when one of my T8's gave out, but all went back to the store and I ended up repairing the T8 by removing the works and inserting a shop light into the housing.

Over a 20g long, you could use a 24-inch T8 fluorescent; Aqueon still make these for their 29g tanks (same length and width).

Byron.

 

[squidneh]

Thanks for the insight!

I was afraid it wouldn't be very good for plants. I don't have much of a budget to buy new lighting, and the only light I have right now is 48" so that won't do. Bah.

 

[neoyyf]

You might be able to get away with buying one or two clip on lights and fit LED bulbs with standard fittings. As long as it has the correct Kelvin and enough intensity, you should be able to grow easy and perhaps some medium plants with fertilisers and perhaps Liquid Carbon if budget doesnt allow for a CO2 system. However, if you dont make a diy hood or reflector, it will make the room very bright

 

[Toney]

You can pry the diffuser off the led lights

I've got two 5w bulbs over my two newest setups, gonna see.

All I could find locally were 5k... they seem to be working