Article Shedding Light on Success: A Comprehensive Guide to Aquarium Lighting for Planted Tanks

[Art]

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[Yugang]

Thank you for writing this article @Art .

One suggestion would be to give a bit more colour on how light in the tank can be measured. We don't necessarily need to borrow/rent/buy an expensive PAR meter, but can get very decent indication with a simple app (like Photone) on a iPhone or Android phone.

Post in thread 'PAR meter using iPhone / Android APP - does it work?'

Dec 17, 2023

Wel, actually I don't see a way to edit my previous post, so I'll post here my new findings by using a simple paper diffuser on the iPhone camera.

Here are the new values I got:

Apogee: 50 PAR -----> App: 48
Apogee: 80 PAR (at my tank's substrate) -----> App: 76
Apogee: 100 PAR -----> App: 101
Apogee: 150 PAR -----> App: 148
Apogee: 200 PAR -----> App: 195

So, please forget what I wrote earlier, this app works very well!

I have also remeasured with different colors, and it looks like white light is the best measured, whereas the red light is the worst (measurements are skewed a great...

• fablau

• 

Also it is important to realise that more often than not light intensity varies a lot (like 50% or more within a tank), and that may be relevant for plants at different locations or different depths in the tank. The inverse square intensity law that we may remember from high school can be misleading when estimating light intensity in an aquarium.

Post in thread 'PAR meter using iPhone / Android APP - does it work?'

Mar 17, 2024

For a light point source indeed the intensity goes down by the square of the distance between source and detector. But for a line source (long fluorescent tube or LED bar) this is NOT longer true, it goes down by the distance (rather than distance squared).

I hope it is helpful to elaborate on this again, as light and optics can be somewhat confusing, even counter intuitive and are often misunderstood. Take this thread on another forum where the OP asks:

Par

I've replaced my two t8 fluorescent tubes to two t8 LEDs . The LEDs say the par is 167 at 20cm. If the LEDs are around 50cm above the substrate level would the par drop off alot? There is two of them so they should be ok for a low tech?

www.ukaps.org

Spoiler alert, the correct answer it NOT that we apply the...

• Yugang

• 

In summary, it is seems good advice for beginners and more experienced hobbyists to have a decent estimate of PAR in the tank, while only in very specialist settings, or professional applications, the cost for professional PAR meter would be justified.