Lighting in tanks

[Marnol D]

Hello,

 

I was looking to upgrade my light for my 45 gallon tall tank. I currently have a NICREW ClassicLED Gen 2 Aquarium Light that is 5200 LUX@12" air  78 PAR@12" in air and 25 W @ 1910lm. Would it be safe to move this over to my 20Long as its new light? Also what would be a good new Higher Par light for my 45 (36.3 in L x 12.6 in W x 23.8 in H) or atleast give a good amount of light to the bottom of my tank?  Should I go with the Fluval for the 40 gallon that is recommended or should I look for another one?   Also is there a Par in air to Par in Water calculator? 

OR should I keep the 45 the same and get a new light for the 20L (which is really the one that needs a new light because its running a NICREW ClassicLED Gen 2 Aquarium Light thats 4100 lux in air, 70 par in air, and 15W @ 1160LM that was made for a 10 gallon tank

 

In the 45 Gallon I run CO2 and have a hodge podge of plants ranging from stemmed moneywort to crypts to amazon swords to monteCarlo and some annubis (always need more annubis though)

 

Edited December 18, 2020 by Marnol D

[Brandy]

I can't really answer all your questions.

I mostly run Nicrew and similar lights. My solution to low light recently is just to double up on the slimline cheap lights for deeper tanks.

I think Par is affected by too many factors to calculate straight across from "in air" to "in water". There may be a way to extrapolate the amount of par drop (caused by backscatter of water) per inch of water, but actual Par will be affected by your specific water clarity, and the albedo effect of your tank--how dark or light your background and substrates are, etc. Without a par meter I take all measurments with a grain of salt, much like MPG.

If I were happy with the lighting in the 45, I would go with an upgrade to the 20, and just get the correct sized cheap light. For the plants in the 45 medium light sounds fine, those aren't demanding plants in general. Then if I felt I needed more light anywhere I would just get another cheap light. This to me has been the most economical and flexible. With wifi plugs I can even tweak the light levels thru the day.

[Mike_M]

For a tank as deep as your 45g with co2 I would use a fluval 3.0 for sure, unless your budget is tight. It's a great light, but they get so bright they can be overkill. In my experience 20 longs don't need ultra bright lights because they are so shallow. But if you are liking the growth you are currently getting in your 45 then just get a cheaper light for your 20L and save some bucks.