Lighting help - do I have enough?

[Pellington]

Hi all,

I have read online that for a planted tank I need between 20 and 40 lumens per litre of water to keep medium difficulty plants, and 40+ lumens p/litre for hard plants.. I have a 300L tank, and so using the above formula i would need a light unit which produces 6000 - 12000 lm.

My lighting unit is a 59w Fluval LED unit which produces 4250 lm at a colour temperature of 6500K.

So, simple maths tells me I do not have anywhere near enough, but before I shell out on another unit I wanted to get everyone's thoughts on whether this lumens p/litre guideline was correct/accurate?

It's worth noting that some of my plants are turning brown and I have been getting advice on another thread (https://www.fishforums.net/threads/dwarf-ambulia-turning-brown.477347/) that it could be lighting related, hence wanted to dig a bit deeper into the lighting discussion here.

Thanks !

 

[FF_Member146894]

PAR is a far better indicator of light intensity than "lumens per liter"
you can search the internet for PAR for your model of light, which I assume is a fluval plant 3.0?
take into account the height and width of your tank with the possible light intensity decrease when you get further from the center of the light (which is why you keep 2 full light units on 24"+ wide tanks)

also, if you increase light intensity you have to balance other factors by increasing the amount of fertilizer and maybe consider adding a CO2 injection system
if you don't balance your lighting, nutrients, and CO2 levels, you will give an opportunity for unwanted things to appear such as various forms of algae

 

[Sgooosh]

PAR is a far better indicator of light intensity than "lumens per liter"
you can search the internet for PAR for your model of light, which I assume is a fluval plant 3.0?
take into account the height and width of your tank with the possible light intensity decrease when you get further from the center of the light (which is why you keep 2 full light units on 24"+ wide tanks)

also, if you increase light intensity you have to balance other factors by increasing the amount of fertilizer and maybe consider adding a CO2 injection system
if you don't balance your lighting, nutrients, and CO2 levels, you will give an opportunity for unwanted things to appear such as various forms of algae

ooh yeah this is very true especially the algae part. once i had a super bright photography light on my fish tank, and that made algae blossom