# What should photoperiod be?



## Django (Jun 13, 2012)

I did some research and for my setup, a 10gal, and light intensity, the photoperiod should be 10 hours, and I may even be able to go up to 11 hours at some point. My sword isn't doing that good and has green algae on two of the leaves, and I have diatoms which spread, I think, when I tried 11 hours.

I'm thinking that the plants all have to be well-established and using lots of light before I can put up the photoperiod and they might grow faster.


----------



## morgan (Apr 4, 2012)

I used 8 hrs when i first planted my tank , couple of months into it i upped to 10 hrs . I managed to get away with any sort of algae bloom.

CO2 must be adjusted also if used.


----------



## hbosman (Oct 5, 2006)

I keep mine at 8 hours just to keep the trimming to once a week. I guess if you need the tank to fill in, 10 hours a day is reasonable.


----------



## Fdsh5 (Jan 3, 2012)

I run my tanks 4 hours on, 4 hours off then 4 hours back on. It has kept the algae growth in check and allows me to see the tank lit at night when I get home from work. I didn't notice any difference in plant growth when I switched the light hours.


----------



## PaulG (Oct 10, 2010)

If 10 hours gives you good growth and no algae then go for it. If you're happy how it is, don't change it.

8 hours will of course be slightly better for your electric bill.


----------



## toffee (Apr 2, 2007)

Wondering why submerged plants need longer hours of light? Even plants need full sun can thrive with 5-6 hours of sun.


----------



## PaulG (Oct 10, 2010)

They don't need longer hours. You can grow submerged plants at 4/5 hours.

My current tank is on a 6 hour photoperiod. 1pm - 7pm.


----------



## toffee (Apr 2, 2007)

PaulG said:


> They don't need longer hours. You can grow submerged plants at 4/5 hours.
> 
> My current tank is on a 6 hour photoperiod. 1pm - 7pm.


That's so against the conventional wisdom though, folks all preach for 10 hours, with 8 hours as the absolute minimum.

I believe it all came from assuming aquaplants were from the tropics and being right on the equator, they receives 10-12 hours of tropic sun? That being said, are all plants from those region? 

If they were to get only 5 hours of sun oooops light, will they grow slower and smaller or they will wilt and die? 

How about 5 hours of super bright vs 7.5 hours of medium bright vs 10 hours of low?


----------



## pejerrey (Dec 5, 2011)

Lol, mine gets a maximum of 6hrs. Now is on 4hrs. It all depends of your tank and your method, IMO.










This one gets about 8hrs:










And I have a small betta tank that gets 9-10hrs.


----------



## ramen lover (Jun 22, 2012)

mine get 6 or 7 during the day, then when i get home i turn it on again so i watch it.. and i leave it for about 2-3 hours


----------



## toffee (Apr 2, 2007)

pejerrey said:


> [Lol, mine gets a maximum of 6hrs. Now is on 4hrs. It all depends of your tank and your method, IMO.


4 hours and this tank is beautiful. Care to explain "depends on your tank and method?



pejerrey said:


>


----------



## pejerrey (Dec 5, 2011)

toffee said:


> 4 hours and this tank is beautiful. Care to explain "depends on your tank and method?


 Thank you very much 

I would gladly explain a bit my take on this complex subject of light within the context of this set up. 

This is a link to this tank's method:
http://www.plantedtank.net/forums/showthread.php?t=183530

Been that light is the most important driving force in dictating the "metabolism" of a tank, adjusting it will dictate what method can/should be applied. 

I'm convinced that same plants could be grown with less intense light with a longer photoperiod and maybe less nutrients/co2.

I have powerful lights in this tank, 2x T5HO 22" (~50PAR @ substrate level). If I have a longer photoperiod I would need more concentration of available nutrients and co2. This conflicts with cardinias shrimp. 

So, for the plants to process the available nutrients without a higher concentration of co2 I need a shorter photoperiod with this lights. If I want a longer photoperiod, I will need more co2 (or raise the fixture which would look ugly) to outcompete algae. Nutrients will be processed either way, it's just a matter of who has better conditions, plants or algae.

The general consensus is that algae issues are a consequence of lack of co2. From my point of view is caused by excess of light, therefore the need for more co2. 

As I can't (or don't want) dose more co2, I must reduce the amount of light. And as I don't want to raise the light fixture to reduce its intensity, then I must shorten the photoperiod.

I hope this is clear enough.


----------



## toffee (Apr 2, 2007)

Hey pejerrey, nicely explained. For the fun of discussion. let's see if we can make 3 assumptions:


Strong light - short duration. In your case ~50PAR x 4 hours. So within those 4 hours, the plants absorb as much CO2 and other nutrient as available, ie out completing algae for 4 hours. Rest of the time, not enough light for the plants or algae. Apparently your plants have been thriving on 4 hours of "food" and enjoy being inactive for the other 20 hours. Algae was defeat cause out competed when there's light.

Let's call this the eat fast then sleep a lot method.
.
Low light - longer duration. One wonders if you would to lower the light to say ~25 and do 8 hours, what will happen? Can the plants have enough to eat during those 8 hours? Will being low light tilts in favor of algae?

Let's call this the eat slowly then sleep less method.
.
Strong light, long duration. Easy to understand CO2 and other fert in great extra demand here as the plants are running supercharged. 

Let's call this the super growth comes with high maintenance method.

LOL, what do you think? 

Personally, I prefer your method as my daily schedule will only allow me to be in front of the tank for 4 or less hours. Keepinf the lights on when I am not only make sense if the plants absolutely need it.


----------



## pejerrey (Dec 5, 2011)

Thanks! Yeah, make sense!

Once upon a time I wrote this analogy:

..."If we compare the planted tank to the human body:

Light is like hunger, co2 is like exercise, nutrients are food, algae is like fat, plant deficiencies are like disease, plants are like muscles.

Lack of good food (hungry), No exercise makes me prone to disease. ( no co2=plant deficiencies/some algae)

Too hungry, eat a lot, not enough exercise, I get fat. (high light, high nutrients, no co2 = algae bloom)

Too hungry, eat a lot, exercise a lot, I'm muscle man. Very healthy. (high light, plenty of nutrients, plenty of co2 = healthy lush tank)

Not too hungry, eat lean, exercise just enough, I'm in good shape. Good health. (low light, enough nutrients, little to no co2 = nice planted tank, limited species and slow growth)"....




Edit: One thing I forgot I mention is that in that tank I have the light in two blocks of 2 hrs(2on,3off,2on,17off). And I had it on 6hrs total for months. Just recently went 4 total.

There is indirect sunlight. So some photosynthesis is happening during the day.


----------



## pejerrey (Dec 5, 2011)

Imagine my tank is a puddle in a creek in between trees and gets just that amount of direct sun light during the day with only shade the rest of the day.


----------

