Photoperiod

Panda

Guru Class Expert
Jun 14, 2008
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Hi
I have a question about adjusting the light period on my tank

It's a 90 gallon discus planted tank using EI and CO2. Currently I have the lights on a timer for 8 am to 10 pm for one set of lights ( 2x 65 watts) and another set with the same amount from 2 pm to 10pm. I think that this strong and extended period is the factor for some BBA and other algae- not much.

Is this new period better for plants and help me with the algae?
Set 1 from 8 am to 10 AM ( just 2 hours) with CO2 from 7:30 am until 9 pm
then
Set 1 from 1 pm to 10 pm with
set 2 from 5 pm to 9 pm

During the day the sun enters from a window and the tank receives some of that- so I think it won't affect that the CO2 is still on for this 3 hours between 10am and 1pm---but I'll keep and eye during the weekend--
The reason for more light during the afternoon and night is to be able to enjoy the tank after work without loosing plants.

Any comments or suggestions ?
 

Mooner

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Jun 9, 2006
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Consider CO2 on at 9:00 am, lights on at 10:00 am to 8:00 pm (10 hrs) and CO2 off at 7:00 pm. If you wish to view the tank later than this adjust the schedule ahead accordingly.
 

VaughnH

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Jan 24, 2005
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260 watts is a lot of light for a 90 gallon tank, unless they are suspended quite a ways above the tank. You could try the noon burst plan - run one light for the entire 8 hours the lights are on, and add the other light for the middle 2 to 4 hours. You can also use a split photo period to be able to enjoy the tank early in the morning and late at night without having such a long photoperiod. I'm not sure how you would do this with the noon burst, but someone probably can recommend something.
 

Panda

Guru Class Expert
Jun 14, 2008
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Puerto Rico
Thanks for all your advices !!

Here's what I did:

CO2 : on at 11:30 am until 9 pm ( DC green to yellow-fish are OK )
Set 1 of lights ( 130 watts ) from 12:00pm to 10 pm (10 hours)
Set 2 of lights (130 watts) from 6:00 pm to 10 pm

Is this OK? more/less ? :eek:
 

Gerryd

Plant Guru Team
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Sep 23, 2007
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Hi,

How about the following:

Set 2 of lights (130 watts) from 5:00 pm to 8 pm for a shorter burst and will be over closer to when the c02 is off.......

OR

Keep your set 2 duration/timings but REMOVE on the the tubes on this bank. This is still an increase of 50% for your noon burst..

OR

I have digital timers that have a dual setting. Since I want to view more at night and have only 1 light switch, I give a short siesta period as follows:

c02 on: 11:30 am
Lights on 1:00 pm
start of siesta
Lights off 5:30 pm
Light on 6:15 pm
end of siesta
c02 off 10:30 pm
Lights off 11:30 pm

Here in FL, there are many days when it rains at this exact time, so this coincides somewhat with a natural cycle.

I am concerned about going longer than this for the possible detrimental effect on the plants, but assume that they can adapt over time (I have been doing this for > 1 year now), and that shadow/light/rain/cloudiness cycles occurs in nature...... I can live with 45-60 minutes or so and apparently so can my plants...

I have seen no ill effects on plant growth that I am concerned about.
 

Panda

Guru Class Expert
Jun 14, 2008
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Thanks Gerry !

I like the first option.

Correct me if I'm wrong: I don't know where or who told me that for a better control of algae is good to have all the lights off for one or two hours during the day.That the plants can handle this but not algae. Is this right? This is like the cycles you mentioned
 

Gerryd

Plant Guru Team
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Sep 23, 2007
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I think it is the other way around. Algae can recover/adjust more quickly than higher plants.

I think that algae is the reason that a siesta is not recommened.
 

VaughnH

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If I remember correctly, Tom's last comment about siesta periods is that they don't do any good, but also don't seem to do any harm. So, it appears that a siesta should only be used to get viewing periods farther apart than you could have without the siesta.
 

Hilde

Junior Poster
Sep 16, 2008
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2WPG on the WPG rule is 2WPG of T12 lighting. IMO T5HO will give the equivalent of double this rule.

So what type of lights do you have?
 

VaughnH

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Another factor we usually neglect to consider is how high the light is above the substrate. The higher the light is above the substrate, the more light intensity you need to get the PAR values needed at the substrate. So, when we talk about 2 watts per gallon, or whatever number we want to use, we should also say "when the bulbs are about 2-3 inches above the water and with a tank of standard geometry", and, of course, we should add, "for bulbs comparable to AH Supply PC bulbs with AH Supply quality reflectors." I think T12 bulbs would require more than 2 watts per gallon, perhaps about 3 watts per gallon to be equivalent.