# Photo-period duration Vs light intensity (PAR)



## Jester946 (Mar 30, 2013)

I have come across a lot of people's opinions of what a duration to run your lights, and I personally have my photo period for 10 hours a day. A single block, without a break in the middle like some do. I keep my PAR level, at the substrate, in the 35-40 range. I still have some algae, usually on rocks I get a little BBA, and occasionally on the top of my drift wood I get some BBA as well.

My question is, with higher PAR at the substrate, say, 60-70, would a shorter photo period compensate for the much, much higher PAR?

I know as PAR goes up, CO2 needs to as well...if I am at 30-40ppm CO2, what PAR is acceptable at my substrate? Will I ever get away from slight BBA build up on my rocks?


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## Jester946 (Mar 30, 2013)

Also, how do people manage to grow such BEAUTIFUL mosses, and other slow growers more towards the top of the tank (On top of driftwood, rocks etc...) and not have algae? Are they setting their PAR to the top of the tank, and not worried about ground cover getting high light? It seems with my PAR set to 35-40 at the substrate, my then tall plants and moss towards the top of the tank become exposed to algae...And this is with again, 35-40ppm of CO2....


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## jeffkrol (Jun 5, 2013)

Jester946 said:


> I have come across a lot of people's opinions of what a duration to run your lights, and I personally have my photo period for 10 hours a day. A single block, without a break in the middle like some do. I keep my PAR level, at the substrate, in the 35-40 range. I still have some algae, usually on rocks I get a little BBA, and occasionally on the top of my drift wood I get some BBA as well.
> 
> My question is, with higher PAR at the substrate, say, 60-70, would a shorter photo period compensate for the much, much higher PAR?
> 
> I know as PAR goes up, CO2 needs to as well...if I am at 30-40ppm CO2, what PAR is acceptable at my substrate? Will I ever get away from slight BBA build up on my rocks?


buy some Olive Nerite snails.. best algae janitors in the world.. and they can't reproduce (though they try) in FW............


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## jeffkrol (Jun 5, 2013)

Jester946 said:


> Also, how do people manage to grow such BEAUTIFUL mosses, and other slow growers more towards the top of the tank (On top of driftwood, rocks etc...) and not have algae? Are they setting their PAR to the top of the tank, and not worried about ground cover getting high light? It seems with my PAR set to 35-40 at the substrate, my then tall plants and moss towards the top of the tank become exposed to algae...And this is with again, 35-40ppm of CO2....


Plants have to out-compete algae w/ CO2 and nutrients.. The light break thory is based on the other "facT" that plants can start photosynthesis faster than algae.. so they win out over it when you "pulse" the photo period..

I suspect "some" algae is always present.. no matter what.


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## gus6464 (Dec 19, 2011)

Jester946 said:


> I have come across a lot of people's opinions of what a duration to run your lights, and I personally have my photo period for 10 hours a day. A single block, without a break in the middle like some do. I keep my PAR level, at the substrate, in the 35-40 range. I still have some algae, usually on rocks I get a little BBA, and occasionally on the top of my drift wood I get some BBA as well.
> 
> My question is, with higher PAR at the substrate, say, 60-70, would a shorter photo period compensate for the much, much higher PAR?
> 
> I know as PAR goes up, CO2 needs to as well...if I am at 30-40ppm CO2, what PAR is acceptable at my substrate? Will I ever get away from slight BBA build up on my rocks?


I have been trying that on my tank. I have my tank on an 8 hour photoperiod:

2 hour ramp up
4 hour max power
2 hour ramp down

This is the PAR I am pushing in max power

Bottom: 150
Middle: 600
Top: 900

Algae: 0

I have my co2 cranked to yellow and 2 hours after being on max power it's pearling bonanza until lights turn off. No issues so far.

I have some algae on my rocks that my amanos keep in check.


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## TexasCichlid (Jul 12, 2011)

jeffkrol said:


> buy some Olive Nerite snails.. best algae janitors in the world.. and they can't reproduce (though they try) in FW............


I find that oto cats are pretty much unbeatable in terms of cleanup fauna. I am not nearly as impressed with the nerites I have, as they do not do nearly as good of a job. Also, the egg laying is annoying. BN plecos are also nice but tend to be quite a bit more aggressive with substrates.

35-45 PAR at substrate is fine and can grow most hobby plants easily with CO2. If you are getting BBA, you need to turn up your CO2 and/or improve flow by redirecting flow to where you are getting BBA or increasing flow overall. If you are battling BBA with 35-45, increasing PAR is not the answer.


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## Jester946 (Mar 30, 2013)

jeffkrol said:


> buy some Olive Nerite snails.. best algae janitors in the world.. and they can't reproduce (though they try) in FW............


I'm not going to try and patch an issue with lighting with a bandaide. Nerites are annoying from the egg spots they leave on everything. 




jeffkrol said:


> Plants have to out-compete algae w/ CO2 and nutrients.. The light break thory is based on the other "facT" that plants can start photosynthesis faster than algae.. so they win out over it when you "pulse" the photo period..
> 
> I suspect "some" algae is always present.. no matter what.


People took this as fact years ago, but from what I have read from Tom Barr, this is incorrect.


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## Jester946 (Mar 30, 2013)

gus6464 said:


> I have been trying that on my tank. I have my tank on an 8 hour photoperiod:
> 
> 2 hour ramp up
> 4 hour max power
> ...


You're at 150 PAR at the substrate?

What is your co2 PPM based on KH and PH?


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## Jester946 (Mar 30, 2013)

TexasCichlid said:


> I find that oto cats are pretty much unbeatable in terms of cleanup fauna. I am not nearly as impressed with the nerites I have, as they do not do nearly as good of a job. Also, the egg laying is annoying. BN plecos are also nice but tend to be quite a bit more aggressive with substrates.
> 
> 35-45 PAR at substrate is fine and can grow most hobby plants easily with CO2. If you are getting BBA, you need to turn up your CO2 and/or improve flow by redirecting flow to where you are getting BBA or increasing flow overall. If you are battling BBA with 35-45, increasing PAR is not the answer.


I wonder where my short fall is, then. I am injecting 35-40ppm of CO2 in to my tank....Already my two rams are upset near the end of my photocycle, they are hiding and biding time until the lights/co2 die. 

Will having the co2 and light on separate timers, and having the co2 come on before the light help with this?


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## jeffkrol (Jun 5, 2013)

Jester946 said:


> I'm not going to try and patch an issue with lighting with a bandaide. Nerites are annoying from the egg spots they leave on everything.


I must be lucky.. The nerites occasionally lay eggs.. A few days later.. gone.. 
All I know is that 30 of them "cleansed" a 40gal algae farm in a week.. 
THAT was impressive...
Why do you think agae is strictly a lighting issue?? Seems to have a lot more involved than that.. Like nutrients..




Jester946 said:


> People took this as fact years ago, but from what I have read from Tom Barr, this is incorrect.


Link?? I'd be interested to read it.......


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## Jester946 (Mar 30, 2013)

jeffkrol said:


> I must be lucky.. The nerites occasionally lay eggs.. A few days later.. gone..
> All I know is that 30 of them "cleansed" a 40gal algae farm in a week..
> THAT was impressive...
> Why do you think agae is strictly a lighting issue?? Seems to have a lot more involved than that.. Like nutrients..


Because EI dosing seems to remove the idea from it being caused by nutrients. And leave it to light, and CO2 to cause things. 



> Link?? I'd be interested to read it.......


Barrreport.com


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## jeffkrol (Jun 5, 2013)

Jester946 said:


> Because EI dosing seems to remove the idea from it being caused by nutrients. And leave it to light, and CO2 to cause things.
> 
> 
> 
> Barrreport.com



You got me curious.. anyways maybe some food for thought:
http://fins.actwin.com/aquatic-plants/month.200205/msg00047.html

I suspect your CO2 levels are too high and is shifting from a "good thing" to a "bad thing" re: of light.... but purely speculation.. never good to asphyxiate fish either
http://www.google.com/url?sa=t&rct=...=tylUQEJxdliN2TX-Rqufdg&bvm=bv.50310824,d.dmg


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## Jester946 (Mar 30, 2013)

jeffkrol said:


> You got me curious.. anyways maybe some food for thought:
> http://fins.actwin.com/aquatic-plants/month.200205/msg00047.html
> 
> I suspect your CO2 levels are too high and is shifting from a "good thing" to a "bad thing" re: of light.... but purely speculation.. never good to asphyxiate fish either
> http://www.google.com/url?sa=t&rct=...=tylUQEJxdliN2TX-Rqufdg&bvm=bv.50310824,d.dmg



The 2nd article lost me completely when it went with the "global warming problem".

Please keep that stuff out of this thread.


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## gus6464 (Dec 19, 2011)

Jester946 said:


> You're at 150 PAR at the substrate?
> 
> What is your co2 PPM based on KH and PH?


I don't know as I have never measured it. I just pump the CO2 until my drop checker is yellow. I have stopped counting bps because I can't, too many bubbles. I do break the surface with my canister outlets though just in case and CO2 is cheap.

But yes, my HC gets 150 PAR.


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## Jester946 (Mar 30, 2013)

gus6464 said:


> I don't know as I have never measured it. I just pump the CO2 until my drop checker is yellow. I have stopped counting bps because I can't, too many bubbles. I do break the surface with my canister outlets though just in case and CO2 is cheap.
> 
> But yes, my HC gets 150 PAR.


K. Drop checkers aren't as accurate as I like, so I stay away from them.

BPS isn't too accurate as well, as every tank is different.

My first change will be running my CO2 separate from my photo period by a 1/2 hour, and see what effect that has.


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## gus6464 (Dec 19, 2011)

Jester946 said:


> K. Drop checkers aren't as accurate as I like, so I stay away from them.
> 
> BPS isn't too accurate as well, as every tank is different.
> 
> My first change will be running my CO2 separate from my photo period by a 1/2 hour, and see what effect that has.


My CO2 turns on 2 hours before my lights come on and turns off 2 hours before lights out.


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## Jester946 (Mar 30, 2013)

gus6464 said:


> My CO2 turns on 2 hours before my lights come on and turns off 2 hours before lights out.


Thank you for the information. I am going to set this up this evening.


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## TexasCichlid (Jul 12, 2011)

My CO2 comes on 1 hour before lights, turns off 30 minutes before. Two hours prior and I was having gassing issues.


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## Hunter P (Aug 6, 2013)

just put your lights down to 8 hours a day


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## Hoppy (Dec 24, 2005)

There is no way accessible to hobbyists to measure CO2 accurately enough to say you have 35-40 ppm of CO2. At best you might be able to say you have 15-40 ppm. It seems to be the consensus today that it is best to just use the plants and fish to "measure" the CO2. Raise the bubble rate a small amount, watch the fish for distress, watch the plants for improved growth/pearling. Repeat until you reach the optimum bubble rate. Maybe some day we will have an affordable CO2 meter that lets us measure CO2 ppm, but that is in the future, at best.

Your question about PAR vs light duration doesn't appear to have a definitive answer. For sure, there is a minimum PAR that each plant needs to grow, and longer photoperiod doesn't substitute for that minimum PAR. And, some people believe that a split photoperiod helps deter algae growth, but I haven't seen any test results that confirm that. In low light, non-CO2 tanks, a split photoperiod can help by allowing time for more CO2 to be generated from decomposition in the substrate, so the plants don't run out of CO2 in the middle of the photoperiod.


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## Jester946 (Mar 30, 2013)

Hoppy said:


> There is no way accessible to hobbyists to measure CO2 accurately enough to say you have 35-40 ppm of CO2. At best you might be able to say you have 15-40 ppm. It seems to be the consensus today that it is best to just use the plants and fish to "measure" the CO2. Raise the bubble rate a small amount, watch the fish for distress, watch the plants for improved growth/pearling. Repeat until you reach the optimum bubble rate. Maybe some day we will have an affordable CO2 meter that lets us measure CO2 ppm, but that is in the future, at best.
> 
> Your question about PAR vs light duration doesn't appear to have a definitive answer. For sure, there is a minimum PAR that each plant needs to grow, and longer photoperiod doesn't substitute for that minimum PAR. And, some people believe that a split photoperiod helps deter algae growth, but I haven't seen any test results that confirm that. In low light, non-CO2 tanks, a split photoperiod can help by allowing time for more CO2 to be generated from decomposition in the substrate, so the plants don't run out of CO2 in the middle of the photoperiod.




Thank you Hoppy for spelling all of this out.

I did change my timers, so I have co2 coming on 1 hour before the lights, and shutting off 1 hour before the lights.


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## Jeff5614 (Dec 29, 2005)

Jester946 said:


> I wonder where my short fall is, then. I am injecting 35-40ppm of CO2 in to my tank....Already my two rams are upset near the end of my photocycle, they are hiding and biding time until the lights/co2 die.
> 
> Will having the co2 and light on separate timers, and having the co2 come on before the light help with this?


If your fish are having issues with CO2 then you're injecting too much CO2 or have a lack of O2 in the tank which is what I would suspect. You need to increase your oxygenation. Increasing surface agitation is probably the easiest way while at the same time being sure you have adequate circulation in the tank. Yes, it may cause you to lose a small amount of CO2, but all you need to do is to increase your bubble count a bit to compensate. O2 and CO2 exist independently. You can have good levels of each with no need to sacrifice one for the other.


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