# light period for low tech 75gal



## beznsarah (Aug 1, 2006)

How long should the lights be on for a low tech 75 gal? Tank was newly planted 2.5 wks ago. I currently have 1.5wpg of ho T5 with tek reflectors. I'm currently doing 12 hrs. Seems to be doing ok but I am getting a bit of hair algae. I'm adding more fast growing stem plants to try to combat that this weekend.


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## trenac (Jul 16, 2004)

I have always found 12 hours to be to much for my tanks. I would reduce it down to 10 hours daily and see how that works for you.


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## bigstick120 (Mar 8, 2005)

I would start at 9 hours and work your way up, 9 seems to work well for me


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## beznsarah (Aug 1, 2006)

Ok, I'll lower my photoperiod. Now how do I know if I need to increase it, any particular signs to look for?


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## MatPat (Mar 22, 2004)

beznsarah said:


> Ok, I'll lower my photoperiod. Now how do I know if I need to increase it, any particular signs to look for?


What type of plants do you have in the tank? I'm assuming your setup has two 54w HO T-5 lamps, I think I would call that a medium light tank. You are using CO2 with this setup aren't you? Remember, the Watt Per Gallon rule was created back in the day when normal output T-12 tubes (40W) were the type of lighting that was available  The T-5 lamps are much more efficient and give off a more intense that the T-12 lamps.

Are the lamps suspended above the tank or resting on their legs slightly above the tank? One of the SWOAPE members is using 2x54w HO T-5 setups on his 75g tanks and is getting great results!

Now, to try and answer your question, certain plants (most of the Rotala and the Limnophila species) will close up their leaves when they have had enough light for the day. That is an indicator that you have enough light on your tank. In my tank, with 110w of PC lighting and 96w of T-8 lighting, this happens at the 8-10 hour period.

As far as the algae, start attacking it now! Do not give it a chance to spread any more. If you are getting algae in the tank you either do not have enough CO2 in the tank or enough macros. More plants will be a help if you have enogh macros but adding more plants and not increasing your fertilizing (CO2 is a macro) may make the algae worsen.


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## beznsarah (Aug 1, 2006)

see responses below:



> What type of plants do you have in the tank? I'm assuming your setup has two 54w HO T-5 lamps, I think I would call that a medium light tank. You are using CO2 with this setup aren't you? Remember, the Watt Per Gallon rule was created back in the day when normal output T-12 tubes (40W) were the type of lighting that was available  The T-5 lamps are much more efficient and give off a more intense that the T-12 lamps.


Right now the plants I have are mainly hornwort & Java fern. I believe that's part of my algae prob with not enough fast growing plants and too much Java fern. This weekend I will be adding about 60 stems including Hygro's, water sprite etc. I think that will def help w/ the algae to out compete it.

I do have 2x54w bulbs as you assumed.

I'm not using c02, i'm taking a low-tech approach.



> Are the lamps suspended above the tank or resting on their legs slightly above the tank? One of the SWOAPE members is using 2x54w HO T-5 setups on his 75g tanks and is getting great results!


The lights are resting on their legs slightly above the tank. I also have a glass canopy.



> As far as the algae, start attacking it now! Do not give it a chance to spread any more. If you are getting algae in the tank you either do not have enough CO2 in the tank or enough macros. More plants will be a help if you have enogh macros but adding more plants and not increasing your fertilizing (CO2 is a macro) may make the algae worsen.


I will be beginning the dosing soon although it will be much less than the typical co2 setup.

Thanks for your tips !


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## MatPat (Mar 22, 2004)

beznsarah said:


> Right now the plants I have are mainly hornwort & Java fern. I believe that's part of my algae prob with not enough fast growing plants and too much Java fern. This weekend I will be adding about 60 stems including Hygro's, water sprite etc. I think that will def help w/ the algae to out compete it.


More plants will definately help in your setup 



beznsarah said:


> I do have 2x54w bulbs as you assumed.


I still would consider this medium light and on the edge, if not over, needing CO2. Those lights are much more intense than most folks imagine. Like I said, a fellow SWOAPE member is using them and when his CO2 levels get too low (i.e. clogged filter or empty CO2 tank) he gets algae.



beznsarah said:


> I'm not using c02, i'm taking a low-tech approach.


 If you are taking a low tech approach, you may want to see about lowering your light output somehow or at a minimum adding some Excel.



beznsarah said:


> The lights are resting on their legs slightly above the tank. I also have a glass canopy.


Adding some floating plants may be good as would raising the lights higher above the tank. You have a good deal of light on the tank even though the wattage doesn't say so 



beznsarah said:


> I will be beginning the dosing soon although it will be much less than the typical co2 setup.


Take a look at this for dosing a non-co2 tank. It may help you out a bit.


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## beznsarah (Aug 1, 2006)

I'll keep the light thing in mind. I might suspend them above the tank, was considering that to begin with and have an open tank.

Thanks for the link, that's actually the blueprint that I was trying to follow with my tank although I haven't started the dosing yet


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## MatPat (Mar 22, 2004)

beznsarah said:


> ...although I haven't started the dosing yet


This is probably the #1 reason why you are getting algae. 2.5 weeks with your light level is a long time to go without ferts! Plants need their nutrients just like we do. If you got them from another hobbyist they may be able to fall back on stored notrients but if you purchased them from your local LFS. they were probably nearly starving to begin with


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## beznsarah (Aug 1, 2006)

Wow, didn't know they were that important if since I did put the peat moss under the gravel, I guess that would just mainly provide Carbon though. I've ordered some with someone else, I just need to go pick them up, I guess i'll do that this weekend


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