Question about lighting

mexicatz

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Feb 10, 2015
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I received the par data from finnex for my planted plus at 13 inches which came in at 62 par. I use a piece of window screen to cut the par by about 40% based on others testing. This puts my par at about 37 at the substrate.

Some of the plants that I have in the 37 par are starting to grow algae while plants in the shade show no deficiencies or algae. I was wondering if it would be better to add another screen to cut the par to about 23 or if increasing my excel dosage to 1.5-2x would solve the problem. 37 par seems pretty close to the safe range to avoid algae with low light so I'm not sure.
 

Phishless

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How long is the photoperiod?

Cutting PAR in a low light tank will reduce algae.
Is raising the light an option?
Glut/excel is a decent algaecide too.

Ever considered adding CO2?
 

mexicatz

Junior Poster
Feb 10, 2015
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How long is the photoperiod?

Cutting PAR in a low light tank will reduce algae.
Is raising the light an option?
Glut/excel is a decent algaecide too.

Ever considered adding CO2?
the photo period is 6-6 1/2 hours and right now i've added the second piece of window screen so I think the par is around 22.
I've looked at some led raisers that raise the light 3,4, or 6 inches but the par would be very close to what I can achieve with the window screen.

Do you think I should stay at the 22? or should I try 37 with 1.5-2x excel dosing

I've considered co2, but it probably wouldn't be a realistic option while I live with my parents.
 

Jason King

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I've always used Hoppy's ( @VaughnH ) reference for par values and if we need co2 based on that par.. low, medium, high light.

Here is a quote from Hoppy.

I don't believe there is any consensus about the definition of low, medium and high light. But, here is my definiition, subject to, and almost certain to change:

  • Low light - 15-30 micromols of PAR - CO2 is not needed, but is helpful to the plants
  • Medium light - 35-50 micromols of PAR - CO2 may be needed to avoid too many nuisance algae problems
  • High light - more than 50 micromols of PAR - pressurized CO2 is essential to avoid major algae problems

Off topic but it would be great if he wrote a updated version of his great lighting article here on the Barr report ;) hint hint :D
 
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VaughnH

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I suggest considering this set-up/method: http://www.aquaticplantcentral.com/forumapc/general-aquarium-plants-discussions/133058-diy-co2.html

No, I don't plan to update my lighting article in the near future. That was a lot of work, spread over a lot of weeks, and I don't collect lighting data for newer light fixtures now. I still think the basic facts in the article are correct, even if the charts of PAR for various types of lighting are obsolete.

I'm now pushing the idea of borrowing a PAR meter to get a relatively accurate reading of the actual PAR you have at the substrate, with your specific lighting and set-up. To make that easier I am loaning out a PAR meter at a reasonable cost - shipping and insurance only. See: https://barrreport.com/threads/apogee-par-meter-for-rent.14334/