View Full Version : Lighting question

07-25-2009, 03:46 PM
I ready somewhere that sometimes if you already ahve a nuisance green hair algae problem in your tank that in order to get rid of it you need to up the size and brightness of your bulbs on scrubber to rid the problem and then go back to recomended size needed. Well I went to home depot and bought an R40 light with 1100 lumens and only 3500k It was recomended that I use 5100k Home depot doesn't have 5100 but they do have 5000k Question: Should I go back and get the two 5000 k bulbs or do I move up since i have a green hair algae problem. 27 watt? what am I changing when i move up. the brightness or watss? Recomendations on what I should put in there? Round abouts? For now at least until i get the green hair under control......... Then i will go back to the 23w r40 5000k that they carry unless it's important to have the extra 100k that they recomend (5100k) If that is the case i'll need to go elsewhere for bulb. I would think later that the 5000k would be ok. Anyones help and thoughts will be so appreciated. Thanks so much


07-25-2009, 06:44 PM
When you move up, you want more lumens, which is more or less determined by the wattage: more watts=more light=faster algae growth=better scrubbing. The "K" number is color temperature; it should stay the same.

I don't know enough to say how much difference there is between those three bulbs, but 5000K and 5100K should be pretty close to one another and both better than the 3500K, which may encourage cyanobacteria growth instead of eukaryotic algae growth. The trouble is that color temperature only measures how the human eye sees the bulb's light. It doesn't tell you the actual spectral distribution, which determines how useful the light is to algae. The relevant figure is photosynthetically active radiation (PAR); unfortunately the manufacturers do not list PAR on the bulb packaging. There are some in-depth but possibly helpful articles here: http://www.americanaquariumproducts.com ... hting.html (http://www.americanaquariumproducts.com/Aquarium_Lighting.html) and here: http://www.aquabotanic.com/lightcompare.htm.

07-25-2009, 07:04 PM
You want 2700K. It's a greenish-yellowish. This is different from the 5100K that was first tried last year. 23W is good, 33 better, 40 better, but 50's and 60's have shown to be too much for most screens.

07-26-2009, 01:36 PM
Thanks Nathon, So Santos you telling me I should get around a 33 / 40 watt bulb and closer to 2700k rather than the 3500 i have now and the 5100 recomended before? Since I do ahve pretty much growing in there what size do you think I should go with to get it to transfer over to scrubber? I'm still lost on that part. Is the lumens that important. What should i shoot for there? Thanks ..... Ps: Anyone been to homedepot and know what bulbs they carry. Just tell me which one haha lol

07-26-2009, 01:54 PM
Santa Monica. You need to check that. 3500k should be yellow orange-ish. Nothing even remotely greenish.

ShortBusLdTang; You want the "warm" colored light not "cool" colored light. 5100k is cool-white. It is the typical cheap bulb fluorescent lighting color. That's NOT what algae likes. It's like us, wanting the warm colors.

07-26-2009, 04:42 PM
So what k bulb do i want? Do you have one for recomendation?

07-27-2009, 08:23 AM
2700, not 3500. 2700 is a greenish-yellowish, and is right between red and blue (the two primary growth colors.)

07-31-2009, 11:38 AM
Santos.... the only one i can find is a 23 equiv 120 watt r40 2700k Is this enough wattahge with me already having a problem with hair algae in my tank? Or do I wanna find some I can order online that are r40's 2700k with more wattage between 30 and 45 like you stated in previous response. The local home depot has the one but it's still only 23... but dif color.. I have a 5000k on there now and def will go with 2700k but need to know where i could find one that is more watts to speed up the growth on the scrubber... Thanks again

07-31-2009, 04:58 PM
Total wattage is more important than K. Use two 23W if you need. 3500K or 5100K will work good if you get enough watts.

07-31-2009, 07:36 PM
ok now i'm super confused.. I thought you said I wanted to shoot for 2700 k I bought a 23w r40 1200 lumens 2700k bulb......

08-01-2009, 03:12 AM
We're putting you in a sphere. Please pee only in the corner.. :mrgreen:

2300k is the best color, 3500k or 5100k will also work but not as well. They require brighter, higher wattage to give the same results.

08-01-2009, 10:40 PM
Those are good.