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Discussion Starter · #1 ·
And please, I swear I used the search engine before asking. If there's already a thread about this (and I'm sure there is) please point me in that direction. Thx.

So my question....I have a 6g tank that is very short. After my substrate (SMS), I'll have 5-6" of height. The light is 15w flour, 67k. Given the height, is it still considered low light?
 

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Discussion Starter · #3 ·
I guess that would be one part of the huge thread algae I constantly dealt with? No ferts, high light, no co2. Do you think?
 

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that's low light.

there is a minimum light threshold for plants to thrive. you can't put a 2.5watt bulb on a 1g tank and expect to have medium light, because its 2.5wpg. the bulb simply doesn't put out enough lumens or energy for the plants to thrive, regardless of how small the tank is.

15w. will give you low light. i have a 15w strip on my 10g and it is algae free with no ferts and no CO2, but the plants hardly grow at all. on such a short tank though, 15w may give you a bit better growth than it does on my 10g. once you get to 10g or smaller, the "wpg" rule no longer applies. i have 40 watts over my 5.5g, and takashi amano recomends 50w on a 5.5g.
 

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Discussion Starter · #5 ·
Ahh, now I'm even more confused! But thanks, Lucky! I guess I have more reading to do. :icon_frow
 

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I think amano tanks are an exception, just about every tank I have seen of his is using at least 5wpg and some even more than that regardless of size!

Also you will notice that his fixtures are mounted high off of the water surface too.

I also think that the shorter height in the tank makes a big difference too 3wpg in a 20" tall tank isn't gonna be as efficient as 3wpg in a 5" tall tank.
 

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regardless, you need a minimum ammount of energy output for the plants to thrive. the plants absorb the light energy and use it with carbon, nitrogen, and micronutrients to grow. they need that minimum light output. like i said, a 2.5w bulb on a 1g tank is not sufficient, even though you have 2.5wpg, because a 2.5w bulb just doesn't have enough energy output or lumens for plants.
 

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regardless, you need a minimum ammount of energy output for the plants to thrive. the plants absorb the light energy and use it with carbon, nitrogen, and micronutrients to grow. they need that minimum light output. like i said, a 2.5w bulb on a 1g tank is not sufficient, even though you have 2.5wpg, because a 2.5w bulb just doesn't have enough energy output or lumens for plants.
We are not talking about a 1g tank or 2.5w bulb.
 

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Discussion Starter · #13 ·
LOL! No, not a caveman...but my house faces E/W and doesn't get a lot of light.

Oh, and yes, eklikewhoa is correct. This isn't a 2.5 watt bulb, it's a 15 w flouro tube.
 

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Back on subject, I'd call that low-med light. Algae is so normal in non-co2 tanks. Do you perform water changes? If so, do you allow the new water to site for a while? Also, what kind of surface turbulence is there? I'm trying to get at why you've got algae....
 

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Discussion Starter · #15 ·
Ernie...actually, it's not running at the moment...just filled with substrate. However, I've torn this tank down several times because I constantly had algae problems, mostly bba and thread. I thought it was also med light, which is why I wasn't doing co2 other than Excel. I had some fast growers as well as crypts and mosses. I also had najas floating that would literally be covered with this brown nasty mush type of stuff within a day or two after removing it. I know that I didn't have enough nitrates. It was stocked with three dwarf puffers only. I changed 50% of the water weekly trying to keep up with the algae and get it out of the tank the best I could. I also used fert tabs under the stems and crypts. I'd also add some mulm from the bristle nose tank, but I still rarely had a readable nitrate level, so I'm going to get some flourish nitrogen in case I run into that problem again. Do you think with this light level I should use co2 AND excel, or is that overkill for a med lighted tank?

*edit*

I just saw Booger's post and what he has on his plants is the exact stuff that would cover my najas:

I need a quick confirmation on what type of algae(s) I'm looking at here. Aside from small shrimp, what will eat it? I think otos are next up to bat.

 

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Hmm sounds like the majority of algae was growing near the top fo the aquarium. I'd suggest
1)moving the light up a bit.
2)Making sure there is surface disturbance. I really think this helps cut down on non-co2 tank algae.

Also, is it 15w compact fluoro or just NO fluoro?
 

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Back on subject, I'd call that low-med light. Algae is so normal in non-co2 tanks. Do you perform water changes? If so, do you allow the new water to site for a while? Also, what kind of surface turbulence is there? I'm trying to get at why you've got algae....
I'm wondering what the correlation between aging the water and algae would be?

As far as tank depth goes, everything I've read besides conjecture on internet forums regarding the depth of the tank suggests that the effect only comes into play when talking about really deep tanks.
 

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Discussion Starter · #19 ·
Hmm...not sure about that aman74. But Ernie, yes the bulb is a NO flour tube. Unfortunately, the algae didn't seem to prefer the top or bottom. It was an equal opportunity annoyance.
 

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Hey sorry for a late response. I'll try to explain myself:

1. The idea is that a planted tank need stability. If you have abrubtly rising or falling co2 levels, or any other nutrient for that matter, it's much easier for the algae to outcompete the plant for that nutrient.

2. Typically water from the tap is saturated with gases, including co2.

3. The problem with using water without aging it to allow the gasses to escape is that you are making a huge spike in co2 in the tank. This may seem like a good thing, but in reality it's just an imbalance. It's hard for the plants to use this up quickly, so the algae does.

There are other threads here that address this issue, I think it was populated by Mr. Tom Barr.
 
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