plant lighting and setup questions

[evercl92]

Simply put, your current lighting setup isn't going to get much to grow - other than anubias and java fern.

Your tank is too deep for the crappy T12 lighting that you currently have. If you want different plants to grow, then you need CF, T5, or T5 HO lighting.

The 50/50 bulb is a waste of your electricity, as far as plants are concerned. They can't use half of the output of the bulb.

Just because you have a higher WPG for half of your tank, doesn't mean that it's sufficient to grow plants. All of the bulbs put together aren't gonna penetrate the water's depth any better than a single one of them. WPG isn't really that great of a 'rule' anyway. Lumen output is far more important.

And again, your current lighting setup isn't going to get much to grow.

 

[edtriou]

First question: lighting. All I have right now are 2 standard light fixtures w/ 36-inch bulbs and one w/ 2 x 18-inch bulbs, which would be about 90W total. Is this enough to grow certain plants or should I just put some of the money towards all new bulbs towards a good lighting fixture?

WyldFya has a great post, hopefully this helps. For me, that took out all the guess work and made it a simple math problem.
http://www.monsterfishkeepers.com/forums/showthread.php?t=73446

I ran some math for your equation, with some missing assumptions:

• 125g tank = 72Lx18Wx23H.
• 36" bulb = 30W T12 2250 Lumens
• 18" bulb = 15W T12 800 Lumens

Current Lumens:

• = (2)2250 + (2)800 = 6,100

Here's your current LPG factor, using the site above:

• = 6,100 / ((H*2)+W+L)
• = 6,100 / ((23*2)+18+72)
• = 44

If I consider only 1/2 your tank, these would be the numbers. Note: I didn't take your 1/3 suggestion, since most of your bulbs are 36", ie: lumens is distributed across that length.

• = 6,100 / ((23*2)+18+72/2)
• 61

From the site, 44 or even 61 is really, really low:

• 50-150 is low to moderate lighting - (Fish only or lower-light plants)
• 150-250 is moderate to high lighting - (typical planted tanks without CO2)
• 250-350 is high to very high lighting - (Good reef tanks or heavily planted)

To calculate what you would actually need, do the reverse. I assumed you would probably want around 150 factor, so here's that math. First one is for 1/2 the tank, the other is entire tank:

• = 150 * (H*2)+W+L
• = 150 * (23*2)+18+72/2 = 15,000

• = 150 * (23*2)+18+72 = 20,400

You can now see how far off your 6,100 number is, about 1/3 of the light that you actually need for typical (non-high light) plants without CO2.

Hope this helped. I sure helped me when I could see it quantitatively, instead of looking at bulbs and wattage, and wondering why stuff was dyeing.

Ed

 

[pwmin]

Thanks for all the replies. Math definitely helps out my situation. I'm sorry, my reading comprehension was never my forte and I didnt have time yet to thoroughly scruntinize all of the stickies. I've moved on from even thinking about trying to get the lighting that I have to work. So far, I've been looking into T5 HO lighting. Petsmart actually has some fixtures (Hagen Glo) but they don't come with bulbs and they dont even have the right ones

Read the highlighted sections much closer.

i get that, thank you. youre still not answering my basic question, though of only having plants in 1/3 to 1/2 of the tank (I DO NOT want light and plants throughout the entire tank). If I know the answer to that, I will be able to figure out how much lighting to get and the lengths. You can bash my head in if you want

Right now I have a 6' tank, so I think I would go with 36" lights, which would be perfect for 1/3 when I upgrade to an 8' tank. If I go with a 10' tank later on, I would probably sell my 36" stuff and get 48" lights. I will do some figuring and come back with any more questions.

 

[pwmin]

So, here's what I'm thinking (I am assuming I only need to light the area where the plants will be and if they grow outwards, they may die due to not receiving enough light):

In planning for my future tank, which may be up to 120"x48x36 (LWH), if I go with 10 x 36" T5 HO bulbs, that will put me at about 35000 lumens (10 x 3500). 36 inches of light would give me .3 of the tank, which will be plenty of area for plants. So, going by the equation of lumens/[(H*2)+W+(L*.3)], that will give me a factor of 210, which I'm thinking should be good enough for what I want. If I go with 12 bulbs, i should have a factor of 270.

Now, If I go with 4 36" bulbs for my current tank, I should end up with a factor of 140. To supplement this to get to 150-plus, I could use either of my other light fixtures as an add-on. OR, 6 x 36" bulbs should give me a factor of 224. Here's my math (as figured earlier by edtriou):
Factor = Lumens/[(23x2)+18+(72/2)] - obviously 72/2 = 36" of bulb

So, I found these T5 HO fixtures: http://www.northcoastmarines.com/lighting_systems_fluor.htm
Judging by what I've figured (if it's correct and if the fixtures in the link will work out okay), do you think I would be okay just buying the 4-light fixture for now and then buy a 6 to add on later or should I just wait and save up a little so I can get a 6-light fixture now and another one later? I guess one way to look at it is do you think 150 now and 210 will give me decent results (they don't have to be near as nice as some of yours) or will I be much happier with 224 now and 270 later (I'm sure 270 will be more than I need, but maybe not)?

Sorry for the super-long posts.

 

[WyldFya]

HO T5 by hagen are very good for planted tanks. However, your math is wrong. 10 36" 38W T5 bulbs at ~250 lumens per watt put you well over 90,000 lumens. Unfortunately you are still only looking at a third of the equation. I asked you to read the parts in bold once, wrote the initial questions once, and now ask again.

You need to list the specific types, sizes, wattages, lumen or lux (if you know how to find this), color temp, and number of lights.

There is more than just lumens put out that needs to be taken into consideration.

 

[pwmin]

What am I missing? According to all the T5 HO bulbs I looked at, 39W bulbs put out 3500 lumens. I never saw anything about 250 per Watt.

How can I tell you all of those things when that is what I'm trying to find (i'm trying to find out what I should use)? I'll see what I can come up with from the lights i listed, though.

type: T5 HO
size: 36"
wattage: 39W each
lumen: 3500 each (from what i heard. According to you, its like 9000)
color temp: i guess 6700K, but if theres something better, i need to know that
number of lights: depends on how much light i need

 

[WyldFya]

What I asked, and apparently you have missed 4 times now, is what you HAVE.

 

[pwmin]

What I asked, and apparently you have missed 4 times now, is what you HAVE.

I thought we already moved on from there since it was already determined they wouldnt be adequate? Right now, I have T12 (i think thats what it is, you know, the standard pos stuff that comes with all-glass aquarium kits). 2 x 36" strips (25W bulbs right now) and a strip w/ 2 x 18" lights (15W each). They are supposedly "Full-spectrum" from what I can gather. IDK what color-temp that is exactly and have no idea on the lumens. I don't see how it matters what bulbs I have right now as I was looking to replace them. I now know that the fixtures I have won't work in any stretch, so I've moved on to T5 HO. I thought I already answered those questions to the best of my knowledge and it seemed to me like other people were understanding what I had...sorry.

 

[deR]

Well I have not read all the thread, but so far im agreeing with Wyldfya. Your bulbs don't penetrate deep enough to reach the plants in the bottom of your tank, you should consider some Power Compact lights with 2 actinic bulbs and 2 6700k daylights, for that size a tank and with your plan i would go with a 48" strip, which will put out for most common PC's 260watts. You can and I would recommend you do this, get a 60" strip or a 6ft strip.

 

[evercl92]

2 actinic bulbs and 2 6700k daylights,

Not sure why to waste the money on actinic bulbs

Or CF lighting at all, for that matter.