If you only had to choose 2... - Tropical Fish Keeping - Aquarium fish care and resources
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post #1 of 14 Old 03-16-2014, 12:00 AM Thread Starter
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If you only had to choose 2...

Time to replace bulbs. I have a 50 gallon 36 inch tank. Using an Aquatic Life T5 HO fixture that has place for 2 bulbs. The ones that came with it are marked T5 HO 6000K 39W AZ and T5 HO Roseate 39W AY. Counting wattage that's 1.5 wpg. The thing is that I see slow growth on plants but dosing with FlourinMulti and FlourinAxis have helped dramatically. I am wondering if I need to add one extra bulb. I have a standard fixture with another bulb which I could use but this presents 2 issues.

1.) It is unattractive
2.) I have to completely remove it to feed and while this isn't a huge deal it is a PITA.

Anyway, I was wondering if there were better bulbs I could use preferably using only 2. Problem is that 36 inch bulbs are only 39W. If I HAD to use all three which types and color spectrum. I have a some anacharis which is not growing to potential bit I think others are surfing a bit too.
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post #2 of 14 Old 03-18-2014, 08:24 AM
my default for bulbs is 6500K, always if i have this option
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post #3 of 14 Old 03-18-2014, 09:14 AM Thread Starter
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But with 2 6500K bulbs I am still at 1.5 WPG. Is there an alternative to the specific plant bulbs? Like maybe could I get them with more wattage at Home Depot or something at 6500K? I have been reading A LOT about lighting and it's really a ton of information to sift through. I'm planning on going to a specialized aquarium store this week to check out the bulbs but if I can get them cheaper or higher wattage that would be awesome.
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post #4 of 14 Old 03-18-2014, 09:43 AM
if you want more wattage per bulb

you can look up T5VHO bulbs
at 4' lights, a T5HO is about 54 watts, ... a T5VHO is about 97watts, your total light output per watt is down
for almost 2x the wattage, you are at 150% the light output, ... your spending more watts and not getting an equal amount of additional light

if you want other lighting options (if you have lots of extra cash to throw around)
look into induction lights

fluorescent bulbs are replaced roughly every 6mo to keep intensity up

induction lights are ... 5 years?, 10 years ?, ... a lot

induction lights are about ... almost as much light output as T5HO per watt, ... cost savings more than make up this

if you want more light, ... get more lights

you cannot mix & match light types

a T5HO is different from a T5VHO, you can't mix them

induction lights are a whole different kind of light alltogether

you want more light, (and quit using the watts per gallon rule, it's based on t12, 3500K lights)

get more lights, a basic T5 has the most light output per watt i ran across
but with fluorescent lights, replace your bulbs every 6mo to keep intensity up.

after that, T5 has more light output per area
a T5VHO has even more
and induction lights you're doing more light output than metal halide (which is pretty comparable to a T5HO)

compact fluorescent lights fold back on themselves, ... so light getting to the tank is between 25-50%, the rest is directed back towards the light, so your intensity just went down.

if you want watts per gallon, ... don't

how many lumens per square inch do you have ?
what is your lux ?

what is your water depth ?
how much light is escaping out the sides of your tank ?

do you want lights for plants ?

it won't be appealing to you, ...

so stick with 6500K, ... what lighting technology you use for that 6500K ... that's something for you to discuss between you and your bank account, do you want more lights ?,

the only way you are going to get more light in any sizable amount, ... is more lights

it's easy enough to get 7watts per gallon on any tank with a T5HO, ... it's a lid of lights, across the entire tank (standard fixture - just make sure your fixture is the size of your tank)

but are you dealing with the lights being 12" from the plants or substrate ?, 24" ???? 8" ??

you want watts per gallon, ... might be time to think smarter than listen to that rule-of-thumb anymore. it's a good place to start, ... but if you've been doing any research, you should be beyond that level of thinking.
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post #5 of 14 Old 03-18-2014, 10:11 AM Thread Starter
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I'm so confused by it all. But I have noticed some quicker growth with adding my old fixture with FloraGlo T8 30W 2800K bulb. I would just rather not have the extra fixture.

Maybe more about the setup would help.

Thank is 36" long and 20" deep with approx 3" Flourite substate. The AquaticLife dual lamp fixture approx 2.5" above tank using the feet that came with fixture. Included is a picture of the glass I have. I'm thinking that I could benefit hugely by changing it to clear glass but I can't go without because I have a cat and I like to minimize hair and other stuff getting into tank.
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Last edited by sprmankalel; 03-18-2014 at 10:31 AM.
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post #6 of 14 Old 03-18-2014, 10:55 AM
different kelvin ratings on bulbs come with different expectations

6500K is not specific to growing plants, it's the expectations that plants will benefit from it the most
it is this expectation that drives marketing to say they are grow bulbs

after 6500K for growing plants you are looking at bulbs specific to growing ... these no longer have a kelvin color rating because it no longer applies

after that, ... well that's a whole different area of study, then you get purple lights that are dim to us, and expected to be very bright to plants

i like the T5 flourescent size, ...
basic T5's are the most bang for your watt.
T5VHO (very high output) has the most output, ... and the most input, but the same size
T5HO (high output) seems to be a common standard, ... enough light output without being excessive power input.

regardless of what you do, it's size that is going to limit or dictate how much light you can put in your tank

a spiral compact fluorescent has a very small tight space
a linear bulb is thin & long
a metal halid is also compact
induction lights, ... not so compact,
LED, spread out (unless you make your own)

each of these will change what is possible.

what light intensity do you want ?

LED is almost impossible to get 7 watts per gallon (marginally more efficient than fluorescent)
fluorescent, you can get 7 watts per gallon easily enough
metal halide you could get ... 2000watts over your tank

sunlight will give you more intense light than LED or fluorescent (may change due to weather, but a sunny day you have some very intense light)
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post #7 of 14 Old 03-18-2014, 11:39 AM Thread Starter
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I ultimately want my swords to grow bigger, my anacharis and rotala to grow like weeds as I've heard and maybe eventually get some cabomba. I just am not going to get more plants if I am having trouble with the ones I have.
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post #8 of 14 Old 03-18-2014, 12:09 PM
how old are your bulbs ?
i have heard that for optimal intensity fluorescent bulbs should be replaced every 6mo.

you could push for additional lights till you start seeing deficiency problems, then scale it back a bit, ... that will be about the limits of what you can do.

higher fertilizer dosing, ... again scale it back if you see excesive algae

add CO2, watch for fish breathing to know your limits & scale it back then.


as one increases, so too will the ability of the plants to handle more of the others, ... there will be a limit where more light/fertilizer/CO2 will make no improvements, and even more will start to have negative effects.

but if you want more light, ... you're going to have to get some serious lighting upgrade, ... either many more lights, or different types of light entirely (different light technologies).

Last edited by Flear; 03-18-2014 at 12:17 PM.
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post #9 of 14 Old 03-18-2014, 12:20 PM Thread Starter
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The bulbs do need to be replaced. They are more than 6 months old. I'm not sure it they're a year old yet but replacement is coming very soon. Hence all the questions. Would it be beneficial to get 2 of the same bulb? It didn't make sense to me to have the 2 different but that's what the thing came with. I can't even find how much is the max wattage bulb I can put in. I do know that if the fixture only puts out 40 watts a 100 watt bulb will only be 40 watt output. So I don't want to get higher watt bulbs if it will only accept the 39 watt bulbs max. I know you said that this is an old rule of thumb but I am seeing some benefits to adding the extra fixture with the extra 30 watts. Maybe it's the specific bulb. Again, the reason for all the questions. I am totally ok with throwing out the WPG rule if I have light that is actually gonna be used rather than wasted. It doesn't make sense to put a higher wattage bulb if it's not the right kind to properly support photosynthesis.
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post #10 of 14 Old 03-18-2014, 12:49 PM
i dono about mixing bulbs like that.

Very High Output bulbs have different ends to prevent them from being mixed up

reg & HO bulbs i'm not so sure about.

if you can identify the kinds of bulbs in your fixture now (HO or not) and stick with that.

otherwise if you want more light your after either a new fixture or trying to make one yourself

but if you put together one yourself you could put as many lights in it as you wish, ... the things i dream & fantasize about :), but don't trust my ability to put together a decent reflector for it.
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