# What's the difference between these two bulbs?



## Jeane09 (Nov 19, 2013)

Hi, I have a newly planted tank (20 gal L). Some algae suddenly so I think the lights are on too much. I had the light on 14 hr a day but have cut it down to 10, am thinking to reduce to 8? The plants are: water sprite, two kinds of anubias, java fern, amazon sword, rotalia indicia and some kind of vallisneria. 

The hood came with a full spectrum 13 watt T8 bulb but I replaced it with a 20 watt T12 bulb (600 lumens) that was labeled spectrum for aquarium plants, thinking they'd need better light. Not sure now if that was necessary. Is there much difference between these two bulbs? what does the T8 and T12 mean?

Does it matter much if I use the new light at 8 hours, or put the original bulb back in, for 10-12 hours per day? I'd rather have the light on for longer viewing hrs per day. How do I tell if the plants have enough light? They seem to be growing ok right now- most have new leaves. I know what light deprivation looks like in houseplants- they get leggy and/or pale- do aquatic plants show the same symptoms?

Thanks for any input.


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## BettaGuy (May 6, 2012)

I have my lights on 9h a day and the plants are growing fantabulous with minimal algae growth (of course I'm also fertilizing, with liquid carbon and fertilizer). But as to what those numbers and letters in the description of your bulb mean, I have no clue. I have heard though that T12 is better than T8 for growing plants.


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## Jeane09 (Nov 19, 2013)

Ok. I am giving them some liquid plant food, too- once a week.

Another question I just thought of- if the plants use up oxygen at night, is it beneficial to have the aerator on at night and not during the day? Just wondering.


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## BettaGuy (May 6, 2012)

yes it is, especially if you have no water surface movement which naturally gets oxygen in the water. If thee is surface movement an aerator is unnecessary.


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## Jeane09 (Nov 19, 2013)

There is surface motion but not much- the flow from power filter breaks it some but it is pretty gentle (I think- not much experience to judge by yet).


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## BettaGuy (May 6, 2012)

If the sound doesn't annoy you (in a bedroom it would) and you don't mind spending the few dollars. I would get an airpump with an airstone for the night.


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## Jeane09 (Nov 19, 2013)

Yes; I've already got one. I had it running constantly but then thought maybe it would be better just at night. It's not too noisy- located in living room- and I put a folded rag under the pump to lessen the vibration noise.


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## lohachata (Jan 27, 2006)

aT8 bulb is thinner than a T12.....and although it uses less power than a T12 , it actually puts out more light..
i never shut off the air going into my tanks..on some i have 2 or 3 large sponge filters along with a 4 inch airstone.....the stone stays on all the time whether there are plants in the tank or not....


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## BettaGuy (May 6, 2012)

Loha, i just figured for the day you would want as little disturbance of the surface as possible to keep any Co2 in the water?


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## Jeane09 (Nov 19, 2013)

I did notice the one bulb was thinner- so it is more energy efficient? I wasn't sure if there were any other differences.


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## BettaGuy (May 6, 2012)

ok, so what i said in the beginning was wrong, my bad. T12 are the old bulbs, they don't even get created any more. They use more energy than the T8 which are more modern. But to which one is better for your plants, no clue. Your gonna have to read up on the specs of each bulb and do a bunch of research, but I would go with the newer one, which is the thinner one, the T8. Sorry for what I said regarding the bulb before. 

But it all depends. Depending on how deep your tank is, and what the output of each light is. The light specs should all be written on the box for your lights.


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## lohachata (Jan 27, 2006)

almost all of my lights are 48" shop lights using T8 daylight bulbs..they are rated at about 6500K........which is what plants like..
for deeper tanks i like the T5 daylight 6500K fixture...the light penetrates deeper tanks..
here is a pic of some aponogetons that are about 3 or so weeks old from a bare bulb..
the light is from a shop light with daylight bulbs...


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## Jeane09 (Nov 19, 2013)

BettaGuy- how can they not be created anymore, if I bought one new in the store surely someone is manufacturing them?

Lohachata- do you use that tank just to propagate plants? It's pretty w/all the green.


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## lohachata (Jan 27, 2006)

they still make the T12 bulbs , but the T8 bulbs are better..they consume less energy and produce more lumens of light..many folks get a little crazy with technology and go on and on about all of the more scientific stuff , but i like to keep things simple as i am just not that smart...nor do i have the time or money for it..
T5 bulbs are even better yet but are a little more expensive..but i do love the ones i have..great for deeper tanks with lots of plants...
that little tank no longer looks like that...it is now set up with a couple of discus and some blue rams.it is planted with some corkscrew vals and crinium calimastratum...


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