Do Light Bulbs Affect Wpg?

[Jen]

Silly question about bulbs. If I'm running 2 54 watt lights on my tank, does the type of bulb make a difference? My lights are HO T5. Technically I have 2 wpg on my tank, but someone was telling me it's more because they are high output bulbs.

Thanks

 

[KittyKat]

Wpg is watts per US gallon so it doesn't matter which lights you have, your wpg is the same.

On the other hand, the light produced by x wpg T12 is less than the light produced by the same x wpg of T5s, which is in turn less light than would be produced by x wpg HOT5s. So with your 2 wpg HOT5s, you get more light than you would with 2 wpg T12s.

The guidelines for wpg were originally for T12s, if I remember correctly, so to get equivalent lighting, you would need to use a lower wpg with T2s.

 

[BigTom]

Watts per gallon is pretty much meaningless for anything other than the broadest of guides, sounds like you have enough light to grow almost anything, assuming your dosing, co2 and flow are all up to scratch.

 

[Jen]

I am not adding pressurized co2, I am dosing carbon at this time. I was trying to stay away from a really high tech setup when I started (which meant the purchase of a 110 watt light fixture was a silly move). May I ask what flow has to do with it? It's been a while since I've done a full on planted tank, and that wasnt something we really dealt with then.

 

[BigTom]

Quite a long thread over on UKAPS about it, with great input from people who know far more about it than I!

http/ukaps.org/forum/viewtopic.php?f=38&t=1167

 

[RadaR]

I am not adding pressurized co2, I am dosing carbon at this time. I was trying to stay away from a really high tech setup when I started (which meant the purchase of a 110 watt light fixture was a silly move). May I ask what flow has to do with it? It's been a while since I've done a full on planted tank, and that wasnt something we really dealt with then.

Flow and circulation is something that we regard as very important now. For example, what's the point in injecting lots of CO2 if it's not circulating around the whole tank and thus not getting to all the plants. The same goes for nutrients. It would be as if we weren't dosing enough.
Deadspots are also eliminated. Algae can thrive in stagnent pockets.
The chance of debris/detritus getting sucked up by the filter greatly increases if the tank has good flow and circulation. Thus, less is left to fall to the bottom of the tank where it would otherwise breakdown and leach ammonia which would trigger algae spores to bloom.

 

[Jen]

That is quite the thread Tom, I got through a few pages, I will go back and read all of it.

That seems to make a lot of sense RadaR. I have a spray bar that I cut a little shorter to fit the width of my tank, and flows down the length towards the intake, so missing a few holes has strengthened the flow. I have a power head at the opposite end helping to keep the top always moving, but maybe I should put it lower down to move the mid level of water around. hmm. more research!