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Re: Best fluorescent tubes? (2x20 watt PlenPlax)

Jason wants to know if 2 20watts flourescents is enough for
his 55 gallon tank

Algae are plants, so it's not too hard to grow algae when
you're trying to grow other plants.  But you can grow other
plants without getting too much algae, without getting more
algae than you cn deal with by regular maintenance.  You
want as much light as (the desired) plants can use.  So how
much is that?  Depends on how you set up the tank, what
plants you use, how many fish and how much fish food you
put in the tank.  But don't get lost in all the parameters.
 As a rule of thumb, aim for about 2 watts per gallon for a
tank without added CO2 and more, up to roughly 4 watts per
gallon for a tank with added CO2.  So for a 55 gallon tank,
I'd use more light to grow plants.  I'd gut the hoods and
install a 55 watt Power Compact (ala AHSupply.com) if I
wasn't going to inject CO2.  If I was going to add CO2, I'd
might double that to 4 bulbs at 55 watts -- I think those
will fit on a 55 gallon, but you'd need different hoods.

Most plants aren't going to be able to make much use of
light for more than 10 ro 12 hours or so each day -- you
can't expect them to work all day like chickens on an egg
ranch that are forced into long days with artificial
lighting. So the extra hours are pretty much just there for
the benefit algae.  Along with adding more light, I'd trim
back the lighting period to about 10 hours.  Be careful not
to overstock and overfeed -- without a lot of light, the
plants can't make use of a lot of nutrients -- the excess
nutrients that the plants can't use, the algae will.

Can you grow plants with just the 2 20watt bulbs on a 55
gallon tank?  Sure, but it will be harder in some ways --
you will be limited in your selection of plants (try
anubias for low light tank); they will grow very slowly
(which isn't a bad thing if that's what you want); leaves
might "collect" algae faster than new leaves grow (so you
won't be able to use pruning as a way to keep of algae
growth).  On the other hand, a slow grow tank, because
growth is so slow can be a very low maintenance tank.  You
might find that many plants look good at first (while they
live off of the reserves they built up while growing at the
nursery) but then slowly seem to just poop out and die.

But in any event, it's a question of balance between
nutrients and light.  Nutrients are Nitrogen, phosphorus,
potassium, and trace elements).  Nutrients come mostly from
fish food but also from fertilizers (if the fish food isn't
enough).  Light gives the plants the energy to make use of
the food.  On a low light tank, try adding Tropica Master
Grow of SeaChem Flourish at the recommended levels along
with a little potassium.  This will provide the trace
elements plants need and ensure that there isn't too little
potassium.  Adding potassium won't encourage algae growth. 
Nitrogen and Phosphate will come form the fish food in a
low light tank -- almost certainly the nitrogen will and
probably enough phosphate.  You can get potassium from
SeaChem also.

One of the most important things about having plants and
not a lot of algae is to clean away algae regularly -- stay
ahead of it, stay on top of it.  If you let it get ahead of
you, it can be a bear to get things back in control again
-- and that's more work than staying on tops of things.

BTW, generally speaking, the color (brand) of fluorescent
bulb isn't as important as the the amount of light.

Hope that helps,
Scott H.

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