55 Gallon Lighting

[rschall]

My apologies if this is a repeat (and I'm sure it is).

I have a 55 gallon fresh water tank. I've had it for over a year and it has several types of neons, gouramis, etc.

My problems have been with live plants. Until recently, I was always under the impression that as long as you bought those 20k bulbs (full spectrum, blah blah), then you'd be okay. However I noticed after a few weeks that I wasn't able to keep any type of plant alive for long. They'll grow a bit, but not like they should. I asked the guys as the local aquarium store (probably not the sharpest guys) and they told me to get this dual florescent reflective light (48inch). He said "Dont worry, that's more than enough light to grow all sorts of swords, etc". Well, needless to say, he was way wrong. I believe they're only 30-35 watt bulbs in there. And from everything I'm reading up on, you need at least 2 watts per gallon. So I know I'm way short.

Long story short, here's my question....

There's a lot of talk about T-size this, and watts that and spectrum this.... I'm trying to keep the costs down, since its a simple tank and I'd just like to have some simple plants stay alive in my tank. Should my current hood that I just dropped $130 for be enough to handle the types of bulbs I need? And what types of bulbs should I get? When I look at petsmart or even online, I can really only find up to 45watt bulbs for 48in length. That certainly won't be enough for what I was reading I'd need.

Any insight would be much appreciated for this frustrated newbie enthusiast.

Thanks in advance.

 

[anodized]

the wattage of light needs to be higher the deeper your water is. 45W probably wouldn't be enough to grow much, if you had 2 of those .. you'd have a nice low light setup probably.

6700k is the correct "plant light", although others might work just not as well - you might get more algae with a higher colour temp

also if the plants are not growing make sure you have enough nutrients in your water, N and P can be measured with your standard test kit.

the maximum amount of light you can put in your hood will depend on the ballasts for the light fixture you have, the stronger the ballast the stronger bulb you can use. if its not enough for what you need, you may have to add another. personally i use compact flourescents because they pack a lot of light in a small space. but guys have been getting along fine with T5 and T8 bulbs as well

 

[SuperColey1]

2WPG to grow plants is a myth.

The WPG rule was based on T12 light (12 eights of an inch - so 1½ diameter tubes) and therefore there is a restrike issue (I will explain below)

With todays modern lights most people are using T8 or better and therefore ther is less of a restrike issue.

Restrike is that when you use proper polished metal reflectors (which are a must with planted tanks) then the light that is not going to the tank hits the reflector to be redirected towards the tank. Unfortunately some will be blocked on its return by the bulb (restrike).

This means that the thinner the bulb the less restrike there is and the more light is redirected back to the tank.

So If you have 2WPG with a T12 then although you still have 2WPG with a T5 (5/8ths of an inch diameter) because after 1W of T12 = 1W T5 in reality by this basic measure rule there is moreof that 1W going into the tank with the T5.

All very complicated but basically the lights that are best in order are: HO T5, PC, T5, T6, T8, T10 & T12.

The lower the number the lower WPG you need for the same amount of light being directed towards your plants.

All that being said 2WPG of T8 will grow almost anything unless your tank is 3-4ft deep. 1WPG will grow lots and lots of plants. There are many people downgrading their lighting these days after years of people pushing for 4WPG they are now going back down to the 2WPG mark and some people lower still (I am now down to 1.5WPG and my plants grow beautifully.

I would check in the planted section and look through a few journals to see what light people are using and what they can grow with that light. One of the Mods in there LLJ is from America so will know more about what lights are availabe to you and she is also an expert at low light, non CO2 tanks so she would be your best bet.

Andy