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I'm putting together a new 29g that will be heavily planted. What is a good 30" lighting fixture for this size tank? I'd like to get 2.5-3wpg for medium light plants.

renoharps,

Hi there. I did some research for my tank and found so far that I could
either get a single 55W Power Compacts unit or a double with 110W.
Unfortunately, this would bring your WPG to either to 1.9 or 3.8,
respectively. You are looking for something in the middle of these.

Well, I would try to find out what actually constitutes the WPG equations
parts. Sure, there is the wattage of the light, but what about the gallons?
Are they based on the volume an empty aquarium can hold or the actual
water content in the aquarium?

My AGA 29G holds if really full close to 25 gallons of water
(because of gravel and bogwood). This would mean that 55W
actually turn out to be 2.2WPG and as such almost what you are looking for.

I would be interested what the rest of the community has to say to this.

Hope this helps,

Ingo

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Proud Member of the New Jersey Aquatic Gardeners Club

if 30"(75cm) is the length of the tank by all means use that lighting

I think a normal fluorescent fixture at 30" long gives you 24" bulbs that are 20watts each. You can't really accomplish over 2wpg without covering the whole top of the aquarium in these bulbs but that would be the cheap way. The other option is compact flourescent. A 30" fixture holds 55w-65w bulbs. 2 55w would give you 3.8wpg. More than you wanted but it's the simplest option. A 20" fixture could hold 2 36w which would give you 2.5wpg but the light would be more concentrated in the center and the ends might seem dark. Or you can use 2 strips. 1 with a 65w cf and 1 reg fluoro with a 20w giving you 3wpg. Right on the light you want, slightly less expensive than a 2 bulb cf strip, slightly less space than cramming 4 reg fluoro bulbs on there, but you have to fit and deal with 2 lighting strips.

How's the quality of the Coralife brand strip lights? I was thinking of this one. I think it's the best I can do to get me close to my desired wpg.

http://www.bigalsonline.com/catalog/product.xml?product_id=31566;category_id=1875;pcid1=1843;pcid2=


Last edited by renoharps at 22-May-2005 20:20

Last edited by bensaf at 22-May-2005 20:37

renoharps,

The fixture would be perfect. Nice bulb too.

It will give you a tad over 2 wpg. This will allow you to grow a very wide range of plants. Any more light then that and you would be in the range where you would need to consider Co2 supplementation to avoid algae issues.

To the poster that asked the question about wpg and water volume - the wpg thing is more of a guide, nothing hard and fixed. There are variations depending on tank size and height. Bascially it's considered to be applicable to tank size rather then the actual amount of water. It's assumed more watts = more intensity, more gals = larger tank.

---

Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.

Thanks for the info everyone!

Bensaf, how did you change the URL I entered into an active link? I couldn't figure out how to do that when I created the post.

reno,

Simple.

On the page where you type your reply/new post, scroll down and there's instructions on how to do all sorts of things

Press the "Easy Markup" button key in the page address or copy/paste the adress. Click ok and you have something like this:
http://www.fishprofiles.com

Last edited by bensaf at 23-May-2005 08:27

---

Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.

Little_Fish,

Here is a more detailed description of wpg as well as a way to calculate it: http://www.fishprofiles.net/faq/plant-lighting.asp

just_one_more,

Thanks for this link. I remember having been on that page before, but I
was in a rush and didn’t take the time to study it in detail. Well, this morning
I did and I dug out my Excel spreadsheet and did the calculations of a few tanks.

Here are my results:

First of all, all tanks inspected concluded in the same WPG results +/- 0.1

I looked at the AGA 29G, 55G, 125G, and 180G. In each case I assume a gravel
height of 3 in and a distance from the light source to the tank of 3 in as well (that
makes it easier for a lazy guy like me , the distance from the light source to the top
of the gravel in the equation is then simply the height of the tank).

The results (in WPG):

Low light plants 1.65
Low to Moderate light plants 2.47
Moderate to Bright light plants 3.71
Bright light plants 5.56

In addition, I found that the larger the tank, the higher the WPG for equal
conditions has to be, but only by a max of 0.18 and as such could be
neglected (i.e. Bright light plants 29G is 5.48 and 180G is 5.66).


I post this here in case anyone cares

Ingo

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Proud Member of the New Jersey Aquatic Gardeners Club

I have some questions along the same line as this thread. My 30 gal planted tank has a 6700K fluorescent rated at 20w. (only 20" long which only lights the middle of tank)

To upgrade this light, I have a choice of either a 36" fixture at 39w which would cover the entire tank end-to-end, or that 55w Power Compact mentioned above.

Wouldn't it be better to cover the entire tank end-to-end even if the wattage is lower?

Also, would a sudden sharp increasein light levels cause an algae bloom or stress the fish?

Thanks for your input!


All best,
Joe

Wouldn't it be better to cover the entire tank end-to-end even if the wattage is lower?

Depends.The ideal would be to have good light evenly spread. What your basically asking is , is it better to have poor light evenly spread or good light in a limited portion. My own preference would be the additional wattage even if not the entire lenght. It's easy enough to work with. The high light plants can go in the middle with the outer areas filled with lower light plants like crypts and anubias. The other option leaves you with just the ability for low light plants only thereby reducing your options.
You have to make these kind of adjustments anyway. Even in the bright tank tall plants will shade smaller ones etc so you have to plant accordingly and choose plants that can handle the shading.

Also, would a sudden sharp increase in light levels cause an algae bloom or stress the fish?

.
Again depends. For fish the light shouldn't cause any problems. There are some species that don't like it too bright, but they can be catered for by having floating plants or thick tall plants to provide cover,shade and security.
As regards algae, the problem won't come from a sudden change as much as from having too much light over too few plants consistently or for too long a photo period. Too much light with too few plants to use it will cause algae problems. The tank should be planted both quantity and species wise in a way that the available light is best used. Common sense really, paying alot of dollars for a light system to light a solitary crypt is not much of an investment

---

Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.

OK, thank you, bensaf!

I should have made it more clear that my tank is already well established with low light plants, and that it is fully stocked with Gouramis, Neonas, and Corys.

As you might well expect, these plants are not growing or thriving well at ~0.6 watts/gallon. I am concerned about suddenly increasing this level to ~2.0 watts/gallon if I get that power compact light!

I was thinking that going from a 20w bulb to a 39w bulb may be easier on the tank inhabitants, but I agree with you that the PC is a better choice in the long run.

You got me set on the right path! When I get that light,I will also purchase some more plants and just let them float for awhile until the system adjusts to the higher light level. Good thinking!


Thanks for your input!


All best,
Joe

Success!

I bought and installed a glass top and a 2 x 30w striplight for my 30 gal long just yesterday! The difference is astounding! I can't say enough about it!

I just can't believe how much better my tank looks. I have been raving about it now for the past 24 hours. Most importantly, there has been absolutely no differencein the behaviour of my fish! I was afraid that a sudden increase in light would stress them . . . maybe I just worry too much . . .

This wasn't as cheap as the 65w power compact mentioned above, but I'm extremely happy with my purchase. The fixture is from Marineland, the same maker as my tank, so the "Oak" stand, tank, and light matches perfectly. Also, I have the flexibility of using different tubes in this fixture.

Now I can't wait to see how my plants grow!!

All best,
Joe