Marc M

I am considering adding some common plants to my 75G freshwater community tank but am having a hard time finding info about my particular light fixture. I have a 48" Perfecto fixture that sits atop a glass top. It is the type with the reflectors in it. It hold only one flourescent bulb. Everything I read says to shoot for 4 watts per gallon as a minimum. What type of a bulb would I need? How much does the reflectors amplify the bulb's wattage?"

Butterfly

If you want high lights then you will need the four watts but low light-med light plants don't require that many watts.
Check out these listings for plants. Match what you have and have fun planting your tank
http://www.plantgeek.net/plantguide.php
carol

Nutter

4wpg is very high light & honestly I am yet to find a plant that can't be grown under 3wpg in any tank under 2ft deep. Though I'm sure some will argue that but I just speak from my personal experience & the experience of others I know that are right into thier planted tanks.

Look for tubes with a light spectrum emited panel on the packaging. Look for large spikes in the red & blue areas of the spectrum. These tubes will give superior plant growth to tubes with large spikes in the green area of the spectrum. You will be best served by having a combination of tubes, a couple for plant growth & another 1-2 standard cool white tubes to keep the aquarium pleasant to look at & to show up your fishes colors nicely. Many people find it easier to work of the Kelvin, (K), rating of tubes. If you prefer to do it this way then look for tubes between 5-10,000K. Many people use tubes rated at 6,700K & are very happy with them. I prefer to use a combination of tubes to give the plant growth & visual effect that I like. I use 2 x 6,700, 1 x 10,000 & 1 x Tri-phosphur tubes. I don't know the Kelvin rating of the Tri-phosphur tube but it is a standard tube available at most hardware stores.

As for reflectors there are a few options. Polished metal isn't a very good reflector at all & reflects less than 50% of light while also producing a spotlight effect, just like shining a light at a mirror & seeing the beam bounce of it. The two most effective reflectors are plain old flat white paint, which reflects 75% of light or mylar film, which reflects 98% of light & doesn't give the spotlight effect. These results will vary a bit depending on the shape of the reflector but the rules still apply. Mylar the best Flat White Paint second best & everything else isn't very good. I use flat white paint on all my reflectors & the increase in light is quite noticeable from the polished metal that most fittings come with. You can't go far wrong with it either. You get 4lts Flat white paint for $15 & will probably have enough to paint to coat every reflector you will ever own. Make sure you use a few coats to give a good even finish.

Marc M

Thanks a lot Nutter. That is a lot of great info. So for a 75 gallon tank I would need about 225W of light? Just browsing the pet store the highest bulb I saw was 65W. Does the 225W take into consideration the light being reflected into the tank from the reflector material? Otherwise it seems I would need to invest in a new fixture that can support multiple bulbs.

Nutter

I don't believe the WPG rule takes reflected light into account as there can be too much variation in how much light is reflected.

What are the dimensions of your tank? I hate this tank size in gallons stuff as it doesn't really tell you what a person has. Also what kind of fittings do you have, are they T8, T5 or T5HO? What length are the fittings? Is it a store bought hood or glass lids or DIY hood?

Sorry about the questions but if you can answer those things for me then I can get an idea of what will work well for you.

Marc M

No problem at all. It is a standard 75 Gallon which is 48 long, 18 deep, and 18 tall. The bulb in use is a 30W T8. The fixture is a store bought single tube light.

Marc M

Sorry. It is a typical two piece glass top wit hjust the light sitting atop.

Nutter

One of my planted tanks is exactly the same size so this will be fairly easy. Go for 4ft long 40w fixtures as they are more common, cheaper & give better coverage over the whole width of the tank. I use 4 x 40w T8 fixtures over my tank & I am yet to find a plant that this isn't enough light for. You could also use 4 x 40w T5 fixtures to achieve the same amount of light but take up less room. T5HO fixtures are much more expensive than standard T5 & T8 fittings. 2 T5HO fittings should provide you with enough light to grow most things. 3 T5HO's will be enough to grow absolutley anything.

You may want to do a diy hood to accomodate all these lights & save some money or you may prefer to just buy proper aquarium fittings that you can stick straight on top of your tank. The choice is yours.
Here's link to a site that you should find quite helpfull
http://aquaria.net/articles/lighting/
& pictures of my diy stand & hood with the light fixtures. I have used standard T8 shop fittings as they are by far the cheapest thing to buy. There are only 3 fittings in this picture as this was taken as I was installing the fourth fixture. You can see the space in the front of the bonnet style canopy where the fourth fixture goes.

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Marc M

Thanks That will be a significant investment. Maybe I will just install Moon LED's for now!!! Now I know what to ask for come Xmas time. Thanks

eiginh

Check this site out. http://www.ahsupply.com/ You can build your own lighting fixture and they'll supply you with the retro kit.

Nutter

It's not as bad as it sounds if you can design your own hood so that you can get the fixtures up away from the tank a little to allow for air to circulate & avoid moisture issues, then you can use standard shop fittings like I did. All up those fittings cost me $60aus & then the tubes cost me another $70aus. The whole lot, stand, hood & lights cost me $210aus to build. You can get cheap lumber from a demolition yard or discount lumber yard. That lot was put together with a drill, handsaw, screwdriver & a spirit level. No other tools were used other than a paint brush. You can also use shop fittings with the plastic covrs over them & mount them on steel brackets that slot onto the rim of your tank. A mate of mine did that & it works very well. It only cost a few extra dollars for the covered lights & you will only lose a small amount of light through the covers. Cost him $80aus for his lights & brackets. Next time I visit him I will get pics of his tank & lights & post them for you to see.

Marc M

Thank you.