How many watts over a 20gallon long?

[Vmax911]

I'm setting up a 20 gallon long planted tank. I'm going the cheap route, and will be using screw in type Fluorescent lights. I did find the non-spiral type. However, I know that the pg rule breaks down for small tanks (is mine in thatcategoryy?) and that I will loose some efficiency due to restrike (even though not as much as the spiral type.

I am making a DIY hood, and figure I could fit four 20W lights pretty easily. This will give me 80W, minusinefficienciess, over 20 gallons. Will this be sufficient? Too much? I want to be around a typical 3pg or so.

Also, I will be dosing excel. Will that be sufficient, or will I need to still do a DIY CO2 system? If sufficient, should I just stick to the recommended dosing schedule?

TIA

 

[JDogg]

i think that should be enough light. you will need a carbon source. excel might be ok, but might want to just do the DIY Co2. also look into EI dosing method.

what kinds of plants are you thinking of keeping some are more demanding then others.

 

[Vmax911]

i think that should be enough light. you will need a carbon source. excel might be ok, but might want to just do the DIY Co2. also look into EI dosing method.

what kinds of plants are you thinking of keeping some are more demanding then others.

So I guess CO2 injection is more potent than excel? Is there any type of wpg limit that excel will not be effective at, or do you just dose more?

Honestly, I don't have any specific plans in mind. I had a low-light, non CO2 tank that I tried planting and didn't fare so well with. But I was able to grow every type of algae. I want a smaller tank that will be better for plants. So I got some eco-complete, dry ferts, excel, and the lighting mentioned above. I'd like to be able to grow most plants, which I hear 3wpg will allow. Any chance I'll be able to grow carpeting plants with this setup?

 

[Purrbox]

Excel will be effective at any lighting level, you just won't get as nice of growth as with injecting CO2. It can also be rather expensive, especially in larger tanks. In a 20 gallon it probably wouldn't be too bad. You can dose more, but you have to be careful as dosing too much is harmful to plants and fish. There are some plants (Anacharis and Vals) that known to often have problems even at recommended dosing levels.

With the screw in flourescents, you may or may not have much luck with a carpet plants. You'll probably be able to grow them, but they have a good chance of becoming leggy. I'd go ahead and try them and see what happens.