WPG Theory as it Relates to Smaller Tanks

[black hills tj]

I have a 29 gallon tank with a 65 watt CF fixture over it, and I would say, according to the types of plants I raise in this particular tank and their growth, that the WPG Theory holds pretty true to this size tank.

I have heard that the WPG Theory is distorted when you reach down to the 10 gallon tank size, and I also believe that it is distorted as it relates to the 20 gallon high tank size. My question is, just how distorted is it? I currently have a lightly planted 10 gallon and a sparsely planted 20 gallon high tank with stock fluorescent fixtures.

Since its October and Christmas will be on us before we have time to really think about it, I've been looking into alternate light systems for my 2 small tanks as Christmas gift ideas since my parents always seem to have a hard time shopping for me.

Shortly after Christmas, I will have upgraded lighting on one or both of my two smaller tanks. However, the intensity of the lighting may vary. I can vary on the types of plants I use according to the lighting I end up with. I have dry ferts if I need to dose, and a pressurized CO2 system is not out of the question as a Christmas/post Christmas item. What would you guys suggest for lighting on a 10 gallon and a 20 gallon high tank?

Thanks,

Mike

 

[neilanh]

My personal experience - I can't speak to the theory of the WPG rule, except to say that it's a guideline, not a rule, and YMMV.

I run all of my tanks very high light and high tech - it's just what I like to do. On my 29 I run 2x65W, and on my 20H I run 1x65W, and have had great results with both of them. I do use ferts and pressurized CO2 in both tanks as well.

The CO2 system is the key, IME.

 

[black hills tj]

I like to refer to it as a theory instead of a rule as well. I did consider moving my 65w CF over to the 20g and upgrading the lighting on the 29g. Like you mentioned, a pressurized CO2 system is what is holding me back.

 

[Purrbox]

For a 10 gallon, 20-40 watts will get you in the low to moderate light range. Going upto 60-80watts will get you into the High to Very High light range. If using spiral compact fluorescents you'll loose quite a bit of efficency due to restrike, so the light level achieved is a bit less.

 

[newfound77951]

Hmmm, I thought I had posted in here, but it must have gotten lost somewhere. I thought I pressed "post reply"!!

Anyway, I have 26 watts of CF on my 10g and I would also say it is just above low light. Grows crypts and Java fern nicely, I have some lower light stem plants in there now that seem to be doing OK (Rotala and baby tears). I do add some ferts but no CO2.

By the wpg "rule" the 10 has more light than my 55 with about 120 watts, but the 55 will grow almost anything except really light demanding plants like macrandra, and requires a little bit of CO2.

 

[An t-iasg]

Don't you just hate that when the computer eats your post!

For your 10 gallon tank, like Joy said, you have a few options on the light level and all the options will give you a nice tank.

I have 27 watts CF over a 10 gallon tank. I dose macros and micros each twice a week. I would consider this tank on the upper end of low light. Besides the low-light crypts and anubias, the stem plants I have are Bacopa monnieri and Limnophila sessiliflora. Hydrocotyle verticillata grows very well in here too. This tank has pressurized CO2; I keep it on the low side at 15 ppm.

Another 10 gallon tank has 36 watts CF. I consider this tank in the mid-range of medium light. I dose macros and micros each three times a week, and run pressurized CO2 at 30 ppm. The stem plants are Bacopa caroliniana, Ludwigia repens, L. arcuata, and Rotala rotundifolia. These plants do better in this tank than in the lower-light one.

I have a stem of Hydrocotyle leucocephala in each tank. It does well in each tank but it really gets larger leaves and more side shoots in the higher-light tank.

 

[SpeedEuphoria]

I'd like to add on my 10G I have used the stock 15w T8, 2x13w spirals, 2x 20w spirals and 2x 23w spirals.

I believe that the stock 15w tube is close to 2x 13w. I think the 2x 13w spirals seem a little more light, I would rate it at higher low light. Either one with 10hrs seems just fine at growing low light.

The 2x 20w spirals seems like around medium, prob lower medium.

All my tanks are non CO2 and my 55G with ~100w of T8 is prob a solid medium light and comparing both tanks the 55G grows roatla better than the 10G with any lighting on it.

Also want to say that like others have said, 40w of tube lighting should be more like med to high medium compared to the spirals as low medium at the same wattage. If your going to use "WPG" I think you need to compare it to the same type bulbs wattage. So 40w of T8 or T5 on a 10G is prob too much IMO on a 10G w/o CO2.

 

[Jchillin]

Here's a thought...why not try growing out a few varieties and check their progress? One should consider the tank to be similar to that of a garden and it's possible that mixing and matching in a smaller tank depletes others of nutrients, including light.