Why Is The Wpg Rule Of Thumb No Good For Smaller Tanks?

[pseud]

Just trying to understand mathmatically why the wpg rule isn't really applicable to smaller tanks...

 

[George Farmer]

Here you go mate.

http/rexgrigg.com/mlt.htm

 

[pseud]

Perfect. Just what I needed. Thanks dude.

 

[Jen]

I have always wondered the actual reason.

How do I find the LUX of my light? it's not the 6500k, is it?

 

[pseud]

No, the 6700K is the color temperature.

The lux is the number of lumens per square meter. I think you have to check on the bulb or the box or the website or something for the lux rating...

 

[pseud]

You know, I understand why it doesn't apply now but, confused about something else... how to figure out what is considered medium or high lighting for smaller tanks...

specifically, a 5.5 gallon that I just picked up and HAVE to plant lol

 

[kenneth_kpe]

how about a rough estimate of about 40 watts ? i think that would be med-high ? i hve 23 watts over 2.5 gallons and the glosso compacted nicely before.... i thinks its more of a guessing game unless you look at what other people did try checking out the lighting levels of the guys at the AGA contest

 

[pseud]

Hmm.. what are the dimensions of your 2.5 tank?

 

[WendyinWichita]

This is so strange. I have a 10 gallon that just has the standard hood and light, 15 watts I think. I have water sprite and Hygro Polysperma in it and it grows way better than in my 55 with 170 watts. Not one bit of algae either.

I can't imagine water sprite doing so well with such low light if all of this is true. Guess I shouldn't question it, just enjoy it.

The bulb in the hood isn't even a good one, just an Eclipse bulb that came with the hood.

I don't even add fertilizers to that tank, I just have a sponge filter in it because it is full of fry. I assume the plants are feeding on the nitrates produced by all the fish waste.

Lucky me. Knock on wood.....

 

[EliteFishy]

I have 130 watts over my standard 29 gallon tank. Is this ok?

 

[George Farmer]

I have 130 watts over my standard 29 gallon tank. Is this ok?

Too much light if anything. 4.5 WPG is a lot of light in a 29G, even for the experienced planted hobbyist.

I assume you have CO2 injection with appropiate fert dosing and plant density/growth (bio-mass)?

The WPG rule works fine with tanks over 15-20G. See the pinned lighting article.

 

[EliteFishy]

is 65 watts enough and Will 130wwatts harm my plants?