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I got in a bit of a discussion about the wpg rule at work today, so I thought I'd bring it here. The setup under question is a 10g tank with 2 x 17w NO fluorescent bulbs with decent reflectors.

Would you in your opinion/experience consider this 3.4 wpg tank a high, medium, or low light tank? If you don't think this is a high light tank please drop a couple names of plants you wouldn't expect to grow in the setup if supplied with every other need.

I personally thought of this as a medium light tank. I figured that rotala wallichi or macrandra and other such plants wouldn't grow in any tank with only 34w of light. My experience leads me to believe that smaller tanks need more wpg than larger tanks, no?

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Critical Fertilator: The Micromanager of Macronutrients

Very interesting question and I do not want to imply that I should feel entitled to give an opinion about that at all considering the stage my planning is at. however, while surfing the web I came across some European sites, commercial and hobbyists only, that seem to be very successful with about 2.5 wpg for plants that are according to tropica very high light.

Anyway, IMHO 3.4 wpg are high light. Looking forward to a discussion.

I personally thought of this as a medium light tank. I figured that rotala wallichi or macrandra and other such plants wouldn't grow in any tank with only 34w of light. My experience leads me to believe that smaller tanks need more wpg than larger tanks, no?

matty,

Of course all that follows is only my opinion.

- Yes, I would say it is medium light at best. Loads of light will not even reach the plants but get lost to the sides. There is some reflection of the glass walls back into the tank (btw, that is why a tank with tall plants on the sides has effectively less light than one with low sides, at least as long as the glass is clean so it can reflect rather than absprb the light).

- In general, I would consider a 10wpg small tank to be high light, well maybe 7wpg as it is a 10G and not smaller.

- Rotala wallichi or macrandra may grow in the tank, at least the macrandra could. Why - well, macrandra is more in need of high nutrients (I think N) than high light. Usually, people with high tech, and as such high light (most of the time), tanks tend to add nutrients in some form. That is why the plant grows for them. Or not, as if you run a PPS (or some abbreviation like it, forgot the letters) ferting schedule, the plant may well die off over time.

- The one plant I think you would have trouble with growing in such a setup is HC. More and more do I conclude that it needs high light the most, over all other aspects (nutrients and CO2).

That's it for now,

Ingo

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Proud Member of the New Jersey Aquatic Gardeners Club

Yeah I would have to agree that it's somewhere in the medium light range. On my 5G nano, I'm running an 18watt cf bulb which gives me 3.6wpg and I would consider it medium. I'm growing riccia no problem and the rotala r is keeping it's reddish hues. I think the height of the tank is a hugh factor. I mean you had a custom 10g that was very shallow I think you would move up on the light intensity scale. I'm going to try and grow HC in both my 72g and my new 46g, but I'm a little wary of the depth penetration abilities of the my cf bulbs on both my 72g(3.6wpg) and my 46(4.2wpg) despite the large wpg on these good size tanks.

My Scapes

Interesting! wOould somebody please enlighten me what HC stands for??? I saw something very small, green and completely unidentifiable to my untrained eye in LF's log

i would call it medium to low light in my experiance there isnt all that much difference when more then one light is used it simply spreads the light out it doesnt make it much stronger at all...

For instance one tank with 3 T8NO tubes is not going to be as effective in keeping highlight plants happy as a tank with 1 Compact fluro tube... that is presuming the tank isnt very wide and the light can somewhat effectively get across the width of the tank...

so in short

2x 18 watt T8NO = medium - lowlight with excellent distribution of light...

1x compact fluro = medium high ligh with poor coverage...


if that makes any sense :

Edit: Also depends alot on how good the reflectors are...

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''All the clown fish and yellow tangs in the world cant save you now!''

HC = hemianthus callitrichoides



Yep, these are NO tubes, and the tank is a standard AGA 10g, which is 12" tall I think. The reflectors aren't anything special, just white paint in a sort of arch shape.

Thanks guys, it sounds kind of like a confirmation of my thoughts .

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Critical Fertilator: The Micromanager of Macronutrients

Matty;

thanks for the education A plant I will avoid!