Lighting And Tank Depth

[ELKDOG]

What do you guys see as more important, the watts per gallon rule of thumb, or watts per the depth of the tank. It seems to me that it makes more sense to have the right amount of light for the depth since the light wavelength deminishes through the depth of the water. I have an AGA 150gl tank with 220 watts of pc fluorescents. low light plants do great (java fers, java moss, and anubias spec.) but having no luck with others. any help?

ELKDOG

 

[djlen]

You are running with less than a watt and a half per gallon. That's a low light set-up. Many people try for 2-4 watts per gallon if you intend to grow high light plants, and although you do lose some intensity through deep water, I would think that it would not be enough to stunt growth at 2-4 watts per gallon.
Len

 

[plantbrain]

Are these A&H lights with those reflectors?
These tend to be pretty good. I've grown pearl grass, hairgrass etc at less light at 24 inches deep using these. Growth was slower than with more, but the plants grew pretty good.
Most 150's are 24" deep.
220w = 4x 55w lamps and a 150 is 60 or 72 inches long. There is a 150 shape that's 30"T and 48 L x 24D etc. Even light spread would help there.
You can move the java fern/moss over to ther darker aeras and polace the other plants in the brighter aeras.

Do you have CO2?
I would go about this by dealing with CO2 levels first. Make sure there's 20-30ppm for the entire 12 hrs the lights are on.

Once that checks out, move on to NPK and GH. If the GH is 3 or higher, you don't need to worry about it. KNO3 is added for N and the extra free loafing K which is always good to have some excess. 5-10ppm f NO3 is good. KNO3 is cheap and a little goes a long way like all the macro nutrients. K2SO4 is good to top off the K levels. SO4 is also a plant nutrient often found in tap water.
KH2PO4 or NaH2PO4 are often used to add PO4. Both can be bought cheaply. The NaH2PO4 is sodium phosphate, Fleet enema's have this as one of their main ingredients. You can get all of these at www.litemanu.com
NO3= 5-10ppm range
K+ 20-40ppm range
PO4 .5-1.0ppm range

Then all that's left are the trace elements(iron etc).
I'm hesitant to give a range but rather a frequency to tank volume dosing.
25mls 2x a week of something like Flourish would be about right.

But if you deal with the NPK(Doesn't cost much, rather easy to do) and the trace, that will make the tank over all look better and the plants you already have.

CO2 is a bit of an issue if you don't have it. You will not use the above nutrient routine nor will the plants do much better unless you deal with that issue first, carbon is about 40+% of the plant. Limiting that will limit everything.

But the general idea if you want your tank to look better is to work on the CO2, macro and trace nutrients first. Then see if things look better before you add anymore light.

If the CO2 and macro/traces are off or out of whack, then adding more light will cause problems, not help. Working on the CO2 NPK etc will make your tank look better _either_ way. So do that first, then try adding more light if things don't look like you want.

Regards,
Tom Barr

 

[ELKDOG]

thanks for all the advice!