general plant question sometimes turn brown or yellow

[bacala]

some facts: 150 gallon freshwater with 4 x 96watter compact, 12 hours on

If a plant turns borwn or yellow...mainly at the "edges" is this a general sign of:

not enought light
not enought nutrient
not enough???
or too much of???

Sincere Thanks in advanced for the help and direction fish buddies!

 

[QTOFFER]

Moved to FW-Planted tank forum

Brown or yellow leaves are usually due to either a nutrient deficiency, or too little light.

 

[malkore]

You probably have enough light for the plants you are keeping, so I'd say a nutrient deficiency.
Here's some info: http://www.csd.net/~cgadd/aqua/art_plant_nutrient.htm

 

[shannen]

Try dosing iron into he tank. Thats normally the cause of browning leaves who get enough light and KNO3. Potassium added will also help the plants take in the added iron.

 

[travis simonson]

Are you supplementing with CO2? You have a lot firepower with that much wattage and if you don't have CO2 you're looking at pea soup Believe me I tried it - things didn't turn out that well until I got pressurized CO2.