Amazon swords only 3" after 2 years! Is algae stunting growth?

[spinmaster]

The tank:

Eclipse 12 (I think 13W bulb - 3 years old)
Light stays on 9 hours a day - No direct sunlight
9 tetras(neon, cardinal, skirt)
2.5G water change/week
add 2.5mL pH down (Keeps pH around 6.9)
add 5mL aquarium pharm. plant nutrients
add 3mL aquarium pharm. dechlorinator

I have had the amazon sword plants for around 2 years. They keep sprouting new plants but the plants just do not get big. The longest leaves are between 3"-4". The leaves have been getting covered in algae though.

What steps should I take? I was thinking of reducing the amount of light to kill the algae but then maybe there won't be enough light for the plants...

Then I was wondering if the pH down is causing the algae. I just didn't want to leave the tap water at 7.2 pH with the tetras.

Is it possible that I just need to change the eclipse bulb?

TIA

[spinmaster]

Whoops! I just remembered the plants are Java fern and not Amazon swords! :egads: Everything else is accurate...

[tropfish]

well, Java Ferns are extremely slow growing plants in low light conditions, so it's easy for them to get algea growth. I would up the light wattage to al least 2 watts per gallon if you want faster growth.

[spinmaster]

Yeah, I don't think I can up the wattage since it is an eclipse tank. I'm considering adding laterite.

[zeon]

From my reading and experience it is recommended to replace your bulbs once every year, so if you are running on the same bulb for three years I would say yes, replace the bulb. The compounds in the bulbs tend to burn out, so even though they are still bright and lighting, you might not be getting the same specturm of light. That could be why the algae, I had the same problem when I first started plants way back when. For about a year, they grew and flourished then after that hair algae and wiped out the whole bunch. Also you might have a smaller variety of sword plant. I would change the bulb. Just my 2 cents worth. HTH. Some one smarter than me can tell you more. :)

[spinmaster]

Yeah that does make sense. The bulb was a year old when I first got the plants and they were doing pretty well at the beginning.

I'm going to order laterite and a new bulb...