my lillypads arent gowing? any ideas?

ive had these lillypads for around a year now. when i got them they had the typical pads but they didnt reach to the top of my tank. well now they put out leaves but the leaves dont grow out to much, and they look different. there is low flow where they are.

55 gallon tank

216w of T5
2x6500k
1xactinic white
1x redder bulb (i forgot it exactly)

79-80 degrees
ammonia: 0
Nitrite: 0
Nitrate:20

dose with Flourish Excel (twice normal dose), and flourish (twice normal dose). water is well water (high in iron). and i do twice weekly water changes at ten gallons each.

here are some pics showing whats going on, pardon the hard water build up, i need to get a razor and clean that off..:

im just trying to figure out what is making them not grow. any ideas?

 

What is your phosphate at? Those guys love being in the sand. They will also love having root fertilizer.

 

i do use root fertilizers on them. i dont have a test for phosphate. and he is in the bottom of a two liter with sand in the bottom. it looks like the sand may have all fallen out so ill put more in there.

 

That would be the problem.

 

what should i change?

 

Put something in the bottom of the bottle that will prevent the sand from sliding out and all should be good.

 

Ok thanks! Ill switch the whole bottom out. I put holes in it thinking that would let the roots grow, but i didnt realize all the substrate would fall out -.-Thanks a lot!

 

it looks like you almost have dried out live rock in your tank as decoration? that actually looks pretty cool.

 

BTW way to use the rock for planting.

 

Thanks guys! And yes its all live rock from a previous salt water tank. Whenever my algae problem pans out ( by the end of the week) ill make a thread for my tank!