Ricca turning black

[Decarn]

I manage to grow my ricca from 1 small wire mesh to about 5 meshes now. But then, some of it starts turning black and a lot of it floats up.

I've listed a few possible reasons but I need the expert advice from all of you.

1)I must admit that I was too caught up with my work and had not change the water for 2 weeks. There is a lot of algae and I also found one of my tetra to be missing.

2) Too much ricca floated on top and block the light?

3) My DIY C02 stopped about 5days ago.

4) I notice a white egg sack thing on my ricca, disease?

5) I'm using a overhead filter?

6) Lack of fertilizer?

7) My current 36W PL is not enough for my 2ft. I need to get another 36W?

I've no other plants besides ricca and I hope to do something soon before it all dies off. If it turns black, does it mean it is dead and cannot be grown again?

[Simon]

I think yr problem shld be lighting, fertilization and co2.. with yr floating riccia shading those riccia below, chances that they wouldnt get enuff lighting... r they turning black from the bottom up or at the top? never seen riccia patches turning black, almost brown .. can u reconfirm?

[Decarn]

It really turn black. I also dunno why?

[acidjc]

your ricca is dieing that y..

make sure they get enough LIGHT and fert.. change the water once a week (20% water change). if possible try to relocate your ricca to a spot with more LIGHT.. like put it higher , nearer to the light etc.

and of-cos'.. CO2 is v v important... Trust me!!!!!

[pipsqueak]

Overhead filter will cause more losses of co2 in the water, as it agitates the surface. i lost my riccia thanks be to the overhead filters.
And yea, i think they do better in 25c and below.