What happen

[rickyjohnlow]

I had set up my 2ft tank for about 2 weeks than small amount of fishes and plants are triving well and the water is crystal clear.
Then I add 100 malayan prawns and about 20 more tetra in, then discover that the water turn chalky.
Maybe say 30% down from crystal clear. But all life in there is still doing well.
What happen??

[|squee|]

My hypothesis is that the all the extra waste from 100 shrimps and 20 tetras are causing a bacteria bloom, or a bacteria bloom was going to happen anyway because your tank is less than a month old and newly-setup.

Bacteria blooms cause a white cloudiness in the tank.

[rickyjohnlow]

so is there anything I can do now?

[|squee|]

Frankly imho 100 shrimp with 20 tetras in a 2ft tank plus previous livestock is way overkill, even if your tank is planted.

I'd reduce shrimp count to 20 max, and fish count to 20 max. Bacteria blooms usually clear up once the ecosystem in the tank settles down. Search the Internet or this forum for bacteria bloom.