monster in my water tank i need help

day 12
50L tank
air 7.8Lpm
Water temperature 71
ph5.6
450 ppm
I have useing a 9w uv ligh in the water for 2days
Turn off for one day
Today i open to check again
Something like jellyfish
Is all around the air stone and root
Almost everywhere
Can someone tell me what this is
How to fix it
please

Is look like this

I'm sorry I have no idea what you are dealing with but want to know too.

watching

它是根腐病 ？

i have adding Hydroguard 30ml on day5

so you use hydroguard as beneficial bacteria and you use uv to kill all bacteria.

that could be your problem.

i'd clean out everything with hydrogen peroxide or chlorine.

use hydroguard or uv bulb, not both.

Thanks
I have clean it all up and change in the water now
Let see what happen

Lol it did look like a jellyfish before I enlarged the pics

Whoa

throw that out, rinse off your roots.

I use clear REZ, there is lots of options, but yeah totes gross.