Corals looking washed (in a negative sense)... this is the 2-3rd day

[Katze]

Hello everyone !

First, by washed I mean irregular/weird/not fully opening

This is my ~100g tank with a +20g sump.
It is new, nearly a month old. Why so soon ? Well my other tank is hostile to any hard coral so death or transporting them were the only options.

Livestock: 1x Scopas that's it, nothing else
Parameters:
NO3: 1-2 (slowly climbed trough out the month, if it hits 5 actions are going be taken)
PO4: 0.04
kH: 9.6
Salinity: 1.026-25
Temp: stable 25.3

Filtration:
Filter sock
A skimmer designed for 500l tanks with high bioload it would be 300-200l

2 weeks ago:

Today:

Maybe the water is cloudy ? As I compare the photos it seems to be ! I'll get carbon to be sure.
Thank's for your reply !

 

[Spare time]

Turn the skimmer off during the day. If they are pale in coloration, usually that is a sign they are getting insufficient available nitrogen or phosphate.

 

[Katze]

I compared pictures (+took higher quality ones) and no sign of becoming pale... what's next ?