The water level seems a bit low, be sure to top it up mid-week or every 2-3 days. Keep some distilled water in the fridge to use so it will also bring the reservoir temperature down when you top it up.
The brown does look like it’s a bit more than just nutes when considering the past photos, but it doesn’t actually look that bad – you’re at the verge I’d say (somehow keeping it at bay). Have you been using any additives or extras (like hydroguard)?
To me it looks like the room temperature is still a touch too warm, your water temps are at 73-74°F but you want them at 70-71°F. If that little trap door on the back of your unit is installed, I’d suggest to remove it and angle a fan so it blows cooler air toward the back of the grobo, specifically into that hole. That dropped my reservoir temperature by 1-2° in the past.
Additionally, I don’t see the grobo grow light on but you have the door open. If that was immediately after the lights shut off it’s probably ok but in general we do not want to disturb the sleep cycle at all, not even for a minute to take a pic! That can make the plant revert back to a vegetative state or cause it to start throwing seeds (aka hermie/hermaphrodite).