Brown Spots on tank silicone

[splatsplatsplat]

Hi, new to aquariums, have tried googling the answer but always seem to get conflicting answers.

tank is 3 weeks old, and am getting these brown spots only on the silicon joints where the glass meets.......

bit of background if needed....

I have a 78ltr Corner tank (aqua one ufo 550), we filled the tank up and added some water conditioner, filter on & waited 4 days before buying some neon tetras. The day we bought them, the water was slightly cloudy, but the water cleared up after a few days and has since (3 weeks on) been crystal clear. waited another week, then bought some danios, mollies and a yoyo loach all 3-4cms.
The tank is kept at a steady 24-24.5, been feeding twice a day, a small pinch of flakes each time which all get eaten quick. havent got any testing strips, and have heard about ammonia/nitrites etc.

Are those spots good or bad?

I also have another question regarding changing water...do you have to get the fresh water to the same temp before adding it to the tank, or even let the water sit for a few days?

Thanks for any replies

 

[Ches]

Dunno what the spots are, but could be algae? Does it come off if you scrape it? The changing water must be the same temperature as the tank water so you don't shock your fish. Add dechlorinater to neutralize chlorine/chloramine/heavy metals. If you let it sit for a few days, it'll also become safe for the tank but will be too cold so you'll need to heat it first which is a hassle.

 

[Fishkeeper26]

It doesn't look like diatoms

 

[splatsplatsplat]

Hi guys (& gals?) thanks for the above. I have been getting free water tests at the local shop, but have just bought my own api master set to understand the process better (plus I have a poorly gardener killifish) I treated the tank last week with aquarium salt, and I have also recently removed the carbon (due to change it anyway) as I added some King British Disease clear treatment. 2 of the neon tetras have some sort of parasite in their chins in the shape of a small white bubble - from googling Ive found others with the same problem, but the worm inside the bubble escapes after a few weeks (I'd like to keep separate them but i dont have a spare quarantine tank atm) and the tetras suposidly recover without loss, so just kept an eye out for them. but when the killifish started sitting on the bottom (for the last 4days) and not sure why, I wanted to make sure the water quality was ok.

This is my first test, can you guys just scan it and tell me if the ph is ok? (apart from water change - not sure how to reduce it - some people say reducers dont work very well - or make things worse afterwards) I think im happy with the rest of the results, not sure if the nitrate is ok (i need to do a 10% water change after the disease treatment ends anyway)

as for my killifish, he's been fine for several weeks, but in the last 4 days hes been lying on the bottom, he hasnt bothered eating for 2 days even if food is right next to him - he does swim a bit when other fish bother him but always returns to the bottom after 10 seconds, and his breathing is faster than normal (have been putting air pump on for 4-6hrs a day for added oxygen?). I can't see any visable signs of wear&tear on him? and the other killifish are fine.