Everything turning brown in 75 gal sw tank

[motorzrcook]

Hello everyone, i been reading a lot of the posts here and you people are very friendly and helpful. I have a 75 gal sw tank and its now done cycling, i have a couple pieces of live rock in it and i have 20 pounds of dry rock. my sand is turning brown my dry rocks are turning brown and i'm getting brown spots on my tank. can someone please tell me what is going on? my water temp is 81.1 i use tap water that i add prime to. i have a esshops psk 75 hob protein skimmer, its the newest model, pleae help, thank you.

http://i1294.photobucket.com/albums/b610/motorzrcook/100_0381_zpse564d7e2.jpg

http://i1294.photobucket.com/albums/b610/motorzrcook/100_0362_zps272adad6.jpg

http://i1294.photobucket.com/albums/b610/motorzrcook/100_0387_zps9077a369.jpg

 

[motorzrcook]

i hope im posting the pics the right way.

http://i1294.photobucket.com/albums/b610/motorzrcook/100_0387_zps9077a369.jpg

http://i1294.photobucket.com/albums/b610/motorzrcook/100_0362_zps272adad6.jpg

http://i1294.photobucket.com/albums/b610/motorzrcook/100_0381_zpse564d7e2.jpg

 

[Crystal A]

Diatoms. Perfectly normal. They will disappear once all the silicates in the tank are used up.

 

[ivan_dalmatia]

More flow may help as well

 

[motorzrcook]

thank you

 

[Bectan01]

Agree diatoms. For future reference I recommend using ro-di water, you will run in to trouble using tap water long term. Do you plan reef or fish only?