[MatthewR]

Ok, my tank has been running for about month now, I have alot of brown algae, I clean the glass about once very 3 days, and leave the back alone. I have heard never clean the back glass part, is this true? and I have a bunch of live rock in my tank, there was alot of purple coralline already on it, I got it from a friend, but it seems to been dieing? The purple is losing its color little bit, by little bit, I am about to do a water change, I have not done one yet. I have a 75G and going to change 20-25 G out. Is this brown algae going to start turning green soon? and then hopefully move on to red or purple? I have some MH lights with some blue lights on the side of it. Any help as to the brown algae thing would help. and How high will the nitrates go during or after the cycle. Mine are high from what I think. Somewhere are 10-15 on the color chart. I hope the water change will brings this all back down.

[Taras1]

Brown Algae, aka Diatoms, are part of the cycling process. They are dependent on silicates. It's important to use RO/DI water to minimize this nutrient. Nitrates should level off below 10 in a few weeks.
Have you added your clean-up crew yet?

Hang in there -- patience is a virtue...

[Phayes]

Yes, once the nutrients in your tank have been depleted, the diatoms will be reduced to minimal/non existant levels... and then you get the wonder of the green algae.
In response to your concerns about the liverock and the loss of your corraline algae: Any change of lighting conditions will cause a massive change in the symbiotes that inhabit the actual corraline algae. These symbiotes are what gives corraline its red/purple color. Any increase/decrease in light intensity or light duration can cause this change. Luckily, after a couple weeks, and your photo cycle is on a normal pattern (invest in a timer if you dont already have one), your corraline will start to repigment itself. This hobby is about patience and waiting... and waiting.... and waiting. And just when you thought you've waited long enough, you wait some more (And then a little more after that).

[Phayes]

By the way, don't do that 25g water change you were speaking about. Let your tank fully cycle before changing any water. In the mean time, keep an eye on your ammonia/nitrites/nitrates. Once your ammonia and nitrites have peaked and gone down to 0, and once your nitrates are slowly starting to build, you can do that water change (however I don't think i'd do a 25g waterchange).
Unless you have inverts in your tank, like a clean up crew, and then you dont want that ammonia or nitrites spiking too high. But if you were serious about this hobby, you wouldn't put inverts in a tank while you were cycling... wait until you see that green algae before adding any type of clean up crew... and make sure your tank is cycled.
Enough jibber jabber, you get the point.

[Br14n55reef]

I agree with all replys