Mouse,
The red stuff looks like cyno-bacteria to me. The little brown specs on the sand might be diatom-ish, but it is hard to tell from the pictures.
Some tank specs would help. Are your nitrates high? Your phosphates? (I would bet on those being high) Also how much circlulation do you have? Do you use tap water? Many times cyno is just a result of not enough flow in the tank and/or tap water usage (high phosphates in the tap water). I belive diatoms are caused by high silicates (again, often found in tap water).
Do a quick search on cyno bacteria and diatoms and see if those look anything like what you have. Also, try and list some more tank details so we can figure out what is causing this.
HTH
Stewart
ps - do not stress about this, it is fixable once you manage to figure out what is causing it.