Sand Bed Dirty Or Is It Some Kind Of Algae

[vjb71]

Hi

My 100g tank is just about a year old and over this period the sand bed has steadily gone dirty with the colour changing from white/off-white to brownish. This is despite me using a gravel vac to stir and clean the sand every fortnight during my water changes. However that doesn't seem to be helping. I have also tried using a bacteria based product to lossen dirt and grime with the hope that it would help, but no results. A second issue I face is a reddish growth similar to coralline algae between by sand bed and glass growth. Don't know how best to clean it without moving lots of sand and upsetting my corals and rock work.

I would appreciate some feedback and help on this. Is it actually only dirt or some kind of algae/bacteria and how do get rid of it. Pictures given below-

 

[cloak]

It looks normal to me. Your substrate looks more like gravel than it does sand, so given time those larger grains will turn all kinds of colors. Pink, red, or purple being the most prominant. The algae growing in between the sand and the glass is normal too, but if you want to try and get rid of it, you could try sliding something like a credit card down the front of glass.
Just to give you an idea, I spread a thin layer of Puca shell over the top of my sand bed one time. Here's what it looked like after awhile. What your experiencing is nothing to be too concerned about IMO. GL.

 

[Dan_P]

Looks normal.

 

[Reefer4evaa]

Looks like cyano algae developing by the front glass...this happens from light penetrating thru the glass.not a big fan of crushed coral IMO..too much detritus build up

 

[vjb71]

Thanks for the feedback everyone.