Please tell me whats wrong with my turtles shells??

Question
I have two RES turtles and both are developing this weird glaze all over their shell (top bottom and sides) for months.

It doesn't feel squishy, wet, stinky or leaking pus.

Can anyone give me a clear direction and please just tell me what it is??
1) Shell fungus
2) Shell rot
3) Mineral deposits
4) Shedding (normal and nothing to worry)
5) Retained scutes
6) Something else

Please visit http://phyllisquek.com/blog/turtle.html for the pictures of my two turtles.

Thank u!

Answer
Hi Glen,

It's always a little difficult to tell from pictures (but yours are very good!), but it looks to me like mineral deposits from the water.  Another clue would be deposits building up around the water line.  Shedding scutes don't generally develop that much of a white cast, and you'd be able to see the scutes start to lift.  If it's mineral deposits, you should be able to see that it lays on top of the scutes, and should be able to scrape a bit off with your fingernail.  Shell rot will eat into the scute, and fungus will be fuzzy and patchy.  I don't really see any areas where the shell is chipping or anything like that.  Mineral deposits don't hurt the turtle, but are unsightly.  Cleaning the shell with a soft toothbrush dipped in diluted vinegar may help to remove some of the deposit.  Be sure to rinse afterward.  

If the brushing with diluted vinegar doesn't help, another possibility is bacterial scouring, which is harmless and caused by the beneficial bacteria in your tank feeding on organic material (the scutes).  Reducing the bio-load (more frequent water changes, large enough tank and filter) will help with that.  Either way, I don't think you need to be alarmed.  Hope this helped.