What kind of filters are they? Even if they used to do a good job, if they were bought for the size tank you have, as your turtles grow they'll become less effective (you need a filter rated for 3X the size of the tank).
Warmth, light and nutrients in the water from poop, debris, etc. all help algae to form (I'm assuming the green is the algae).
If you have your lights on more than 13 hours, cut back.
If you've got the tank in front of a window, move it.
What's the water temp? If it's high, turn it down to about 75-76F.
If your filters aren't doing the job they should, perhaps you should think about an even better one. To cut down on the nutrients in the water, do partial water changes.
As for the tank cleaning, diluted white vinegar and a good rinsing works well.

"You become responsible, forever, for what you have tamed." -Antoine de Saint Exupery-