They really are lovely - very colorful.
As long as you are looking at basking areas for your turtles, here's a link with some good examples of different types, including some made of cork bark. If you use bark (and it works very well - turtles feel at home on it), be sure and get some that's never been chemically treated. Also, it should be wood that holds up well in water. Cork bark is ideal and it's very buoyant as well so the turtles won't sink it. However, if you can't find cork bark or good driftwood, you could make your own platform from plastic materials. I think there are some examples on the link and if you want to hear from people who've built their own platforms, just say so and they will be happy to share their experiences with you.
http://www.redearslider.com/forum/viewtopic.php?t=15260
On the light, if they are able to bask in direct sunshine for an hour a day that will be fine. In fact, no light bulb is as good as natural sunshine. And where you live, I would think the quality of sunshine is very good. Are your turtles pretty good baskers? They do need to dry off completely just about every day. When the weather's sunny a turtle living outside will bask for a large part of every day.
Your brand of turtle pellets is a reputable brand. Your turtles should be fine with it as long as they get their veggies (red leaf lettuce, green leaf lettuce, occasional carrot, tomato, berries, sweet potato, bell pepper, etc.) and an occasional high protein treat like a worm or shrimp. Do they have cuttlebone to snack on? Cuttlebone is normally provided to caged birds but it's also an excellent source of calcium for turtles.
Pyramiding like Totti has is often thought to be caused by excessive protein in the diet, like too much meat or shrimp, or too many high protein pellets a day. Just be careful about the amount of protein he gets and be sure he gets a balanced diet including green leafy veggies.