My recommendations, Nordbad, (as it's close to me), but also there is a Dampfbad there which is a non-nude as it's open to the general swimmers, although gets very crowded, unless you go in the day time

The sauna bit is also good. Volksbad, my fave sauna place, art-deco- roman greek thing going on, but the pool is naff for swimming...
You'll be hard pushed to find a decent non nude sauna in Germany, as they think it is unhealthy to sit in your own sweat in your cozies. Also make note of the sign in the sauna showing you how it is done, i don't bother personally but i have been 'told off' for not following the correct, shower, sauna, cold shower, relax routine...! go figure! My problem is that i don't understand the pictures! Mind you spending 3 hours in the sauna is easily done, take some reading material and relax and enjoy. This is something the Germans have got absolutley right, and suprisingly they are not up tight and stiff (pardon the pun) about it and they are all friendly, saying hi etc when you enter the sauna...must be something to do with the equality of nakedness, if you have never tried it, do it once, it is quite liberating, and then you'll never go back to wear togs again. The UK is so prudish!!
Guys, there is no chance you getting...ahem excited it too darn hot!!! There is a medical reason why if you are interested!
If you want to try and avoid the lechy guy types then try girl day only sauna that most pools do, or go during the day if you can when it is not too busy. Of course the girl only days applies to girls only..sorry guys...