Your plant is Egeria densa and it has difficulties adapting to your water-quality. The "see through" leaves are dying/dead - but it look like the new growth has adapted to your water-quality. So you can cut the stems just under the (upper) part, looking good. Remove lowest leaves on your cuttings and re-plant those cuttings within the group of stems.
I'd be very surprised if the remaining stems would not produce new shoots, too, since Egeria is really very good at adapting (though often loosing some leaves, like your plant). If you find the "bare" stems unsightly, just dismiss them, leaving only the better looking re-planted cuttings in your tank. Once settled, Egeria will grow very vigorously, contributing to the cycle and maturing of your tank. You will need to trim the stems often, though.