I got the idea from here, but it's by fair the best way I've found to feed nori so far. Screw the clips and suction cups.
Buy some magnets(dipped so they are safe in the aquarium), a short piece of PVC pipe(3/4 inch and about 6 inches for mine), and a cap(optional, but I recommend it).
Glue a magnet to the end without the cap using super glue. Now you can put another magnet on the outside of the tank, and the pipe will stick out into the water no problem.
On
amazon you can find zip ties that you can release with a button. The ones I use are no longer available, but these are similiar and you get 100 of them for $7.
You can use a full sheet also, by just folding it over, but I use half a sheet at a time. Take a piece of nori, wrap it around the pipe as tight as you can, then use the zipties to hold the nori. Leave yourself an inch or 2 so you can put them back on easily, but cut off the excess on the ziptie.
No cutting, no worrying about them getting big chunks that float around etc. And the only parts they don't eat are the 2 little strips under the zipties. They stink real bad the next day, but I throw them in the tank when I'm putting the next piece on and the tangs absolutely love it. My naso is normally really shy when I open the lid, but when he see's that nori strip going in, he'll come all the way to the top to grab it before anything else can, then sucks it down.
Not sure if I could make it without it honestly.