Frog Pool Cartridge Plug

My wife went to the pool store to get some replacement cartridges for our chlorinator only to buy the wrong one. She called the store and the ones that we did need they didn't carry anymore, and she had to order from online.  I had never looked into this before since she usually handles it but she was frustrated cause we had to wait, and on top of that they were a bit pricey.  I tried opening the cannisters but didn't seem to be able to, but after looking around a bit it seemed like the best thing to do was to just put a hole in the top and plug it up.  

I used a 2 1/8 hole saw bit to put the hole in the top and printed this with support to make it easy to clear the hole out.  Now we can just use cheap chlorine tablet bits and it works good as new.
 

Print it with supports and clear out the remnants, should just be able to slip it in over the hole lip and let it sit there.  I included the lip because a few times I pushed it in too hard when testing it and it can help pull it back out.