Which type of Nature 2 vessel do you have? If it is the Express, the easiest thing would be to leave it it. But there is only one hole punched out of the pipe that wouldn't be a major repair.
I left a depleted Express connected to my pipes for years. My friend still has one attached to hers. (The express did not put out nearly the amount of metals the larger vessels produce so we both stopped using the express after one summer due to constant algae, which we didn't have using the larger vessels. Of course, using too little chlorine with our "magic" Nature 2's we both never had enough chlorine in our pools to really sanitize but with the larger vessels we, at least, didn't have algae when all around us battled it in the summer; mostly yellow algae.)
I switched from Ionizer Floatron to BBB last summer and won't go back. I had to do an AA treatment in the fall that lightened the metal stains from ionizer a little. The AA treatment did take care of the iron stains.
I have two concerns about leaving either of the vessels in place and hopefully our experts will comment. 1) How much head do they produce, both types, due to turbulence and 2) How long does it take to totally dissipate residual metals out of the cartridge? I want to keep as many metals out of the water as possible. I do have an ongoing addition of iron in pool from dust/sand/silt so I have to keep a metal sequestrate in all the time but it doesn't work as well on copper metals, and some others, as it does for iron.
My friend, hasn't used ionization for years, but with Express still in place (you can't remove the cartridge and leave it out like you can on the big canister type, unless you totally cut off water to that pipe). I'm going to have her take her water for metal testing to see if she has metals. She shouldn't but if she does it could be very little and from the Nature 2. She has a super duper water purification/conditioner/softener system but all outside spigots are straight city water without going through the conditioner.
gg=alice
