Sensitivity to smells and a true allergy are different, but I totally understand where you are coming from.

Over the years I have become less and less tolerant of perfume and other chemical odors.
When one "smells chlorine" from a pool - it's the CC in the pool that you "smell"
not the FC. The combined chloramines can be oxidized with appropriate levels of FC. So if you smell chlorine, the pool doesn't have
enough. Clearly water balance is the issue when someone smells chlorine. This is usually the culprit in indoor pools, this is usually the culprit in pools where proper chlorination is not being monitored.
It will be an especially bad problem, IMHO if one used an ionizer and kept the FC at the recommended .5-1. It simply isn't enough FC residual to prevent CCs from forming and the N2, while it may keep algae away, will result in copper staining and will turn blonde hair green. The N2 may keep algae away, but it won't work on bacteria and viruses fast enough to be practical for use in pools. And if the pump is not run enough, or the FC is allowed to drop to 0 (easy to do if the residual is only .5) algae can take hold rather quickly, despite the ions. The manufacturers suggest shocking the pool weekly to keep the CC away, but that is not always enough. For example, CC's can form on say-day 2, and if you don't shock till day 6 or 7, you'll have the irritating CC's the full 5 days....
I have experience with this as I had a Pool Frog which is similar to the N2. I used it for 5 years and am quite familiar with the pros, but especially the cons.
Since I switched to BBB 2 years ago, I have never had CC's form, never had algae, never smelled a stich of chlorine, even when I shocked my pool! The only reason I had to shock was I was going out of town for 11 days and wanted to prevent the chlorine from dropping too low. The only other reason I shocked was for closing. That's it!
The N2 cartridges and the associated weekly shock treatments will quickly add up and you'll be right up there with Baq - expense wise.
If it were my pool, I would use straight bleach, set my CYA for 30 and keep the FC above 2 at all times, your target for dosing being 4...so that by the next night, the chlorine won't drop below 2. 2 is not very high at all and as long as you are diligent about it, you likely won't get any CCs and the associated smells, and you won't have to shock. Something to consider.
