In general there's no compatibility issue. Nature2 works by adding metals to the water that inhibit algae growth. They don't and cannot sanitize your water--chlorine STILL does that.

The idea of the erosion systems is by removing the growth of algae, a portion of your chlorine isn't consumed killing the algae and therefore you need less to keep your pool sanitary.

It sort of works--like banging your head against a wall because it feels good when you stop. But it adds metals (copper and silver) that can cause you a world of problem.

Then, there's the fact that Nature2 is highly secretive and describes how it works in very metaphoric terms and never once says it's an erosion system. That alone is enough to challenge ones trust.

The cartridges for Nature2 start at about $100. Even if you only buy 1 per season that's the cost of 5 carboys of 12.5% liquid chlorine--the equivalent of 50 gallons of bleach! If it doesn't at least save you using 50 gallons of bleach, it's not cost effective.

But, the good news is if you are already using some kind of chlorine there's no conversion to using B-B-B. Just take out the Nature2 cartridge. Even if you leave it in it will still work with B-B-B.

It's if you are using Bromine or Bacquacil that conversion is a problem, regardless of the Nature2.