mineral spa sanitizer vs silver ion purifier?????

[Dee Dee]

I have a 2004 Sundance Opitima Spa.  I am trying to understand all the chemicals and I think I understand everything but these two items.  I bought the hot tub used so I don't really have a dealer to ask.

I have a little blue square cartridge called a sunpurity mineral spa sanitizer in the gate in front of the filter.

Then I have yellow long skinny tube like thing called a Nature 2 natural mineral purifier - continuous silver ion purifier inside of the actual filter cartridge.  

Are these the same things?  Should I continue to use both of them?    If not, which one should I keep using?  (I know they both need replaced after 4 months.)

Any insight would be greatly appreciated.
Thank you,
Dee Dee

[Vinny]

They are the same with the Sunpurity being the Sundance version of the N2. You should only use 1.

Take your pick and if I were using either I would choose the cheapest product.

[tony]

If they are both in your water now and wet, they can't be reused so keeping both for these four months won't do any harm.  If they haven't been used then save one for next four months.  Right now I am using a regular N2 cartridge.  I have been using the Sun Purity and have used the Spa Frog, anther manufacturers version.  The spa stores in my area tend to sell all three for the same price, so I take my pick.  I may try ordering in quantity online next.