ok, trying again, new 18' pool

Hello all,

I am the new proud owner of an intex 18' pool (previous owner of 16 foot pop up, til the neighborhood cats got to the ring, and Niagra wasa flowin>)
I am just topping off the last 1000 gal,( using my """" treated (soft) water)
anyway, I noticed in the " instruction DVD" they showed an optional SWG made for intex (their Krystal clear pump/filter systems) for about $150 us.
Is this a good thing for me to have ? or should I just stick to the BBB plan I was so successful with on the previous pool?

anyway, I know this isn't the choice pool of many owners and pro's out their, but I just didn't see spending $1900 on a pool that was way too small {12'} and didn't have installation included. this was the cheapest I could find, which I have learned cheap isn't always good. Maybe in 5 or so years I can afford the dream pool, and deck setup I really want, but for now, (after 3 days of correcting a 5" dif in level...) this is something for the preg wife and 9 y/o girl to enjoy.
anyway, curious about the swg, and any other suggestions reguarding filters. i.e. can I change this out to a sand filter ? (looks to have 1 1/2" threaded fittings)
also, the "Ben" test kit... not to sound really dumb here, but what are the advantages to this kit over the aqua pro kit I have now (with new reagents)?? I am curious to get one if it will help keep the chemistry right.

my water going in,
18'x 48" (aprox 6500 gal)

ph 8.1
fc 0
tc 0 *** due to water treatment systems, have added bleach in small quantity as water is being filled, using pucks as well, til cya can be added
obv, cya 0
ta 130 ppm
cal hard, 0
salt, < 150 ppm
tds, 429

anything I should change other than dropping ph a bit, and adding 20-30 ppm of cya ?

Thanks in advance for the advice,
love the sites, and pass them on to all I meet with a pool ...