If you already have the HTH 6-way drop kit and really have to squeeze bucks, the K-1515 FAS-DPD add-on test for $19. will give you the same essential capability as the K-2006. The key tests of FC, CC, pH, CYA, plus TA and CH are how we address 99% of the problems people face here.

When I had my Intex, I used their filters which could be hosed down several times before being discarded. There were no others that fit at the time. I made my own vacuum-to-filter by forcing a 3/4" PVC double-female connector into the end of an 18' length of 1 1/4" vacuum hose and attaching to a vacuum head that could take both a 1.5 and 1 1/4" hose. I plugged it into the drain where it fit perfectly, and even with the weak pump, was able to fully vacuum it.

These days, I swear by the Pool Blaster, but they are a little pricey.