A walmart kit is NOT going to give you the test results you need to properly maintain your pool. In our collective experience here we have narrowed test kits down to three that are cost effective, easy to use, accurate, precise, and test the parameters that need testing.
If you want to listen to our collective experience and avoid a mistake in buying a test kit then you want to get either Taylor K-2006 (NOT the K-2005 or any other Taylor kit), the Leslie's Chlorine FAS-DPD Service Test Kit (NOT the DPD complete chlorine kit or any other Leslie's kit!) , and the TF Test Kit's TF100.
All three of these kits use the FAS-DPD chlorine testing method which is far superior to the DPD testing method in other kits. A walmart kit is going to use OTO testing (chlorine test turns yellow) and I suspect that is what you are using now. It will not test free chlorine which is what you need to be testing for the most part.
Here is a link to the pool school article on testkits and in that article (in the very first sentence) are links to the three kits we recommend. The Leslie's Kit is a rebranded Taylor kit, btw. IMHO the TF100 is a better 'bang for the buck"
A good test kit will save you a lot of money and headaches in the long run and is the best investment you can make in pool care. It doesn't matter how expensive or inexpensive your pool is, the water chemistry is the same. Also, the intex filters, even when upgraded, are undersized so keeping proper water balance is even more imortant!
