This site is great.

[PoolDoc]

Your best choice for periodic testing is probably the Taylor K2006 -- links to Amazon below, but only order if the Amazon seller is "Amato Ind"; other sellers seem to mixup the K2005 (no FAS-DPD) & K2006. Regardless, you need kit that includes an FAS-DPD test, and a CYA test; 'goofy strips' are just not accurate enough.

Ben

[Watermom]

Glad the pool is clear and it appears that the DE filter was not the problem. Good. Do yourself a favor and order that good test kit. You won't be sorry you did. It will do everything you need a kit to do and it will make your pool maintenance much easier as well as make it a lot easier to clean up if you ever have a problem. Good luck.