For water testing, liquid type tests are recommended. The test strips are not very accurate. You need tests for ammonia, nitrite, nitrate, pH and KH. Most of those are available in kits, but usually KH has to be purchased separately. There are several different brands available.
I'm a firm believer than you can't have too much filtration, so the more the better. The type is really whatever your preference is, and what works best with your situation, as long as you have enough.
Many here have bogs. Some have moving bed filters. Some have a combination of different types.
I have a large bead type filter filled with k-1 media and a shower filter with ceramic media and a filter pad on the top layer of ceramic. There are also filter pads in the skimmer. And I have over 4 times the recommended amount of filtration for my pond, just to be sure there is always enough so the water quality stays good.
What kind of filtration do you have now?