Do it yourself - easier that way. http://www.amazon.co.uk/gp/aw/d/B000255NCI/ref=mp_s_a_1_1?qid=1431081973&sr=8-1&pi=AC_SX200_QL40&keywords=test+kit+aquarium&dpPl=1&dpID=412p7AYrVtL&ref=plSrch
A planted tank massively helps with water quality but it's likely to be hard to establish if you already have fish in place. A good alternative is those plants that float around on the surface but you have to remember to scoop the extra ones (that grow from the originals) out so that your tank...