water and filter change

[rookie]

hello
in the past i didnt know how to properly care for my aquarium however now i know alot more and i am getting into a regular schedule for my water changes however my nitrates are still a little high after my water change yesterday. i just replaced my filter cartrage today however i just added 3 new tiger barbs for a total of 6. they have only been in the tank for about 30 mins but i dont want them to have too hard of a time ajusting to my aquarium. since my ph is low and my nitrates are a little high should i do another water change? and is there any thing i should know about changing the filter cartrage and doing water changes togeather.

p.s the water i am replacing with the ph is higher so im assuming over a little time this will fix my ph problem gradually

[waterboy12076]

I would do a 20% WC. Also, did you replace the whole filter cartridge? What filter? Did you put any of the old media in the filter with the new cartridge to help seed?

[rookie]

its a standard cheep filter from walmart. i dont know what media is im assuming that it is the stuff inside the filter but the filter i have you just take out a cartrige and put a new one in