Started my fishless cycle on a 20 gal 8/27 with Dr. Tim’s ammonium, I put in too much. On 9/4 I finally got a nitrite reading of .25, ph 7.6, Nh3/4+ still >8, No3 0. Today is ph 6.5, NH3/ 4+ >8, No2 .5, No3 10. Do I do a water change and add more Dr Tim’s? Change water and put fish in? How big of a change should I do?