I definitely have to do something. IDK if my test kit is just old and doesn't read correctly, but here are the parameters and values I just measured:
Nitrate: 0-5 ppm, Nitrite: 0 ppm, Ammonia: 0.5 ppm
Now, I used this same filter in the same tank full w/ 7 fish before and always had perfect levels. One thing I could do is put the jur and IT in my 40 breeder, but I would have to take my del out of the 40 so it wouldn't get eaten and put it in w/ the aro. I could replace the heaters w/ stealths so no heater burn (or make heater guards, but I am wary of glass heaters since my last one broke) and follow one of the suggestions for cutting down the current of the in-tank filter. Do you think that is a better idea? The aro eats well and doesn't act like there's anything wrong, that I can notice, but any ammonia scares me.