I just did a water change today, and after filling it back up the water has been very cloudy. The tank (40B) is fully cycled- I did a fishless cycle and have slowly increased ammonia to 4ppm and maintained that while toying with stocking ideas and letting plants grow a bit. I have well water, but use prime just as a precaution since I do get mineral deposits from the tap. I've been using Flourish and I have 2 AC Filters (one 30 one 70). I did a water change once before to reduce nitrates, and did again today because they were reeaaalllyy high. I'm hoping to get fish in about 2 weeks, so wanted to get that down. Last change, the water was cloudy but I was still cycling so I just assumed it was a bacterial bloom. I did rinse out filter media at that time and added polyfill. This change, I drained the tank as much as I could, but I did not rinse out the media. After filling back up, I noticed the water was cloudy and the filters were kicking out some cloudiness as well. I checked the filters and did a little rearranging- both sponges and polyfill were tinted a redish brown color. This is not surprising to me, as I have seen this before in my house. If I don't clean my spare toilet regularly, I get the same color mineral deposits in the bowl. The toilet tanks get an orangey buildup as well. I have a plastic automatic water thing for my cat that I had noticed was getting stained yellow, so I've been using filtered water for him to drink. I'm wondering if this cloudiness is bacteria that will settle in time, or if this is sediment buildup? It's been almost 8 hrs and while there is improvement, it's still very cloudy. I'm obviously getting some kind of sediment residue on my sponges. So far.. the rearranging I did was remove the polyfill from the AC30 and added a second sponge I had laying around, and the biomax on top. The AC 70 has a sponge, polyfill (both untouched today) and I added a small layer of lava rocks I had on hand under the biomax. I'm not sure how I feel about the polyfill... it's loose material and seems cumbersome.. the lava rocks are also to weigh that down. I'm wondering if adding purigen on top of the biomax will help with this, or if there is something else I should be doing?