@UffnerReef As mentioned above, the bacteria from your DT water probably initiated a bacterial bloom which made the water turn cloudy and robbed O2 from the water. Nitrifying bacteria in the water is fine, but you must have a way of harnessing it. This is why it is so important to utilize a filter in QT (canister or HOB) which contains bio-media capable of housing nitrifying bacteria. You want that bacteria in your filter, where it can help break down ammonia; not free floating around in the water with nowhere to go and where it can cause problems. For those who opt not to use biological filtration in QT, I suggest using freshly mixed SW instead of DT water as the former contains little to no bacteria. @shoelaceike IME; fish are not overly sensitive to pH swings UNLESS going into a lower pH. Bag water will have low pH, so they will be just fine going into the higher pH your QT should afford them. Test beforehand to be sure. It should be 7.8 - 8.3. @DeniseAndy You are more than welcome to transpose or link your protocols here, in my "How to QT" thread or even start your own thread with them. More info the better! My ways are not the only ways.