I posted a similar question. Just found this post. I cycled with dr. Tim's. everything went perfect.....but got a bacteria bloom. After 7 days with no ammonia, nitrites, under 20 nitrates...I added purigen to a 20g filter (in addition to the 60g filter with sponge, carbon, and biobag) in my 55g tank. Bacteria bloom was gone in 24 hours. But, my nitrates are now under 5, and I can't use the black water extract my angelfish love. Im not even sure when to do a water change, cause my water is clear....and nitrates are next to nothing! is the purigen plus carbon working TOO well? The purigen has been in for 4 days. Tank running for a month. I'm afraid of a mini-cycle if I remove purigen and carbon. But my angels are pale and clamping in the harder water (theres also driftwood in the tank that no longer helps, because of the purigen). my tabk is not overstocked, but these fish have never felt more than .25 nitrites for under 24 hours thanks to the dr tim. a mini may kill them. is there anything that will soften the water safely if i leave the purigen in? Any thoughts?