So I think I may have caused my tank to cycle again due to my water parameter readings. I have 2 20g long tanks, one planted and one unplanted. I just recently added an overflow system to the setup, which overflows water from the unplanted tank down to the planted tank and from the planted tank down to a trickle filter which returns the water to the unplanted tank. Before I added this setup, both tanks were completely separate with their own filters. The readings before adding overflow- Unplanted pH 7.6 Ammonia .25 Nitrite 2.0 Nitrate 0 Planted pH 6.6 Ammonia 0 Nitrite 0 Nitrate .25 Readings after overflow- (around 24 hours later) Unplanted pH 7.6 Ammonia .25 Nitrite 0 (Why did this drop to 0?) Nitrate 0 Planted pH 7.6 Ammonia 0 (unsure why this is not the same as the unplanted tank since I would assume most of the water would have evened out) Nitrite 0 Nitrate 0 The planted tank has injected co2 which is why the pH level was much lower than the unplanted before adding the overflow. Also the unplanted tank was setup about 2 weeks ago, so it was not finished cycling yet. I made an assumption that by allowing the planted tank (which was already cycled) to combine with the unplanted that it would cause the unplanted to cycle faster. Did I accidently f-up and cause both my tanks to crash? Why did both of the readings drop to 0 when before I had some nitrites and ammonia? Is there a possibility that I will see some of the readings spike? And why did the pH increase to 7.6 in both tanks instead of balancing inbetween at around 7.1 ? Also after adding the overflow, I had an outbreak of green algae all over the glass of the planted tank.... is this due to the sudden increase in water volume? I'm hoping I didn't mess up because I have a longfin ram in one of the tanks and he was doing fine before I added the overflow, but now his dorsal and pelvic fins are clamped together... He also seems to hover just under the surface of the water, when before he used to hide around the caves near the bottom. From what I understand Rams are extremely sensitive to water parameters so I think he may be in shock from having the water parameters changed. If my tank has to cycle again I'm not sure he would do very well... NOTE: I almost forgot, right after getting the overflows hooked up and working I did a 25% water change to both the tanks.