I have an established 60P, setup around September of last year. The basics are, it's about 18 gallons, has an Eheim 2215, no heater, high light, CO2 injected. The reason I don't run a heater is I do not need to.
Lately, I have had extremely cloudy water. I get about 1-1.5 weeks of cloudy water, then it clears up, then it gets cloudy again.
First things first, about a few months ago, I put in Guppies, they have been breeding. Part of me thinks that it's a constant increase of bio load, though, it didn't happen when they started breeding, maybe once the first babies got big. It may be as simple as that.
The other major change is I went from low tech to high tech. Around the same time this started happening, I increased my light and started injecting CO2. I have never had issues doing this, it is strangely about the same time it happened though. I also add ferts, while low tech, I really didn't use any.
My water parameters are:
Nitrate: lost the card, low, zero to 5PPM and I do dose it so it is not concerning if it's over zero.
I started out with 3 male guppies, 4 female. Since then, 3 are getting close to adult hood. All others are still far from being adults. I would guess I have 15-25 fry, hard to see, but still very small. I would doubt that increase in bio load is significant enough to cause a cycle, much less give me constant cycles but I could be wrong. I know I have added more adults in shorter periods of time with no cycle, plus this tank has been up for close to a year now.
I don't know why or how going higher light and injecting CO2 could make this happen either, the timing of it just seems a bit odd.
Lastly, everything in my tank is healthy, both plants and fish. I even switched to RO water after two instances of cloudy water to rule out my tap water. It did nothing positive or negative to the cloudy water, I have had two more instances of cloudy water afterwards.
I have not had a single death, my fish actually look even healthier after switching to RO but at no point did they look unhealthy, or did I have any concerns.
I can hook up a second filter, add a UV, even a heater if need be, I know the UV will likely clear it up no issue. I don't like the UV's effect on flow, one reason I took it out. When I did have it plumbed in, I don't recall ever using it, on this particular tank.
Anyway, in all the years in this hobby, never had anything like this happen, it's very confusing to me. My tank is so cloudy right now, I can't see the back plants, it's pretty significant. Water changes only seem to make it cloudy for longer, the water will clear for a day or two but then get worse than it was.
Any help is appreciated, I would like getting down to the root cause, rather than just turning the UV on and hoping it doesn't come back when I turn it off, I just have no idea what's going on, especially given the fact I see no evidence of a cycle, much less a significant one with my water testing.
I can only get a picture on my phone right now. The water may look slighly green but it's not, back glass is cracked and takes bad pics. Definitely white cloudy, not green at all.