Something starting growing wildly in your tank? That's called a 'bloom.' You can have blooms of phytoplankton, in which your water turns green [not good: oxygen depletion at night!] or blooms of flatworms [not good, and worse when they die off en masse]; or blooms of feather dusters, or bristleworms, or mushrooms, or hair algae, or macroalgae, or zoas, etc., etc.
The thing to fix in memory is this: If there's a bloom, what's feeding it?
Algaes---look at phosphate levels: phosphate is plant fertilizer.
Bristleworms---overfeeding.
Flatworms---you imported one and they're finding stuff to eat.
Mushrooms....your water has a lot of food in it and they love the conditions.
To slow down or reverse a 'bloom' is not always easy, but the basics are: don't import something to eat it, if you can at all help it. Try to take away what IT'S eating, and that will solve your problem.
Remember that, when you get too much of a good thing or way much of a bad thing. Remove or reduce what ITS eating.
HTH.
The thing to fix in memory is this: If there's a bloom, what's feeding it?
Algaes---look at phosphate levels: phosphate is plant fertilizer.
Bristleworms---overfeeding.
Flatworms---you imported one and they're finding stuff to eat.
Mushrooms....your water has a lot of food in it and they love the conditions.
To slow down or reverse a 'bloom' is not always easy, but the basics are: don't import something to eat it, if you can at all help it. Try to take away what IT'S eating, and that will solve your problem.
Remember that, when you get too much of a good thing or way much of a bad thing. Remove or reduce what ITS eating.
HTH.