fr499y wrote: ↑Thu May 02, 2024 12:53 pm cyanobacteria isn't an algae but bacteria. You can get stuff that treats it but It will keep coming back unless you get to the bottom of the cause.
What is the filter in question and how big is the tank? Its not unusual for shops to sell a filter and say 'Its more than enough for that size tank' when in reality, its not.
How often do you do a water change and how much are you changing at a time?
What fish are you keeping?
Do you have any live plants in the tank?
Tank is 155l and the filter is 400….this one… https://amzn.eu/d/dwOH1pK
There was plants in there at one point but as i havent had the time ive left it go and all the plants are gone, only had two fish, one cat fish and a shrimp.
Dont do water changes that often due to work commitments but thats died down i have the time again so will be doing fortnighly again, roughly 20/30l at a time.
Thanks