Whats this?

[Alanh087]

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

[fr499y]

I'd start with giving the filter media a swish in old tank water as those APS filters are nowhere near the advertised LPH, you'd want the next one up for a 155L tank really.

you want to be doing 30L a week as depending on the catfish species, they tend to be pretty messy fish.

[Alanh087]

I'd start with giving the filter media a swish in old tank water as those APS filters are nowhere near the advertised LPH, you'd want the next one up for a 155L tank really.

you want to be doing 30L a week as depending on the catfish species, they tend to be pretty messy fish.

If i bought this filter would that solve the flow issues at the bottom of the tank?

https://amzn.eu/d/gCBlEUY

[fr499y]

it might do, but you'll be better off with a small powerhead as you can move them around if you have a dead spot.
Like This the small one will do the job.

[Alanh087]

it might do, but you'll be better off with a small powerhead as you can move them around if you have a dead spot.
Like This the small one will do the job.

Great thanks il buy one of them, looking at the info guess the small one would be ok as that does up to 60g of water…

[fr499y]

Certainly will be enough.