Getting rid of brown algae/diatoms HELP?

[P87]

Am suffering with a brown algae on my 3D background and rocks(fake) Aquadecor

I understand there coming from my water possibly but how do I take them am running seachem purigen in my sump in a bag it’s Malawi peacock and hap tank in my salt water I run phosphate remover but won’t this die much quicker with tap water we’re am not using rodi water in my cichlid tank has I change around 300l a week out of it if not more some times I take rocks out and clean it of and brush it off the background but it’s comes back after a few days is there a other way to combat this in freshwater set ups all the help is appreciated
Thanks

 

[Rocksor]

I get that too in my main tank in the house. Purigen doesn't work and phosphate remover has no effect. Not much you can do about it if there's light directly above the tank under the canopy and if the room that it's in gets ambient sunlight (sun beam doesn't have to hit the tank). My garage tank doesn't get diatoms, and only has a regular lamp bulb more than 3 feet above tank and it's pretty much pitch black in the tank for 17 hours. Nutrients wasn't also the culprit since my garage tank had a south american lungfish that produced more waste in the tank from food, etc. than in my main tank. So the only difference I could see between the 2 tanks was the amount of sunlight in the room. Garage tank had zero possible sunlight unless I opened the garage door, and even then it was briefly opened.

 

[P87]

I get that too in my main tank in the house. Purigen doesn't work and phosphate remover has no effect. Not much you can do about it if there's light directly above the tank under the canopy and if the room that it's in gets ambient sunlight (sun beam doesn't have to hit the tank). My garage tank doesn't get diatoms, and only has a regular lamp bulb more than 3 feet above tank and it's pretty much pitch black in the tank for 17 hours. Nutrients wasn't also the culprit since my garage tank had a south american lungfish that produced more waste in the tank from food, etc. than in my main tank. So the only difference I could see between the 2 tanks was the amount of sunlight in the room. Garage tank had zero possible sunlight unless I opened the garage door, and even then it was briefly opened.

I have two lights running above the tank for maybe 7/8hours a day blues for a bit then to white light am running led lights over it the room gets natural light but it dose not hit the tank directly tho I don’t ever get it on my sand either

 

[Rocksor]

I have two lights running above the tank for maybe 7/8hours a day blues for a bit then to white light am running led lights over it the room gets natural light but it dose not hit the tank directly tho I don’t ever get it on my sand either

The first thing to try is no light for 2 weeks. No blue no white light

I didn't get the diatoms on my sand either. I have bedroom spotlights over the main tank that is only on for about 1-2 hours. No need for anymore because the room is pretty well lit through ambient room light during the day. My main tank does not get hit by sunlight. The diatoms are always on the side panels of the tank.

If this room was pitch black with no sunlight entering the room at all, and with only the spotlights, I doubt my main tank will have diatoms just like my garage tank does not have diatoms.

 

[P87]

Will give this a go