Phosphate head ache

[Beanie439]

Hi guys so having a issue with high phosphates which is causing green algae to cover glass daily and rocks

70 litre

Tank has been running about 2 months now

Here are the parameters

pH 8.2
Nitrate 10-15ppm
Nitrite 0ppm
Ammonia 0ppm
Salt 1.025
Phosphate 2ppm was off the scale on a saliferts test kit but upping my water changes seems to have brought it down

I have 2 clowns, 2 bangal cardinals and algae blenny with 6 astrea snails and 6 blue eyed hermits

 

[erzwire]

gfo reactor or toss in some chemipure

 

[Beanie439]

Also forgot to add that its using a external! Was thinking about maybe using some phosguard?