it depends. brown algae as in diatoms? is your tank newly setup? most new setup comes with the usual hosts of problems such as diatoms, cyanobacteria, etc. for my pico, I have not encountered this till date as I overdosed carbon, purigen and rowaphos. I am also producing wet skimates. I believe this is more beneficial to smaller tanks as it exports the nutrients slightly faster while reducing effects of evaporation on salinity.
diatoms grow better in high phosphate, silicate and nutrient environment. please do conduct testing for ammonia, nitrite and nitrate. if you need ammonia and nitrate testing but have no budget, I can loan you my kits. I cannot really comment on filter capacity as I do not know about your setup. Nutrient production is a very dynamic process and nutrient exportation (especially with skimmers) can also be dynamic. It would depend on your filtration setup, your livestock and the technique you used to introduce them (gradual stocking vs fast, massive stocking), your husbandry techniques and the feeding scheme you are using. Please do list more details in order for the bros/sis around here to help you better.