So I have been dealing with brown "algea" on my sand bed for almost a year now I have done blackouts now I cant cover my tank but I've kept the lights off for up to a week. I've run red slime remover nothing has worked. This tank has been up for about 3 years. My nitrates are between 40-50. Ph is 7.8. Salinity is 1.025 and that's all I can test for right now between my son just being born and having to take unpaid leave from work I'm a little strapped at the moment. I would like to get a uv filter when I can but is there anything natural I can try untill I'm able to get other things.