Where do I start??? I have never experienced a problem like this before and I've been doing this for years. Every day without fail,brown algae grows and thrives in my tank. I know many people will say this is a new tank issue and I'm very familiar with that but this is not the case. This is not my first tank nor is it a new tank so I'm really looking for some serious insight here. The tank is 75 gallons and has been up for a year since an overhaul but the tank is about 4 years old. In the first couple years it was set up, it was decently planted but low light and never had brown algae. About a year ago, I redesigned the tank. I removed the flourite sand I had and replaced it with Caribsea Sea Naturals Sunset Gold sand for freshwater which is supposed to be inert. I added three large manzanita pieces to the tank, still used my 2 eheim 2217's that are well aged, an aqueon quietflow 55/75 HOB which has a 400gph flow. I only added some crypts and java fern to the tank due to me wanting the tank to be just a low maintenance tank, not really planted like it was. The lights are just the Current Satellite Freshwater+ LEDs which are not really high in PAR and should be great for the basic plants like crypts and java fern. My tank was mainly for my angels and just has basic plants added to it. The tank is not really what I would consider a planted tank compared to my others. Anyway, fast forward to today... Within a week, my glass, driftwood, and sand will be covered in brown algae. It is crazy. The tank has had this brown algae problem for the last year. I gave it months after the redesign thinking a normal bloom would be possible but we are 1 year later and the brown algae is growing like I've never seen in a tank before. I've tried scrubbing the tank completely clean and doing tons of water changes, it still occurs. I've tried backing off water changes and it still occurs. I've recently went on a new idea and tried attacking silicates which I know most say the cause of brown algae is. I've added tons of Phosguard and even tried using GFO, swapping it out every couple days. The brown algae seems to stunt for a day or so, and then just explode with growth again ruining the look of my tank. My glass will be filthy within a week and most of my sand will be covered densely in it within a two weeks. I've tried everything I know at this point, this is not a new tank issue at all. No sources on the internet seem to have any idea as to what this could be from. The last thing I've recently thought of is the substrate. I did not have the problem with the black flourite sand. Could it be the Caribsea sand that is supposed to be inert? Could it be releasing silicate into the water like crazy causing brown algae to just constantly feed and grow? At this point in time, all of my crypts have lost their leaves and java ferns have suffered due to being covered in brown algae. My parameters as of today are: pH 7.2, Ammonia 0, Nitrite 0, Nitrate 5ppm, Phosphate .25ppm if any (it is hard to tell on the test. It looks like 0 but I'll say .25ppm just to play it safe and say worst case scenario), KH 2, temperature 79 degrees. Please someone help me from just giving up on this tank and throwing everything related to it in the trash. I've been in this hobby a long time but I'm baffled and lost. If I forgot any details or you have further questions, please ask but all help is appreciated from any seasoned experts out there. I'm tired of band-aid fixes and no logical explanation for it, please someone help save my sanity.