Having Diatom problem, can Someone help me?

+1 problem stems from the use of non RO water

 

In general, algae problems are usually caused by aquarium water with excess nutrients like phosphate, nitrates, silicates etc. In the long term you may have to examine how you care for your tank. There are some commercial dry foods also contain excess nutrients and other undesirable things like nitrates, phosphates etc so I strain/rinse my fresh/frozen foods before feeding my tank. You may want to consider feeding your fish less often. Also using RO/DI water and a high quality salt with little if any NO3, phosphates etc like Tropic Marin will really help too. Adding a phosphate remover, increasing flow in your tank, adjusting your tank's photo period or replacing old bulbs may help too

 

I added a small reactor + biopellets and some GFO in my canister. Lights out for 2 days and it died down. A change in filtration will help if and when you have the money. are you able to get RO from a LFS? they usually charge the max 1 dollar per gallon.