Do DSB's need to be replaced once in a while?

[t5Nitro]

My tank goes through a constant algae battle. Either I need to perform large % water changes with constant scraping forever or is it possible the sand bed needs to be completely siphoned and replaced with new? It has been in there for about 3 years.

Filtration, light, and feeding is fine.

 

[Alex T.]

How deep is the sand bed?

 

[t5Nitro]

4-5" or so.

 

[Aquarist007]

Depending on how you have maintained the sand bed it might not need replacing.
You should be adding about 1/2 an inch each year with new argonite.
If you siphon this out now you could release alot of nitrates etc that make the algae worse