I recently bought a house that has a pool and the filter was broken so we bought a new one. I don't know how long the sand has been in the old filter but it looks good I think? Here is a picture for reference. Sand - Album on Imgur I already took it out of the old filter.
Should I reuse the sand from our old sand filter?
- Thread starter sambot
- Start date
As long as you can easily run your hands through it, it should be fine to use. Cover the center standpipe so you don't accidently get sand in it and make sure you backwash and rinse well before setting it to filter.
Seems like most people say that sand doesn't really go bad, so I am going to use your advice and reuse it. 
Also the fact that I don't know what to do with 300lbs of old sand and my laziness to get new sand might have played a part XD
Also the fact that I don't know what to do with 300lbs of old sand and my laziness to get new sand might have played a part XDI think it would be fine. However, filter sand has rough edges which is how it is different from regular sand pumped straight from the river. Filter sand is fractured or crushed to create the sharp edges that makes it filter well. Sand pumped straight from the river like Masonry , Gunite or Concrete sand is round from tumbling in the river current. That being said I am sure filter sand starts to become round at some point in its life span from being tumbled in the sand filter. I think it would take a long time, but pretty sure it happens like that.
Just how much tumbling do you think is happening to 300 pounds of sand? It sits mostly stationary with only the top layer maybe getting jostled around a bit.
Here is a thread where pictures were posted of used filter sand and "fresh" sand as observed under a microscope. There was no real difference between the two.
Old filter sand - up close!
Old filter sand - up close!