Sand out when backwash

[Jessie_e]

Hi, i just bought a intex sandfilter and filled it with sand as instructions say. When i preformed the first backwash a lot of the sand came out the waste line. Is this normal?
What can cause the sand exit the filter?

 

[zea3]

Hi, welcome to TFP! Some sand may come out the first time it is backwashed and rinsed. If you got sand in the stand pipe while filling the filter it could blow out the waste line during a backwash. Other possible causes are loose or damaged laterals, or a loose or damaged stand pipe.

 

[JamesW]

Also, an oversized pump can cause sand loss during backwash. I would recommend not exceeding 20 gpm per square ft of sand surface area.

What pump do you have (make, model and hp)?
How many sq ft is the filter?

 

[Jessie_e]

Hi thanks for the answers. I have an intex sandfilter. Intex Krystal Clear 1,200 GPH Sand Filter Pump - 17233338 - Overstock.com Shopping - The Best Prices on Intex Pumps, Filters Accessories

But the 0,4-0,8 mm sand seems to go right through it when backwashing and it never stops I gues the filter will be empty after the summer. The first backwash pumped out 1/8 of all sand.

 

[PAGirl]

What sand did you use? Brand and description.

 

[Jessie_e]

The sand is Swim and fun, 0,4-0,8mm