DE Filter Problems

DE Filters are usually pretty easy to troubleshoot.  The filter media does not “go bad” since it is replaced every time the filter is backwashed.  The filter elements themselves can go bad, but when this happens, the problem is generally very easy to track down and repair.  

Problem:  Bad Grids or other Internals

Symptom:  DE Filter Powder Returning to the Pool

If one of the parts inside the DE filter goes bad, it is immediately obvious because DE will be returning to the pool.  Always keep an eye on the filter returns after recharging the filter just to make sure nothing is coming back to the pool.

There are several problem areas that can cause DE to return to the pool:

Torn Filter Grids – these are usually pretty easy to spot when washing down the filter grids.  Holes can develop anywhere in the fabric of the grid.  Don’t forget to look at the
very end of the grid.  Many times a hole will develop on the bottom of the “tube” of the grid. 

Broken Manifold – a cracked manifold will cause a large amount of DE to return to the pool

Broken/Missing Air Relief Strainer – if the air relief strainer is broken or missing, it will allow DE back into the pool.  

Broken Filter Necks – this can be a tough problem to detect.  If the neck of the grid can squeeze together easily, then it will not fit snugly into the manifold and will cause DE to
bypass, especially right after the filter is started up.

Bad Backwash Valve – if the DE is bypassing the filter, it may be caused by problems inside the valve.  Disassemble and inspect the valve.

Problem:  Oversized Pump or Failure to Backwash

Symptom:  Crushed Grids or Manifold

It is not unusual to find grids or manifolds that have been crushed by high pressure inside the filter.  Today’s high head pumps have extra power to spare and can quickly damage a filter.  The way to avoid this is to be sure to backwash at regular intervals and not put it off.  It is also important to properly size the pump to the filter.  The natural tendency is to install pumps that are larger than what is really necessary.  If the pool really needs a 2.0 hp pump or larger, consider installing a StaRite filter because its grids are less likely to be crushed by high pressure.