Filter Problems After Sand Change

[pgde]

I have a Pentair Sand Dollar Sand Filter (SD35) for my 5,000 gallon above ground pool. Several weeks ago, I had a local company change the sand in the filter. Before I get into a discussion with them, I would like to have some opinions as to what the problem(s) is.

Ever since then I have been having the following problems:

• When I backwash, only clear water comes out of the backwash hose. Normally, when the pressure increases by 10 psi (from 10 to 20 psi), there is filtered stuff from the pool which is washed out of the filter.
• After backwashing, the psi is 10, however after about 2 hours or so of ‘filtering’ the psi increases to 20. There is no sand being expelled into the pool.
• I had an algae outbreak (sue to a health issue I couldn’t work on the pool). I shocked the pool, killed the green algae and the water is blue again. However, the water is cloudy (white cloud). I have tried clarifier with no success. This may be due to the filter not filtering correctly. Another possibility is a high calcium level. However, we live in the desert and our normal hose water is hard – high in calcium. Any suggestions?

I am concerned about the filter. Any opinions about what the problem is?

 

[Texas Splash]

A few things come to mind:
- Why did you change the sand to begin with earlier? Normally sand never goes bad or needs to be changed UNLESS you let a pool store product like floc or clarifier get to the sand; then it's ruined.
- Which brings me to the next concern; you added clarifier, did it get to the sand? If so, that sand is now bad.
- For the pressure increase and cloudiness, that indicates algae. It was green and now white/hazy, but it has not yet been completely removed. To kill algae and completely remove it all, you need to follow the SLAM Process completely until all 3 SLAM criteria are passed.
- For the odd backwash issue, make sure the techs connected the in & out hoses correctly to the filter multiport valve. Sometimes people get them backwards.