Sand Filter rejuvenation

Noobpool

Well-known member
Apr 5, 2017
64
Cullman , Al
#1
Ok y'all I have read and watched the videos on cleaning sand filters I have followed that process and think I am about done with cleaning and now 9n the adding sand portion. Can someone chime in on whether or not I am pretty well done? My sand was mostly gone. Filter states sand to within 6 inches of the top of the standpipe and I was a solid 18 to 20 inches (dang near empty) below top of standpipe. Please advise
 

JVTrain

TFP Expert
Feb 3, 2014
5,080
Central Minnesota
#2
That looks pretty clear. I'd say you're good to go. Dump in some new sand and fill to recommended height. Make sure you cover the top of the standpipe with a plastic bag with rubber band when dumping in new sand or whatever you can devise to cover it so sand doesn't get into it.
 

Noobpool

Well-known member
Apr 5, 2017
64
Cullman , Al
#6
Pressure guage has not worked since I bought the house. I will be installing a new one today along with an elbow (maybe I failed to calculate clearance room)
 

Noobpool

Well-known member
Apr 5, 2017
64
Cullman , Al
#7
Ok got it all buttoned back up new guage runs about 8psi. From pool school I gather that I can add DE to around 10 psi via main skimmer and backwash around 10 over normal which is 20ish psi correct?
 

Noobpool

Well-known member
Apr 5, 2017
64
Cullman , Al
#8
This is where I have been for a week passed oclt twice in a row. Had some rain and cooler weather though. Weird little bubbles on surface since I cleaned and topped off the sand filter (added 2 full bags and a partial, around 120lbs or so.)
 

JVTrain

TFP Expert
Feb 3, 2014
5,080
Central Minnesota
#9
You should backwash at about 25% over normal so if your normal is 10 psi with the DE, I'd backwash at 13.

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This is where I have been for a week passed oclt twice in a row. Had some rain and cooler weather though. Weird little bubbles on surface since I cleaned and topped off the sand filter (added 2 full bags and a partial, around 120lbs or so.)
What specific sand did you use? #20 pool sand?
 

JVTrain

TFP Expert
Feb 3, 2014
5,080
Central Minnesota
#12
If the brand happens to not be rinsed very well before packaging, that could be lots of dust in the sand. If so, should filter out in a couple days. Did it seem dusty when adding?

Sent from mobile device. Beware of brevity and grammar errors!
 

Noobpool

Well-known member
Apr 5, 2017
64
Cullman , Al
#13
Not at all. Very rough not smooth like beach sand but no dust or powder accumulation . My pool has been cloudy for weeks. I have been slamming for 9 days now and redid the filter in the hopes it would clear. My numbers are all good (ph is high) but otherwise steady and stable
 

JVTrain

TFP Expert
Feb 3, 2014
5,080
Central Minnesota
#14
Keep in mind, the pH test is invalid (will read very high) whenever your FC is above 10 ppm. So ignore it until you're done with the SLAM. This is why it is recommended to lower pH to 7.2 before starting a SLAM as pH cannot be tested until complete or FC drops to <10. I would say that you're waiting on your filtration to get all the fine particles out at this point. Keep that pump on, keep brushing eventually you'll get all that fine sediment out. The DE should help speed the process. Your CH is borderline low, which typically does not matter in a vinyl pool. Low CH can contribute to foaming/bubbles but I wouldn't worry about it at this point. Likely just need some patience, which I know is tough with the SLAM going for 10 days or so now, but for some of that, you had a filter with very low filtration capacity.
 

Noobpool

Well-known member
Apr 5, 2017
64
Cullman , Al
#15
I have ceased with the slam. 3 days running I passed oclt. I have been checking FC and CC in the morning and afternoon since I quit maintaining slam (yesterday afternoon) my CC test barely turns pink now. I still have cloudy pool water though. I will get in tonight and brush and vacuum again. My wife has scheduled a pool party Saturday for her co-workers. What is the general consensus of flocculant? I was thinking that if the filter does not clear the pool by Thursday I would floc Friday and vacuum to waste Saturday morning before anyone arrives
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
20,327
San Dimas, CA (LA County)
#16
I have ceased with the slam. 3 days running I passed oclt. I have been checking FC and CC in the morning and afternoon since I quit maintaining slam (yesterday afternoon) my CC test barely turns pink now. I still have cloudy pool water though. I will get in tonight and brush and vacuum again. My wife has scheduled a pool party Saturday for her co-workers. What is the general consensus of flocculant? I was thinking that if the filter does not clear the pool by Thursday I would floc Friday and vacuum to waste Saturday morning before anyone arrives
Try the DE in the sand filter trick first. It doesn't take much, only a cup or two, so see if you can't beg or buy some from a neighbor or some pool service guy.
 

JVTrain

TFP Expert
Feb 3, 2014
5,080
Central Minnesota
#18
1 psi is stated in the article. 1/4 cup at a time, wait several minutes after each addition, check your filter pressure. Repeat until 1 psi increase. After adding your full amount of DE, check filter pressure as frequently as practical as when dealing with lots of algae or suspended material, the pressure could rise rapidly.
 

Rollercoastr

Gold Supporter
May 18, 2016
804
West Bloomfield, MI
#19
I do 1 psi. You'll also need to time this addition so that you can be nearby to monitor pressure. It will have a cumulative effect and can spike the pressure much more quickly than you're used to.

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fast typist!
 

Noobpool

Well-known member
Apr 5, 2017
64
Cullman , Al
#20
Ok since I cleaned and topped it off and added a functional gauge the pump averages 8psi and daily builds to 12ish so I have been back washing daily as well
Edit: I assume the cloudy particles is the reason for the increased pressure. Since I am not getting dirt or debris when I backwash on both backwashes