Cloudy water

hillyjd

Well-known member
Sep 25, 2009
123
Tucson AZ
Ever since I replaced my cartridge filter with a Hayward sand filter (about a year ago), the pool water has been very cloudy. It was ok last summer and I was hoping it would clear up over time, but it has not. I religiously check the pool chemicals, and everything seems normal except the calcium is high. A couple of weeks ago I decided to get serious about this, so I measured the hardness in the pool and it was at 380. I measured the hardness at the spigot where the auto filler taps in, and the hardness was zero. Then I back washed the sand filter for five minutes (Hayward recommends 2 minutes) which dropped the water leverl about 3-4 inches. Let the pool fill up and there is very little difference (if any) in clarity. The hardness two days ago was at 370. Any suggestions?
 

frustratedpoolmom

TFP Expert
LifeTime Supporter
In The Industry
May 20, 2007
12,250
Key West, FL
Can you post a full set of results?
Have you tried anything like DE in the sand or a clarifier?
How often do you run the filter?
Do you see any air bubbles in your pump basket?
 

hillyjd

Well-known member
Sep 25, 2009
123
Tucson AZ
I should have included my latest chemistry

PH = 7.7
TC = 5.0
TA = 75
CH = 370
CYA = 30
Salt = 3300

- - - Updated - - -

Just posted
Have not tried DE in the sand or a clarifier
Filter runs 12 hours/day
No air bubbles in the pump basket
 

frustratedpoolmom

TFP Expert
LifeTime Supporter
In The Industry
May 20, 2007
12,250
Key West, FL
Ok, I was wondering if the cause could be a combo of high TA/PH/CH and aeration.

Try the DE. It may be something you need to do routinely. Are you saying "cloudy" cuz you're used to the pristine clarity of a cartridge? Have you done an OCLT to see if your FC is holding overnight? Your SWG needs to be off when you do this...
 

hillyjd

Well-known member
Sep 25, 2009
123
Tucson AZ
I can tell you that the pH has routinely been a challenge ever since I installed the SWG. Usually requires muratic acid every couple of days, but I was doing that before the sand filter went in. Ph seems to go higher faster ever since I installed the sand filter, but I try to stay on top of it. I do run the water feature pump 16 hours a day, but I've been doing that forever and never had a problem before. I am used to VERY clear water - but this is VERY cloudy. Water feels great and we have been swimming in it. I wil do the OCLT tonight and report back in the morning.
 

hillyjd

Well-known member
Sep 25, 2009
123
Tucson AZ
SWG has been off for a few hours. Just remeasured everything.

FC = 5.5
PH = 7.8
TA = 60
CH = 370
CYA = 20
Salt = 3200

Will recheck FC in the morning and see where we're at. Thanks for the quick responses.
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
Arizona gets find dust/sand and sand filters have a harder time with the smaller particle size compared to cartridge filters. You should definitely try the DE suggestion.
 

hillyjd

Well-known member
Sep 25, 2009
123
Tucson AZ
FC was the same this morning as it was last night, so that's a good thing. I'll pick up some DE this weekend. Do I just open the filter top and add some in like the sand? Any idea how much DE to use?
 

hillyjd

Well-known member
Sep 25, 2009
123
Tucson AZ
The article says to add the DE to the skimmer. Are they talking about the pool skimmer basket or opening up the sand filter and adding the DE directly into it.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,870
San Dimas, CA (LA County)
The article says to add the DE to the skimmer. Are they talking about the pool skimmer basket or opening up the sand filter and adding the DE directly into it.
Just pour it in the pool skimmer. It will mix up and get sucked away and form a fine layer on top of the sand; envision setting a window screen on top of a barbecue grate. Careful not to set the bag too close to the edge of the pool. That could get ugly....

Watch the filter pressure. If you have a lot of dust, it will load up pretty fast, like a couple hours. Then just backwash like normal and add another cup or two.
 

hillyjd

Well-known member
Sep 25, 2009
123
Tucson AZ
After a week with adding DE to the pool, I thought there was some improvment in the water clarity, but on Sat, after my wife said she didn't think it looked any better, I decided to add some clarifier. Had some old stuff in the garage, but it looked ok so I added the recommended amount. Three hours later the pool is worse than ever!! Can't see the bottom at all, even in the shallow end. Could the clarifier have the opposite effect? So back to square one. Have been running the filter 24/7 the last two days with no improvement. Have back washed it twice and added DE each time. Just measured my chemicals:

FC = 8.5 (not unexpected with the SWG running all the time)
PH = 7.7
TA = 40
CH = 340
CYA = 15
Salt = 3100

Couple of things on the chemistry. TA has dropped from 70 to 40 over the past two weeks while adding the DE. CH has dropped from 380 to 340. Do I think about adding some baking soda to bring up the TA? When I've tried that in the past, Ilose control of the PH. Any suggestions would be appreciated.
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
Overdosing with a clarifier can have the water become more cloudy. Also if a clarifier is used at the same time as Polyquat algicide, you create a precipitated mess. This is one reason we normally do not recommend using a clarifier. In the worst case if one is used, there are only two that are recommended.

I'm not sure why adding the DE would drop the TA. The TA would normally drop only from acid addition.

It seems to me that your circulation/filtration is having a problem somewhere. Especially after adding DE to the sand filter and not seeing improvement. Are you sure there isn't significant channeling in the sand filter or that water is bypassing the filter somehow or that your circulation in the pool is poor?
 

hillyjd

Well-known member
Sep 25, 2009
123
Tucson AZ
I did not use any algicide, so I don't think that's it. I did use the recommended dosage of clarifier, but I'm sure it was some cheap brand I found at Wal-Mart. If I ever go back to a clarifier, what brand do you recommend?

Even before I put the sand filter in last year, I have always had to use a lot of muratic acid to keep the pH in check. I usually add 32 oz every 2-3 days, just to keep the pH around 7.7. That's why I was wondering if I should drive the pH even lower and then try some baking soda.

As for circulation, not sure how to evaluate that. I installed the sand filter myself, but it was a pretty straightforward installation. I can tell you that the DE by itself seems to work. I say that because I can see the rise in filter pressure after I add DE. For example, I back washed the system yesterday morning and this morning the pressure is up by about 2.5 psi. I'll probably have to flush it again tonight when I get home. Before I started using DE, I would never have seen a pressure rise like that in a month. Also, whenever I back flush, the water is very dirty for the first 30 seconds or so.

Anyway, thanks for the response.
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
You should never have to use a clarifier except in the rarest of cases, such as when one gets a colloid in the water (think milk) that cannot be caught by any filter. In that case, GLB Clear Blue or Bioguard Polysheen Blue would be recommended clarifiers, but again they are hardly ever needed. Think of it this way: if the particles are big enough to get caught in the filter, then it just takes time for multiple turnovers to "catch" such particles. A clarifier won't make that happen any faster -- you still need to get the particles to the filter via circulation/filtration.

If you are adding acid to keep the pH down, then you do not generally want to raise the TA level because a higher TA just increases the rate of pH rise from carbon dioxide outgassing. TA is a measure of the over-carbonation of the pool.
 

hillyjd

Well-known member
Sep 25, 2009
123
Tucson AZ
Filter was up 5 psi when I got home from work last night, so I back flushed and added 1.5 cups of DE and ran the pump all night. Pressure up 5 psi this morning, so I repeated the process. Maybe a little bit clearer this morning. Hard to tell. Still VERY cloudy. Just takes time I guess.

I read the TFP article about SWG chemistry for the first time yesterday. Very surprised to see that it recommended keeping the CYA about 70 with SWG in order to keep the pH in line. I had always associated CYA with Chlorine stability, not pH. My CYA has been very low this year, between 10 and 20, which would explain why I need so much acid. So I added a bunch of CYA last night and this morning the pH was down from 7.8 to 7.2. Will measure again tonight and see where I'm at. Hopefully less muratic acid in my future as well.

Thanks again for all your help.