Problem with water being cloudy/murky.

Hi,

First time poster, but I have lurked around this and the TFP forum before.

First, a little intro. I live in SE Texas, near the coast, about an hour from Houston. I have an inground pool, approx, 18,000 gallons. Gunite/plaster. Had the plaster re-done last year. My filter is a sand filter, my pump is a 1-HP pentair whisperflo. I installed the pump/filter myself around 2006, before that I had a DE filter.

I bought this house second hand, the pool was originally installed in '88 or '89. Through the years I have done my fair share or more of upkeep..actually way more than I would like.

The big problem I have been having this year is that the water just stays cloudy and murky. I have tested the water myself several times, the pH and Alk. are all within the normal ranges, as is the hardness. It seems that the water will try to clear up a little, and then go right back to being cloudy. I'm using tons of chlorine and backwashing the filter when it needs it (going by the discharge gauge).

I have several thougths on the causes. One thing I'm suspecting is that my filter is not working correctly either due to internal problems or maybe the sand needs to be changed. I changed the sand once before a few years ago but it didn't really help. I have heard that the selection valves get messed up and let the water bypass the filter, or at least a side stream.

Second thought is that it's algae that I'm not clearing all the way out. Normally when the pool gets infested with algae it turns green and you can see it on the walls /surfaces. This really looks more murky than anything else.

Other thoughts are that my chemistry is not right and my tests are wrong. I'm going to take a sample to have checked this week, but other than that any tips or anything would be appreciated.

It's really kind of hard to tell much without water testing results. Post those when you get them and we'll take a look. Consider getting yourself a good test kit instead of relying on a pool store to test for you. We like the Taylor K-2006 or 2006C which is the same kit with larger quantities of some of the reagents. Click on the Amazon link in my signature. If you order through that link, the Pool Forum makes a little money on the sale which helps keep the forum online. Only buy if the seller is Amato Industries as some other sellers are substituting the K-2005 which you do NOT want.

It isn't necessary to change the sand. I'm on my 11th season with mine and some people are going much longer with theirs than I am.

Re-post with readings and we'll go from there. Welcome to the forum!

Thanks for your quick reply. I do test my own water, and right now the pH is within range, as is the hardness/alk. I don't have the numbers sitting in front of me as I'm away at the moment but I will have them tomorrow. The only reason I'm taking them to the pool place is to see if they get anything different. They always try to sell me some stuff I don't need but I never fall for their tactics.

I'm really at wits end with this pool. Last year after having the plaster and skimmers fixed it was a dream for a few months. Very simple and easy maintenance, chlorine stayed good, everything was great until the end of the season when I started having problems. Now i'm back to my nightmare. I didn't think that the sand went bad but perahps I'm not flushing it throughly or maybe I need to run my pump longer? Right now I'm running it 12 hrs per day with an in-line chlorinator but the water never clears, even when I keep the chlorine levels high for days.

Also I forgot to add that I am considering going back to a DE style filter. I have heard that they work much better, and now that my skimmers are functioning properly I would be able to charge it correctly ( my skimmers were non-functional until last year. Long story). Any thoughts on this?

Tell us how you are testing, and what the numbers are. (If you've hung around here & TFP, you know we're probably going to tell you to get another kit, unless you have one of my old kits, a Taylor K2006 or the TFP kit!)

Tell me what make / model of filter you have.

I'm just guessing, without that info, but my guess is you've installed a filter that's too small, and have blown most of the sand out, when backwashing.

(BTW, Lisa, sand normally is NOT present in backwash. When it is, the sand is not properly graded OR the filter is too small. Of course, that describes more than 3/4 of pools with sand filters, so I guess it is "normal" in the statistical sense. But it's not 'right'!)

Ben

When you post the numbers, please include the free and total chlorine readings. (just to rule out an algae issue)

You can also supplement your sand filter with ~ 1/2 cup of DE if the cloudiness is being caused by something too small for the sand to catch.

Thanks for your replies everyone. Ok, had the water tested (professionally today), and the results pretty much match up with my home tests. Here are the results:

FC 2.1 ppm
TC 2.1 ppm
Combined Chlorine 0.0
pH 7.6
Hardness 250 ppm
Alkanity 67
CYA 10 ppm
Copper 0
Iron 0
TDS N/A

I was using a Taylor kit for chlorine and pH, and then a different kit for the Alk and hardness (blue box kit, don't know the brand).

I have a Tagelus 60D sand filter, rated for about 60 gpm, my pump does somewhere around 30 gpm. I installed the pump and filter myself.

Quote:

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Originally Posted by PoolDoc

Tell us how you are testing, and what the numbers are. (If you've hung around here & TFP, you know we're probably going to tell you to get another kit, unless you have one of my old kits, a Taylor K2006 or the TFP kit!)

Tell me what make / model of filter you have.

I'm just guessing, without that info, but my guess is you've installed a filter that's too small, and have blown most of the sand out, when backwashing.

(BTW, Lisa, sand normally is NOT present in backwash. When it is, the sand is not properly graded OR the filter is too small. Of course, that describes more than 3/4 of pools with sand filters, so I guess it is "normal" in the statistical sense. But it's not 'right'!)

Ben

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OK, now we see that my alk and CYA are a little low, but not super low (except CYA). I will work on those two tomorrow. I don't think I have lost my sand, but I have plans to take the sand filter apart tomorrow. The dP on the sand filter rises generally over time, as you would expect. I backwash normally ever 1-2 weeks, and you can tell if the filter is getting plugged because not enough water is coming through the pool return jets.

Thanks for your advice and input.

OK, I ordered the Taylor K2006 kit. Today I'm adding baking soda and CYA to get those numbers up a little, and then I'm taking apart the sand filter.

Keep in mind that if you add the CYA through the skimmer, and then take the filter apart, you're going to lose your CYA...it takes several days for it to sit in the filter and dissolve. If you added it via sock, then you should be okay.

I wouldn't worry about the TA for now--get the filter working, get chlorine in the pool, and once it clears up you can tweak the rest of the numbers.

Janet

OK, added the baking soda and some CYA. Also I finally took the filter apart, everything looked pretty normal with the filter and the sand. I went ahead and changed the sand out as I was out of ideas. I noticed when putting in the new sand that the level was higher, so I definitely think that pooldoc was on to something with the fact that I've lost some sand. The pool water was immediately clearer but not totally clear. I think as the filter operates normally the water will get better every day.

What are your suggestions on the loss of the sand? I was thinking that I could add some to the skimmer (like how you add DE) every so often....or install a throttle valve when backwashing to keep the water from pushing sand out. I don't think it's just completely blowing the sand out while backwashing. I ran my hand through the waste stream while backwashing and did not notice any sand....but I know it went somewhere. With 0 pressure on the system (backwashing) I'm getting 50-60 gpm through the waste line (bucket calculated) but the filter is designed for 60 gpm.

OK, here is a slight update to this thread. I received the taylor test kit and I'm impressed. I wish I had bought this thing years ago. I had used several different kits in the past but this one is definitely top notch and accurate. It even comes with a little book that is full of useful information about not only the test kit but why the colors sometimes are flaky.

Here's my #s for today.
FC = 3.0 (as measured with the .2 ppm method)
CC= 1.0
Alkalinity = 200 ppm (may be slightly less, I elected to use the 25 ppm multiplier to save on reagents).
Hardness = 300
pH =7.4
CYA = 30

Pool water is much better after changing the sand. I'm still curious as to why I have lost sand. When I bought the pump/tank I sized the tank for the pump. The tank is good for 60 GPM, but I did measure the open ended output and it is in the 60 GPM range. I'm curious if any of you had run into this problem and if I need to simply add a bag or two of sand per year to prevent this from happening.

Even though my water has gotten much better it still is not that "crystal clear" I was looking for. I'm seriously considering switching back to a DE filter and I noticed that most of the mods etc. use sand filters. Is the hassle of adding the DE really not worth the better efficiency?

Thanks for your replies.

Although many people swear by their DE filters, ALL the mods use sand filters -- although Janet switched to Zeo a year or two ago. It is so much less hassle and honestly, I'm not sure my water could get any clearer with something else. Have you tried added a little DE to your sand filter?

Since you have CC of 1.0, you need to shock the pool again. For a CYA of 30, that would mean shocking it up to 15ppm. I would just use bleach if I were you since you are battling cloudiness. In an 18K pool, each gallon (4 quarts) of 6% bleach will add about 3.3 ppm of cl. Keep your chlorine at shock level as consistently as you can until your water clears, you have no higher than 0.5 CC and you can go from sundown one evening until no longer than 2 hours after sunup without losing more than 1ppm of cl. It may take a couple of days, but with a working filter and consistent shock level, it should clear up. Also run the pump 24/7 while you are trying to clear it.

Thanks so much for your info.

I tested the water again this morning. I really love this Taylor test kit, thanks for the tip.

OK, yesterday evening when I tested it was getting a little dark, so I wanted to double check all my tests in good sunlight. Everything matches up except the CYA. I messed that one up, the CYA is most likely around 10 or so. When I get the tube to the 30 ppm mark, the dot fades significantly, but not completely. I can fill the tube all the way to the top before it disappears. Pool store tested it at 10 ppm, which is what I think is true. I know that I only have a few more tests left with this kit but I think I can get the CYA test solution at Wal Mart.

Here are this mornings #'s.
FC = .8 ppm
CC = .6 ppm (both using the .2 ppm method)
pH = 7.4
TA = 200-225 (using the 25 ppm method)
CH =300-325 (using the 25 ppm method)
CYA <30 (less than 30). Most likely around 10 ppm.

Water is looking much better, starting to get that "blue" tint to it again. Even lately when the water has been improved it has still had a green tint. Yesterday I scrubbed the walls and trouble places like corners and jets where the algae tends to cling. I also set my filter to run 2 hours during the night so that it doesn't sit so long without being turned over. I had it set to run from 9 am to 9 pm.

What I'm really interested in is has anybody ever come up with a solution to keep the sand level in the filter at the right level? Add some to the skimmer? Pop the top? I think if I marked the level in the filter using a really bright light I could keep tabs on it. When I had the filter apart I noticed that it allowed some light to pass through, so I was thinking that I could hold a Qbeam next to it at night to see if I could see the level. Kind of like when you stick a flashlight next to your hand at night and can see the red glow etc. I'll make sure not to melt the filter though, so don't worry about that, LOL.

Hey! Glad to hear there is progress!

If you really want it to clear up more quickly, do as advised here and test and add chlorine a few times a day and leave the pump running 24/7 until you conquer the beast;)

Brushing the pool is GREAT! - it gets the chlorine into the 'low interface' areas and stirs up any algae that is still trying to keep it's hold.

How high is the sand in your filter - it should be ~ 1/2 way full - the filter needs a certain amount of 'head room' to filter properly, if it had been overfilled in the past, that could explain why some is coming out when you backwash.

Thread update: Today my water is crystal clear. I don't know where the credit lies, but after getting my stabilizer levels up (finally), keeping the chlorine levels up, and in general keeping a watchful eye on the pool chemistry my water is as clear as I've ever seen. I am completely thrilled.

Believe it of not I have actually decreased the pump run time since installing the SWCG by a few hours per day. I think the pool has found it's balance.

I'm really glad your pool is under control!

Thanks for the update! I hope the rest of the season is without issue. :)