At my wit's end - cloudy water

MikeH in NY · Postby **MikeH in NY** » Wed 27 Jul, 2011 15:21

Help! I want to give enough but not too much info, so here goes:

Our pool was not opened for two years, but I did open in this year. I took samples the the pool store a couple times a week, and it has come a long way from the frog pond it was. The problem is that even though my water is balanced (all the pool store seems to care about), it has never cleared up - it's so cloudy I can't see the bottom even in the 3 foot end. I have done everything the pool store told me to do and I run the filter/pump 24 hours per day (backwashing when needed). No matter what I do, it stays cloudy. I even tried old fashioned floccing - the floculent didn't sink, it stayed on top (yes, I raised the ph and followed the instructions exactly.)

I have a sand filter (the pool store doesn't believe the pool sand needs changing), and I am getting very good flow and pressure from the pump.

Any help is appreciated.

Mike H in NY · Postby **Mike H in NY** » Wed 27 Jul, 2011 15:29

Sorry, forgot the chem info, here it is (from the pool store analysis):

TDS 2200
CYA 70
Tot chlorine 9
Free chlorine 9 (I had just super shocked)
Total Alkalinity 170 (they said not to worry about that)
Total hardness 140 (said not to worry about that either)

Pool is 17,000 gallons, 16x32, 6ft deep end

I use chlorine, pucks in the skimmer and liquid to shock

Postby **chem geek** » Thu 28 Jul, 2011 00:53

The shock level with a CYA of 70 ppm is more like 28 ppm FC. Also, assuming your circulation is good but that your sand filter isn't catching finer particles you can try to Add DE to a Sand Filter for better filtration.

MikeHNY · Postby **MikeHNY** » Thu 28 Jul, 2011 08:53

Thanks for the response, chem geek. I had seen on the internet that adding a bit of DE might help, and my assumption really is that this cloudiness is fine particles. When I scoop a sample for the pool store, it actually looks clear. I am headed out shortly and will get a bag of DE.

I don't understand what you mean when you say "with a CYA of 70 ppm is more like 28 ppm FC." Does that mean the free chlorine is actually relatively higher than it tests? Remembering that it was a frog pond (literally), I did dump in a LOT of chlorine and I used a super algecide the pool store sold me. On my home test kit the total chlorine tests at about 2 today, I haven't dumped in any chlorine in 3 days, but I do have pucks in the skimmer. My ph is about 7.0. As far as appearance goes, I wouldn't say it's blue cloudy, and I guess I couldn't really say it's green cloudy, either, but pressed I'd say more green than blue.

Postby **chem geek** » Fri 29 Jul, 2011 01:27

What I meant was that with your CYA so high it will take much higher FC levels (about 28 ppm) to be effective for shocking. Shocking is NOT a one-time event. You need to SUSTAIN the high FC level by adding more chlorine. The fact that yours dropped so fast shows that it is oxidizing algae quickly and you need to raise it or else algae will grow again and you'll lose ground. Please read the Defeating Algae article in the same Pool School where I linked the DE in a sand filter page.

MikeHNY · Postby **MikeHNY** » Fri 29 Jul, 2011 07:27

chem geek wrote:What I meant was that with your CYA so high it will take much higher FC levels (about 28 ppm) to be effective for shocking. Shocking is NOT a one-time event. You need to SUSTAIN the high FC level by adding more chlorine. The fact that yours dropped so fast shows that it is oxidizing algae quickly and you need to raise it or else algae will grow again and you'll lose ground. Please read the Defeating Algae article in the same Pool School where I linked the DE in a sand filter page.

Actually it didn't drop all that fast. The original numbers I gave were from last week. I have been generally keeping the chlorine high, dumping in 30-35 gallons a week (17000 gallon pool), in addition to 4 or 5 pucks in the skimmer which dissolve over about 3 days. When it was a frog pond I started by dumping in 10 gallons per day for three days and had as many pucks as it would hold. This was the first time I took a break from putting in that much chlorine with the hope that someone might actually be able to enter the pool. This is all per instructions of the pool store.

As I stated earlier, it's mainly the cloudiness, and I can't really say it's green, although it's not blue, either. At any rate, five more gallons went in yesterday, and five will likely go in today - this makes it off the chart on my home test kit, the oto turns a dark orange. I also did the DE thing yesterday afternoon. No appreciable change noted this morning, and I did backwash because of high pressure/reduced flow in the evening.

Postby **chem geek** » Fri 29 Jul, 2011 10:58

If you backwash, then the DE is removed and you'll need to add more. The fact that the pressure increased so quickly is a good sign (assuming you didn't add too much DE -- only enough to see a 1-2 PSI increase initially) since it means things are getting removed from the pool.

Trichlor pucks increase CYA so I would not use them. Use only chlorinating liquid or 6% unscented bleach.

For every 10 ppm Free Chlorine (FC) added by Trichor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.

drain and refill · Postby **drain and refill** » Sat 30 Jul, 2011 00:14

you need to save money/time and dump your pool water and refill it or buy a better pool filter that can clean up a green swamp.

Postby **czechmate** » Sat 30 Jul, 2011 06:09

Advice is cheap.
New pool filter, that most likely is not needed cost around 600 bucks.

drain and refill · Postby **drain and refill** » Sat 30 Jul, 2011 19:26

Advice is cheap.
New pool filter, that most likely is not needed cost around 600 bucks.

Well use your AARP card then for a discount!
Like I said dump the water and refill the pool with fresh water as a sand filter will take forever or replace the filter with something newer and bigger that can handle this. I guess running your pool 24/7 for weeks is cheap?

I have been generally keeping the chlorine high, dumping in 30-35 gallons a week (17000 gallon pool), in addition to 4 or 5 pucks in the skimmer which dissolve over about 3 days.

enough said!

Postby **chem geek** » Sun 31 Jul, 2011 18:10

His pool is 17,000 gallons, not some sort of small Intex or pop-up pool. A full drain and refill is not necessary nor the least expensive approach. The water isn't even a swamp of a neglected pool. Clearing cloudy water is not rocket science, but as you point out does require a decent filter. Sand can be improved by adding some DE to it. If the particles are a suspension (as opposed to dead algae), then a clarifier can help, but usually is not necessary.

drain and refill · Postby **drain and refill** » Mon 01 Aug, 2011 08:43

If he has already dropped in 35 gallons chlorine and has been running his filter for 2 weeks 4/7 than replacing the water would have been cheaper and faster as its only 17,000gal.
The sand filter is probably on the small side and catching next to nothing. Know im not disagreeing with you it should cleanup if there was a better filter but theres not at this point and it shows just chemicals in water can not fix the problem.

Postby **chem geek** » Mon 01 Aug, 2011 11:50

I agree that he should have tried adding DE to the sand filter a lot earlier and not doing so that water replacement might have been less expensive (depending on water rates where he lives). Trying to clear a pool that has poor circulation and poor filtration won't happen quickly enough using chlorine alone. Also, I now see that in this post he described it as a frog pond prior to this cleanup, so that's worse than I had thought. 30-35 gallons in 17,000 gallons even assuming 6% bleach is 109 ppm so 15 ppm FC per day which is very high for an entire week. Something is very wrong in this situation -- either the CYA isn't as high as indicated (i.e. it's very low so the chlorine is getting lost from sunlight) or there are tons of organics in the pool (or algae growth).

Mike, did you ever get your own good test kit, either the Taylor K-2006 or the TFTestkits TF-100? The pool store reading for the CYA level might have been wrong. 30-35 gallons of chlorine in a week for your size pool is not normal even for a pool cleanup. Did the FC drop back to near zero within an hour or did it drop more slowly? If the FC drops quickly right away, then bacteria may have converted CYA into ammonia in the pool and that can create a HUGE chlorine demand (my personal experience about this is described in this thread). If the FC is dropping during the day but not at night, then you probably don't have any CYA in the water and the pool store reading was terribly wrong (not a surprise since they are often wrong). Has the DE in the sand filter helped clear the pool at all?

MikeHNY · Postby **MikeHNY** » Tue 09 Aug, 2011 16:04

My apologies, I hadn't been here in a while to look at responses as I have been trying to clean things up. I appreciate that there have been some new responses.

So, here are some updates:

The pool is still milky white cloudy, not green The swamp is long gone, believe me there is nothing alive in there. And the days of dumping in 5 gallons of chlorine at a time are also over, the chlorine has stabilized and I now only shock as I usually would with liquid (every 2-3 days).

For those who think the pump/filter might not be up to par, you are off base. I have super strong (actually stronger than ever) flow through the pump and back to the pool. The filter itself is a Hayward S220T and is 5 years old.

And, I am not about to change all of - or most of - the water. Nuf said about that.

Adding DE to the filter did not seem to do the trick. While I do get the 1 pound bump in pressure after adding and eventually have to backwash, then re-add, etc., this cycle has gone on for several days now (over a week) with no appreciable difference in the appearance of the water.

So I'm thinking maybe the sand does need to be changed after all? Or is that another waste of time/money? Keep in mind I live in upstate NY and swimming season will actually be over soon.

Postby **chem geek** » Tue 09 Aug, 2011 23:43

Well the milkiness could at this point be a suspension where a clarifier would help, but usually that comes from things like phosphate removers and not from just clearing a pool of algae. I used GLB® Clear Blue® once with good results (I was trying out a phosphate remover as an experiment from the manufacturer and the water turned very cloudy and I needed it cleared in a hurry). Normally clarifiers aren't needed and since they don't always work they aren't normally recommended, but since filtration alone isn't helping (not even with DE), then this would be the last resort to try (the other alternative would be a flocculant, but since you say your circulation is good then a clarifier should work).

It's very unlikely you would need to change the sand unless you had terrible channeling in the filter from a serious buildup of bacterial biofilm.