Help! Can't keep chlorine level up.

[FrogmanMickey]

This is my first post. I have maintained my pool myself for over 20 years, but it is defeating me now and I have not received the help I need from the local pool supply store. I hope you can help.

1) The size of your pool in gallons - 28,000
2) The type filter you have - DE
3) If your pool is an AG (above ground) or IG (in ground) - IG
4) If it's IG, tell us if it's vinyl, plaster/pebble, or fiberglass - plaster
5) If you know, tell us the size pump and the size (flow rate) of your filter -
Pump: Hayward Super II 3015EEAZ 1 ½ HP rated 90 gpm @ 60 ft. TDH
Filter: American Products Titan S.S. 60 sq. ft., normal flow 90 gpm, max flow 120 gpm
6) Other: Kreepy Krauly pool sweep, Pool Devil surface cleaner
Pool Location – Concord, CA

The problem:

I am having a devil of a time keeping the chlorine level up in the pool. I have been using four 3” tablets per week; two in a floater in the pool, one in a floater in the spa, and one in an inline leaf trap in the Kreepy Krauly hose. That used to be sufficient. However, now, without extra treatment, the chlorine level goes to zero. To try to combat that I have been socking the pool twice a week with a gallon of liquid swimming pool chlorine (12.5%). A couple of years ago, I used to do that every 10 days. Now the effect lasts for only about two days. Since the chlorine level goes back to zero, I have been trying to prevent algae growth by adding 8 ounces of Leslies Algae Control and 16 ounces of hth AlgaeGuard per week. Two years ago I was using only the Leslie’s Algae Control and that worked well that first year that I used it. But last year it seemed to be less effective and this year I was getting some algae growth even with this treatment, so I added the hth Algae Guard hoping that using a different chemical would add to the effectiveness.

I have a test kit, including a TF CYA test, but I have also taken samples to be tested at Leslie’s Pool Supply. Here is what they found the first time:

pH - 7.3
TA - Total Alkalinity - 110
FC - Free Chlorine - 0
TC - Total Chlorine – 0.5
CH - Calcium Hardness - 450
CYA - Cyanuric Acid (stabilizer) – 60
TDS – 2100

They said that my problem was the free chlorine/total chlorine ratio and that I should shock the pool with 3 lbs of Leslie’s Power Powder Plus, which I did. Of course that shot the chlorine level way up, but the effect only lasted about 4 days. Two weeks later, since I was going on vacation for 6 days and was not going to be there to put the liquid chlorine in the pool, I took another sample to Leslies to see if the problem had been corrected. Here is what they found:

pH - 7.2
TA - Total Alkalinity – 100
FC - Free Chlorine - 0
TC - Total Chlorine – 0.5
CH - Calcium Hardness - 450
CYA - Cyanuric Acid (stabilizer) – 60
TDS – 2200
Phosphates - 500

I should mention that when I tested for CYA with the TF test kit I got a higher value (more like 100) but the test is a judgement call and I assume the people at Leslies are more skilled at doing this test than I am so I imagine their results should be believed. However if having a much higher CYA level than Leslies measured could be the problem, I wanted you to know that I obtained a higher value than they did.

This time they told me to put in 4 lbs of Chlor Brite granular chlorine and fill up my floaters prior to leaving on vacation, which I did, so there were 3 tablets in each floater when I left. I broadcast the Chlor Brite over the pool surface. I also dosed the pool with the Algae Control and AlgaeGuard. When I returned 6 days later, the chlorine level in the pool was zero again, even though there was still the equivalent of about 3 tablets left in the floaters (so about 3 had been consumed). So I socked the pool with a gallon of liquid and am back to the routine of doing that twice a week again. By the time I put the next gallon in, the chlorine level has gone to zero. It looks like a gallon every other day would keep the level up throughout the entire week, but since I am holding the algae at bay with the current routine, I have contined with the 2 gallons per week treatment.
.
How the water looks:
It is generfally crystal clear, but when the chloring level goes to zero I can get green algae starting to show up in a few isolated places, e.g. in the grout in the tile at the water line, on the hose connection for the Pool Devil surface cleaner, and in a couple of places on the plaster where the Kreepy can’t go. I have also noticed what appear to be light pinkish patches on the plaster. These can be brushed off with some effort, and they disappear when the pool is shocked. I don’t know if there is such a thing as pink algae or what this is.

The water in the pool has been there since November 1999 when the pool was replastered. Of course some of it exchanges in the winter when the rains cause the pool to overflow into the runoff drain. The pool also gets 7 minutes of make-up water every day on a fill timer.

Even two gallons of liquid per week of liquid chlorine on top of the tablets does not keep the chlorine level up. The water has always looked good. I added clarifier at the beginning of the season but have not had to do so since. At night with the pool lights on, I don’t see any suspended solids in the water. The Kreepy and the DE filter keep it pretty clean. There is almost zero swimming load on the pool. My wife swims a couple times a week, if that, so I know that is not consuming the chlorine.

Now, if a high CYA level could be the problem, and the answer is to drain and refill the pool, I can’t do that. We live in a drought area and are under strict mandatory water rationing. The amount of water required to drain and refill the pool would incur a severe penalty right now. The rationing may be lifted during the winter, but for now I can’t even consider draining and refilling. So I need a different solution.

We have another longer vacation coming up. Because the chlorine level goes to zero if not attended to constantly (even with full floaters), I am worried that algae may bloom when we are gone. So I am looking for some help as to what to do about this problem. The solutions suggested by Leslies have not worked.

Thank You

 

[dravenone]

Douglas, trust YOUR test results. Leslie's is just out to sell you seomthing everytime you walk in the door. If you tested a CYA of 100 then the experts on this site are going to provide advice based on that result, and the other information you provided.

I used pucks for a long time and my CYA was off the charts. trust your TF kit and trust yourself. An expert will be along shortly to point you in the right direction, I just wanted to give you some words of encouragement.

 

[JohnT]

Welcome to TFP.

I would NOT assume the person at Leslie's is better at testing than you are. Going thtough tablets the way you are, your CYA has to be higher than 60 unless you are replacing a lot of water regularly.

Since you can't drain, you'll have to try to deal with it. First, stop using the pucks, and start adding liquid chlorine daily. Not as convenient, but it won't make the problem worse.

Your chlorine consumption is probably a symptom of excess biological debris in the pool. The best way to get over that hump is to shock the pool. For CYA of 100, the recommended shock level is 39ppm. I know that sounds high, but your CYA will buffer it and it will not hurt anything. Raise your chlorine to 39 or 40ppm with liquid shock, and keep a close eye on the chlorine for a couple of days. Use poolcalculator.com to figure your dosage. How often you'll have to add more is hard to say, but check at least every 4 hours to start with. When it holds the shock level overnight without adding anymore, let the chlorine drop to the recommended chlorine level for 100ppm CYA, which is 12ppm.

If you keep your chlorine at 12ppm, you should have clean water with no chlorine smell or algae.

For more info, read the following Pool School articles:

pool-school/chlorine_cya_chart_shock

pool-school/shocking_your_pool

pool-school/overnight_fc_test

 

[PaulR]

Like John says, inability to maintain FC probably means you have something using it up. You can be certain of this if you do the Overnight FC Test.

The CYA test often looks like it reads 100 when it's actually higher. Try using a water sample that is 1/2 pool water 1/2 tap water and see what you get (double the result). If it still says 100, use 1/3 pool water 2/3 tap water. And so on.

There was somebody else from the East Bay recently with a similar excessive CYA situation; I think they are now using the pool water for irrigation and using fresh to refill the pool (instead of using fresh to irrigate). That level of usage should stay within the drought restrictions.

The one concern I'd have with you doing that, is that you've been using HTH products; they often have copper in them, and I simply don't know whether it would be enough to adversely affect the vegetation. You should check the ingredients, and ask Leslie's to do a copper test; and maybe somebody else can chime in regarding whether it would be safe for plants.
--paulr

 

[frustratedpoolmom]

I don't see any reason why the copper would hurt anything if pool water is used to water the lawn, etc. If you have it in the water, I'm sure the levels are very low as to not be a problem. I don't think the algae guard is a copper product, but I could be wrong. I think it's just a cheap linear quat, and it can cause foaming.

At this point if you feel draining is not an option for you, then you must maintain your FC level according to the CYA chart (once you know accurately what your CYA is)... and you should only be using liquid chlorine or bleach.... in order to prevent/kill algae. I absolutely would trust your own testing. There have been numerous posts about poor testing at pool stores, Leslie's included. Here's a thread that might help you when doing the test:
http://www.taylortechnologies.com/ChemistryTopicsCM.ASP?ContentID=44
If you get 100, try the dilution method as suggested.

Once you complete shocking, and confirm the algae is dead with an overnight loss test, then you have to maintain the "target" level, staying above the "min" FC for your CYA at all times. THis means daily bleach additions to prevent the return of algae. So you'll need to have someone add it for you while you are gone, or potentially have a green mess on your hands when you return. Don't use the HTH algaecide, it's not worth the money. The Algae Control brand, if it's the 60%, is PQ 60 equivalent and is a good product, but you have to add the proper dose weekly for it to be effective.

You have to have a FAS-DPD test to do the Overnight Loss test. What kind of kit do you have?

Yes, there is pink algae (it's actually a bacteria).

Under the right conditions, you could get Lucky enough, LOL....bear with me, this is kinda outthere....some bacteria, when the chlorine level is allowed to fall to zero, can consume CYA and convert it to ammonia. This has been well documented on several threads on the forum this summer-google search (the bottom left corner) "ammonia". Then the pool owner experiences a very high chlorine demand when oxidizing the ammonia, iyou still have to shock with massive amounts of chlorine, but the CYA goes to zero. Now I'm not suggesting this is the route you take, but it is a possibility, just thought I would throw that out there. It doesn't always happen, and that is not clear why it does.

So if you don't have anyone to add bleach, if the pool's gonna turn green, you might get lucky and come home to find the pool is green and the CYA is zero.

Hope this helps. IF you need any clarification just holler....

 

[FrogmanMickey]

Hi everybody

I guess this is the way to keep the conversation going?

Thanks for your immediate and thorough responses.

To clarify the algae control chemicals I am using:

The hth Algae Guard label reads:
n-Alkyl (60% C14, 30% C16, 5% C12, 5% C18) dimethyl benzyl ammonium chlorides – 10%
methyl benzyl ammonium chlorides - 0.04%

The hth web site calls it -10% quaternary ammonium chloride “Quat”
It is a non foaming formula (and, in fact, I do not see any foaming in the pool)
There does not appear to be any copper in it.

The Leslie’s Algae Control label reads:
Poly[oxyethylene(dimethyliminio)ethylene(dimethyliminio)ethylene dichloride – 60%

The Leslies Algae Control costs about $75 per gallon whereas the hth Algae Guard costs only about $10 per gallon. Used according to label instructions, I have to use twice as much hth as the Leslie’s Algae Control, but the hth is still quite a bit cheaper. In any case, since it appears that they are different chemicals and therefore might have a different effect, I am using both.

I don’t know where any excess biological debris might be coming from that would consume the chlorine. As I mentioned, no one uses the pool and it is clean except for a few leaves and twigs that get into it occassionally, but I remove those regularly if the Kreepy doesn’t get them.

I liked the idea of irrigating with pool water and filling the pool with tap water, but it is not very practical in my case. Between the front and back yards I have 8 irrigation circuits to lawns, shrubs, trees and a vegetable garden all on automatic controls and all set to various watering times and amounts according to the type of vegetation. Careful watering management is needed to keep within the rationing allotment while still keeping all of the landscaping alive. To use pool water would require a pump (which I don’t have) and some way to feed all of the various areas. I am not sure how I would acomplish that. My entire water usage for a month, including household and irrigation, is about the capacity of the pool, so it would take months to exchange the pool water using this method. I might be better off now just waiting for winter when hopefully the rationing will be lifted and just renting a pump, pump the pool water to the storm drain and refilling,

Here are a couple of questions about your suggestions I hope you can answer.

1) Since the consensus seems to be that I need to raise the chlorine level to about 40 and keep it there until it stays up over night then maintain it at about 12, how do I measure that? My Guardex test kit (where you compare color) only goes up to 3. And I am pretty sure I can’t do FAS-DPD with this kit.
2) According to the Pool Calculator, to raise the chlorine in my pool from zero to 40 requires about 9 gallons of 12.5% pool chlorine. Does that seem right? It costs about $3.00 per gallon where I buy it, so are we talking about putting in $30 worth of bleach? (According to the pool calculator I would have to use 18 gallons of 6% household bleach. For 6% household bleach to be a better deal it would have to cost less than $1.44 per gallon, which I don’t believe it does, at least not around here).
3) For the upcoming vacation, I am thinking about quadrupling the Algae Guard dosage, as the container recommends for the initial dosage at the start of the season. What do you think about that?

Thanks for all of your help.

 

[Titanium]

Frog,

I don’t know where any excess biological debris might be coming from that would consume the chlorine.

The UV radiation in sunlight will consume chlorine.

Re: $3 per gallon of 12.5% chlorine

We pay $7 for 2 gallons of 10%, so our $3.50 per gallon of 10% is a little bit more expensive than you are paying.

need to raise the chlorine level to about 40 and keep it there until it stays up over night then maintain it at about 12, how do I measure that? My Guardex test kit (where you compare color) only goes up to 3. And I am pretty sure I can’t do FAS-DPD with this kit.

Your kit can not read this high. You are going to need a kit that can do FAS-DPD - either the TAylor K-2006 or the TF100.

http://www.troublefreepool.com/pool-school/pool_test_kit_comparison

 

[frustratedpoolmom]

You need a better test kit.... either the TF100 or the Taylor K-2006.

As for the algaecide, you get what you pay for.

The algeacide use also consumes some of the chlorine, just an FYI. I don't know that quadrupling the dose will help. Maybe double it at the most. Do not be tempted to do that with the HTH - it will foam for sure if you dump that much in at once.

 

[PaulR]

I liked the idea of irrigating with pool water and filling the pool with tap water, but it is not very practical in my case. ... To use pool water would require a pump (which I don’t have) and some way to feed all of the various areas.

A small sump pump isn't that expensive, but hooking it into an existing irrigation system would be a bear. Maybe trade one or more of the lawn zones for the kind of sprinkler you run off a garden hose that you run from the sump pump... extra manual effort, I know. Totally up to you, of course, I'm just trying to point out viable alternatives. If you decide to wait for winter I'm not going to complain. (I wish I had when I did mine, but that's another story.)

Regarding FAS-DPD you do not have to buy a whole new kit, you can get just the FAS-DPD test from Taylor Technologies direct, or from tftestkits.net.

Regarding amount of 12.5% chlorine, adding one gallon of that to 10,000 gallons will raise FC by 12.5 (basically by definition of parts-per-million). Since you have 28k gallons and want to raise by 40, that's roughly 3 times the water and 3 times the ppm, so about 9 gallons sounds right.
--paulr

 

[Johnny B]

Where do you guys get this 10% & 12.5% chlorine? Those prices are much better than 6% bleach; about half price.

Thanks

 

[frustratedpoolmom]

I get mine at the local pool store. But it's not available everywhere, some stores choose not to carry it all. You'll have to shop or call around.

I saw some HTH brand 10% in a 2 gallon box at Wal-mart for about $7-8 bucks in the pool department, which isn't a fabulous price but doable, and I can't vouch for how good it is. Clearly they don't push the product since it was stored on it's side despite the warning on the box that it might leak.

 

[FrogmanMickey]

Hi everybody

Thanks for all of the great advice and tips. I have ordered the test kit and I bought two cases of liquid chlorine which I will apply as soon as I receive the test kit so I can measure the chlorine levels.

I did the CYA test with pool water diluted 50% as suggested, and this time got a reading of 80. So the advice that a reading of 100 frequently means the CYA is actually well above that is true. I diluted the water 50% again and got a reading of about 40. So it seems the actual CYA may be around 160 rather than 100 (or 60 as Leslie’s said). It is apparent then that the CYA has got to come down. Being under water rationing, the only way to do that is to do as was suggested - irrigate the landscaping with pool water and fill the pool with fresh water. So using a few PVC fittings and a couple of garden hoses, I figured out a way to tie the pool pump discharge into my irrigation feed manifolds. (There was a handy fitting available in the pool pump discharge pipe that used to be the supply to an old Arneson Pool Sweep which is long gone). Note: I also disconnected the irrigation feed manifolds from the house supply so there is no possibility of backflow of pool water into the house. But since I have valves and unions installed in the irrigation manifold feed pipes, it is a simple matter to reconnect (which I will have to do when shocking the pool since the plants may not appreciate water with 40 ppm of chlorine in it). Now all I have to do is throttle the valve in the pump return piping, initiate the irrigation cycle at the irrigation control panel and run the pool pump, and the yard is automatically watered using pool water. It is still a semi-manual operation. I could not completely automate it because, without throttling the valve in the pump return piping and pulling the Kreepy Krauly hose out of the skimmer connection, I could not develop enough pressure in the irrigation system. But with the suction unrestricted by the Kreepy, and the flow directed almost completely to the irrigation system, I can get a pressure of about 35 psi at the filter, which is sufficient. Note: I don’t completely close the valve in the pump return piping to allow a small flow back into the pool so the pump is not operated at shut-off head when the irrigation cycle concludes. Then I have to go back out and put the system back into pool circulation and cleaning mode. But the whole routine takes only about 5 minutes, and the system will water all 8 circuits by itself (which takes about an hour and a half). It is a bit inconvenient but at least there is no dragging hoses around. I also re-programmed the pool make-up water timer for a longer flow duration to replenish the water used for irrigation. A typical irrigation cycle only draws the pool level down an inch or so, so there is no danger of the skimmer going dry during irrigation. We still have a month or so left in the irrigation season here so hopefully I will be able to reduce the CYA somewhat in that time. If I had done this at the beginning of the summer instead of at the end I would probably be good by now. Oh well. Live and learn. But perhaps this thread will help someone else who encounters this problem in the future. In the winter, hopefully the water rationing will be lifted and I will be able to pump out the pool and refill. But having already replaced some of the water with fresh using the method described above, it should not require as much water replacement then to bring the CYA level down to where it belongs.

So, thanks to everyone who chimed in. That was a good brainstorming session, I think I may be on my way to restoring the health of my pool. I could not have done it without you.

P.S. I get my 12.5% liquid chlorine in cases of 4 one-gallon bottles per case at the local Ace Hardware (the Clayton Rd store in Concord, CA) for $3.00 per gallon. But I know not all Ace Harwares have it. The one near me has an outdoor yard where they can store it safely.

 

[PaulR]

So using a few PVC fittings and a couple of garden hoses, I figured out a way to tie the pool pump discharge into my irrigation feed manifolds. ...(100 page treatise omitted)...

The things some people will call "simple"... At least now I'm not sorry I suggested it!

P.S. I get my 12.5% liquid chlorine in cases of 4 one-gallon bottles per case at the local Ace Hardware (the Clayton Rd store in Concord, CA) for $3.00 per gallon. But I know not all Ace Harwares have it. The one near me has an outdoor yard where they can store it safely.

You should ask them how often they restock; it's not really great to store it outside, heat and time will cause it to degrade. If it sits in the sun more than a couple of weeks it won't be 12.5% anymore.
--paulr

 

[FrogmanMickey]

Re: The "100 page treatise". I know it was lengthy, but the idea was to provide enough detail to hopefully help someone else who might want to try it, anticipating questions/problems they might encounter.

Re: Liquid chlorine. The Ace store does not store it in the sun. The yard has a roof over part of it, which is where the chlorine is kept, so it is under cover. And they sell huge quantities of it, so the turn-over is quick.