Pool out of control or Pool maintenance man out of control?

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flyer
Pool Newbie
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Posts: 3
Joined: Thu 03 Sep, 2009 16:40
My Pool: 8m x 4m pool in southern spain, sand filter, maintained by local ex-pat
Location: UK & Spain

Pool out of control or Pool maintenance man out of control?

Postby flyer » Thu 03 Sep, 2009 18:56

My pool is in southern spain, looked after by a local british "pool man". No problem to speak of for the last 6 years the pool has been operating, water has usualy been sparkling blue but this year one problem after another. Three or maybe four time this summer disaster, green water requiring each time anti-algae treatment, shock and clarifyer/floculant(?). Just tonight another call from our "expert" as I was settling down to watch "The Wire"

Our pool set up is sand filter, 3.5 m x 7.5 m, average depth 1.4m 36.7 m3, triclor tablets used, pool man puts 1 a week, in the skimmer plus breaks one up and throughs in pool. I've no idea about the pump & motor. During the two week period I have visited in August, as a layman I had measured and noted the following; PH value look good 7.2, chlo values constantly low, 0.0 to 0.6 on some readings, 0.6 to 1.2 other times, pressure on the only valve, on top of the filter, about .4 bar, 6 psi. A gushing sound in the filter housing, perhaps this normal.

We have had some incidents involving visitors ( we let the house out) - chino (gravel) dropped by little hands down the pipe leading from the skimmer basket, some had reached as far as the non return valve before the strainer basket, also some child's clothing trapped in the basket. But I don't think these incidents explain all the occurences of pool turning green. Also this summer has been hot, up to 37 degrees C. Poolman has suggested visitors topping water up with tap water has caused a problem, not sure what they should be topping up with if not tap water. - dry martinis?

Another environmental problem apart from high temperature and little meddling hands, we are high in the mountains, dry and dusty and sometimes strong winds so dust in the pool.

Last year I had asked our pool man should the sand be replaced, six years on from initial instalation. He was non-commital. I has since researched and discovered it is not everyones' favourite job. I raised this again, he now is suggesting it is a priority. I am wondering if this is the blind leading the blind. Probably it is a priority having researched a little, channeling or is it clumping of the sand? etc. But what of the low pressure at the gauge, would this support this theory or indicate a poorly performing pump. In any case would poor filter perfomance result in our regular growth of algae or would this be due to insufficient chlorine tablets? Pool man suggests he keeps tablet usage low to keep costs down. I am stuck, my wife has just broken her shoulder and I can't just jump on a plane and pop over to Spain, I'm not sure my pool man is up to this problem. Any Ideas? :(


mypoolsupplyguys
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Pool out of control or Pool maintenance man out of control?

Postby mypoolsupplyguys » Thu 03 Sep, 2009 22:37

You are supposed to top the water up with regular tap water. Like you said? What else are you supposed to do? Wait for a nice rain?

Judging by the comments of the chlorine to keep the cost low, etc. He is the pool man, thats why you pay him, to keep your pool clean no matter how many chemicals are needed. It is his responsibility to raise the cost to service your pool if it requires more chemicals or becomes a problem pool.

My suggestion would be to call around for another pool man.
James007

Pool out of control or Pool maintenance man out of control?

Postby James007 » Fri 04 Sep, 2009 02:13

Your pool-person is incompetent. If they can't keep your pool clean and algae-free, then they do not know what they're doing.

First, they are using too much trichlor. The trichlor contains a lot of cyanuric acid. When the cyanuric acid levels get too high, the chlorine reaction rate slows down to a rate too slow to prevent algae. You need to measure the cyanuric acid level and make sure that it is less than 70 ppm.

The chlorine has to be kept very consistent at 7.5 % of the cyanuric acid level. The pH and chlorine need to be checked and adjusted every day.

The algae is being caused by a free chlorine level that is less than 7.5 % of the cyanuric acid level. The best source of chlorine is from liquid chlorine or regular, unscented 6.00 % bleach. You could also use a Salt Water Chlorine Generator as your chlorine source.

Second, they should not be throwing trichlor in the pool. It is not safe.

Third, the tap water should not be causing a problem.

Fourth, sand can last for 20 years if the water chemistry is properly maintained. As your chemistry is clearly not being properly maintained, the sand may need to be changed.

You should get a Taylor K-2006 test kit and measure all of your chemical levels.

Information needed about the pool:

Free chlorine
Combined Chlorine
pH
Total Alkalinity
Calcium
Cyanuric acid.
Total Dissolved solids.
Temperature
Pool volume in gallons
Pool length, width, average depth, deep end depth.
Pool Type: Fiberglass, Vinyl liner, Concrete, tile?

Chemical readings needed for the tap water

Free chlorine
Combined Chlorine
pH
Total Alkalinity
Calcium
Total Dissolved solids

If you can provide this information, someone should be able to better assist you.
flyer
Pool Newbie
Pool Newbie
Posts: 3
Joined: Thu 03 Sep, 2009 16:40
My Pool: 8m x 4m pool in southern spain, sand filter, maintained by local ex-pat
Location: UK & Spain

Pool out of control or Pool maintenance man out of control?

Postby flyer » Fri 04 Sep, 2009 05:57

James, thanks for your helpful reply. Unfortunately I cannot provide all of the information you have asked for as I am currently in the UK. I did carry out a partial test of the tapwater, PH and Chlorine, Ph about 7.6, chlorine 0.3-0.6. Our tapwater is provided by our pueblo and comes from our mountain, a huge limestone sponge. I will have to read up on some of your reply as much was above my head, you have given me some pointers though. Thanks.

One question, you say our poolman is using too much triclor, 1 to 2 tablets a week? The box says 1 tablet per 20 cubic metres. Our pool is about 37 cubic metres.

I will be looking for the test kit your mentioned though I wonder if it available in Spain.
APSI

Pool out of control or Pool maintenance man out of control?

Postby APSI » Fri 04 Sep, 2009 13:26

I would test for Phosphates. Algae is adaptive to chlorine if phosphates are present. Phosphates serves as food for algae growth, as long as food is present destruction of algae is very difficult especially during algae bloom seasons. If phosphates are present, atleast 200ppm then a phosphate remover chemical could be used. Be warned though if currently phosphates present it would be in solution and thus you will not see it. when the phosphate remover added to pool it pulls the phosphates out of solution being a solid and clouding your pool until it is filtered out.
chem geek
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Location: San Rafael, California

Pool out of control or Pool maintenance man out of control?

Postby chem geek » Fri 04 Sep, 2009 13:42

Phosphate removers should be seen in the same vein as algicides. They are not the only way to control algae growth. First of all, the phosphate removers remove orthophosphate, but not organic phosphates and small organic phosphates can still be used by algae for growth, though more slowly. So it's not always a cure-all though it usually helps a lot just as a PolyQuat 60 algaecide applied weekly would help, but it is not necessary if proper chlorine levels are maintained.

The bottom line is that chlorine alone can absolutely control green algae growth regardless of the algae nutrient (phosphate, nitrate) level. I have 2000-3000 ppb phosphates in my pool and others have 4000+ phosphate levels and don't get algae because the Free Chlorine (FC) level in these manually dosed pools is kept at a minimum of at least 7.5% of the Cyanuric Acid (CYA) level. Higher CYA levels require higher FC levels to have the chlorine kill algae faster than it can grow. This chlorine/CYA relationship has been known since at least 1974 (in this paper ) even though it isn't taught in any courses (i.e. NSPF CPO or APSP TECH). Other chemical facts that aren't taught are the following:

For every 10 ppm Free Chlorine (FC) added by Trichlor, 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 7 ppm.

Even with a low daily chlorine usage of 1 ppm FC per day, using Trichlor would increase the CYA by over 100 ppm in 6 months if there were no dilution of the water.

Learn more about how to maintain a pool at the Pool School .
James007

Pool out of control or Pool maintenance man out of control?

Postby James007 » Fri 04 Sep, 2009 21:47

When I say that the pool person is using too much trichlor, I mean that they should not be exclusively using trichlor. Trichlor contains cyanuric acid (Also called stabilizer). If the cyanuric acid level goes above 100 then the chlorine will not continue to work properly. The pool person needs be using an unstabilized form of chlorine such as liquid chlorine that does not contain cyanuric acid.

You should ask your pool person to e-mail you the requested information. If they are even halfway competent, then they should already know this information. If they cannot get you this information within 3 days, then I would recommend that you find someone else to service your pool.

Also, add phosphates levels to the list of information needed about your pool. Usually, you can disregard phosphates. I can better advise you after you post all of the requested information.

You can totally trust chem geek; he is one of the most knowledgeable people about pools and water chemistry.
ben.N

Pool out of control or Pool maintenance man out of control?

Postby ben.N » Mon 14 Sep, 2009 22:41

stop using trichlor weekly! he only uses it so he doesnt have to spend money on chlorine and acid seperatly
has he backwashed the filter??
patrickspools

Pool out of control or Pool maintenance man out of control?

Postby patrickspools » Sat 10 Oct, 2009 11:19

"The chlorine has to be kept very consistent at 7.5 % of the cyanuric acid level. The pH and chlorine need to be checked and adjusted every day."

James are you serious? If this were true I would be a millionaire. Once a week is easily good enough....I think if I tried I could keep 90% of pools algae free doing the chems once a month as long as they had a chlorinator.

When I read the original post the fist thing that came to my mind was high phosphates like APSI said. The pool probably had one of the following bad things happen:

1. Leaves sat on the winter mesh cover rotting in pool water that was too high.
2. The winter cover is a tarp style cover that fell in or was dumped in spring.
3. The landscaper decided to fertilize the pool along with the lawn.


I personally do not change sand in sand filters. I think that whole need is a myth created by pool guys who needed work. I've cut open my fair share of 20 y/0 sand filters and the old sand and the new sand I am putting in the new filter looks identical.

I also don't think filters in general are even needed to keep a pool algae free....just the right chemicals. My company has maintained plenty of pools for extended periods with no filter/pump. This year we maintained a pool for 6 months with no filter/pump. The only filtration was once in blue moon my employee would do a cartridge vac. The pool never had a hint of algae.

Also would like to point out one more thing. Using tabs alone is fine. Its the cheapest way to keep the pool sanitized. We use as few as possible to maintain our 3-5 ppm that we need. We stack them so there is less surface area and they last longer. We put them in a chlorinator turned way down, or the furthest/weakest skimmer in a poorly plumbed system.

I am no chem wizard but I am assuming through fall and winter pump downs, leaks, evaporation, and backwashing that we lose enough water that our stabilizer never gets too high. I've been successful with my methods for about 20,000 weekly services so I'm pretty sure tabs alone is OK.
chem geek
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Pool out of control or Pool maintenance man out of control?

Postby chem geek » Sat 10 Oct, 2009 12:41

There is no one singular approach. However, if you use only Trichlor tabs, then you either need to 1) dilute the water significantly to keep the Cyanuric Acid lower or 2) use supplemental products to prevent algae growth (weekly algicide or use of phosphate remover) or 3) use a higher FC level (regular shocking does this as well).

If the pools are smaller and backwash weekly and/or there are significant summer rains with overflow, then water dilution can keep the CYA somewhat in check. However, I can tell you from personal experience in my own pool with a cartridge filter and no summer rains and a pool cover with a pool cover pump in the winter there was very little dilution. Trichlor pucks in a floating feeder even at a low 0.7-0.8 ppm FC per day chlorine usage led to a rise in CYA from 30 ppm to 150 ppm in just one and a half seasons of use. Even though I was using an algicide every other week, my chlorine demand started to shoot up and the water started to turn dull -- a nascent algae bloom.

Could I have used a phosphate remover? Yes, though with 300-500 ppb phosphates in my fill water it would have become expensive. Could I have used the algicide weekly instead of every other week? Yes. However, I decided to learn what was really going on in my pool and now I only use 12.5% chlorinating liquid added twice a week (due to the opaque pool cover the chlorine loss is low at < 1 ppm FC per day) with a stable pH that only costs me around $17 per month for my 16,000 gallon pool shown here .

If your pools have 3-5 ppm FC, then if there was no use of algicide or phosphate removers, the worst of such pools would probably get algae somewhere around 60 to 100 ppm CYA though at first it would just appear as an unusually high chlorine demand. So one might shock the pool with higher FC and this would buy more time as the CYA climbed higher with continued use of Trichlor. If there were significant rains throughout the year, then that could dilute the pool water enough to keep things OK in most such pools.

There are over 20,000 pool users at The PoolForum and over 10,000 at Trouble Free Pool plus hundreds if not thousands on this forum who maintain their pools algae-free with chlorine alone at low cost by understanding the chlorine/CYA relationship. It is not the only way, but it is low-cost and easy to do, though not as convenient as Trichlor since you need to add chlorine more frequently (unless one has a chlorine dosing system such as The Liquidator or a peristaltic pump or a saltwater chlorine generator system).

It's not that one can't use Trichlor, but that one should understand the consequences. Trichlor is not the cheapest when you account for the pH adjustment products you need to use. A cost comparison of chlorine sources is here .

There have been many, many pool users using Trichlor only that get algae -- it is the most common reason for algae problems reported on multiple pool forums. Could they spend more money on algicides or phosphate removers to try and control the algae? Yes. Do they have to? No. Chlorine alone can prevent algae growth, independent of algae nutrient level (phosphate, nitrate). It is the FC/CYA ratio that determines the active chlorine level, NOT the FC level alone. This is known science since at least 1974 as definitively determined in this paper .

Richard

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