Minimun Phosphate Levels ??

Algae problems in swimming pool water.
Green (cloudy) water or slimy pool walls.
Black algae. Mustard algae. Pink or white pool mold.
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Minimun Phosphate Levels ??

Postby hoodfigga » Mon 12 Nov, 2007 04:58

Well after trying to clear up a green algae bloom for three weeks I think I have finally succeeded. I had to shock the pool twice. Placed a phosphate remover in it (PR-3000 orneada) and used SeaKlear algea Remover. All is fine now except my phosphate level is 200ppb. according to the pool store. I have a salt system and they say that 200ppb is not worth a treatment. Should I go ahead and try to lower the levels even further. Thank you....


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Phosphates in pool water

Postby chem geek » Mon 12 Nov, 2007 13:23

The short answer is no, you don't have to go further in lowering the phosphate level.

In a saltwater chlorine generator (SWG) pool, the Free Chlorine (FC) level should be at least a minimum of 4.5% of the Cyanuric Acid (CYA) level to keep away algae. A manually dosed chlorine pool usually requires a minimum FC that is 7.5% of the CYA level, but an SWG does superchlorination in the SWG cell and continual dosing that helps lower the chlorine requirement. Do you know what the water chemistry parameters were at the time the algae developed? The recommendation of most SWG manufacturers that an FC of 1-3 with a CYA of 60-80 is wrong and insufficient for keeping away algae (except the 3 ppm FC 60 ppm CYA combo).

You can use a phosphate remover or use PolyQuat 60 algaecide to keep away algae and use a lower chlorine level, but these are not necessary if you maintain the appropriate chlorine level relative to CYA level. Which approach you use is up to you -- both will work (i.e. chlorine alone, but with sufficient FC/CYA ratio vs. using either a phosphate remover or algaecide) -- the amount of chlorine needed to kill bacteria is much lower than that needed to prevent algae growth so the pool is still disinfected even with rather low chlorine levels. The bigger issue is not having enough chlorine capacity, FC, that you run out locally, but 1-2 ppm in a pool is usually sufficient if the CYA is high enough to protect chlorine breakdown from sunlight (60-80 ppm CYA). That is, the SWG manufacturer recommendation is fine for disinfection, but not for algae prevention (unless the 3 ppm FC with 60 ppm CYA combination is used) unless a supplemental algaecide or phosphate remover is used, but the least expensive approach is just to maintain a higher FC level.

There are quite a few pool users whose pools have up to 3000 ppb in phosphates and do not develop algae because they maintain sufficient FC levels relative to the CYA levels. One needs to look at phosphate removers as another alternative, similar to algaecide -- another tool in the arsenal, but not the only approach that is effective.

Also, be careful about what you use to shock the pool. Some products, such as Leslie's Chlor-Brite which is Dichlor or Leslie's Genesis Shock which is Trichlor, add to the CYA level just making chlorine less effective. For every 1 ppm FC added by Dichlor, it adds 0.9 ppm to CYA. For every 1 ppm FC added by Trichlor, it adds 0.6 ppm to CYA. Marketing such products for use as shocking with chlorine is irresponsible at best. Even Leslie's Power Powder Plus should make clear that being Cal-Hypo for every 1 ppm FC it also adds 0.7 ppm to Calcium Hardness (CH), though in percentage terms (since normal CH levels are near 300 ppm for plaster pools) that is usually not a problem unless used regularly. It is usually best to shock with chlorinating liquid (or unscented bleach) though if price were no object then Lithium Hypochlorite would be another alternative as these do not add to CYA nor to CH.

If you don't have one already, get yourself a good test kit, the Taylor K-2006, from Taylor here or from Leslie's here or from poolcenter.com here (careful: not the K-2005 -- make sure it's the K-2006) or the even better TF100 test kit from tftestkits.com here.

Richard
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Phosphates in pool water

Postby hoodfigga » Mon 12 Nov, 2007 20:31

Thank you for your reply. I must say that this forum and your reply has helped me immensely. As far as what my pool chemistry was when the algae started I could not say. Not because I was not checking but only because I have corrected and checked the water so many times that my head is spinning with numbers. My current shock treatments are only done with the super chlorination mode and extended run times on the pool pump. I have not used any other shock method only because I wasn't sure you could add other chlorination products to the pool when using the SWG. From your reply I see you can. From reading the forums and your reply I see now that the higher the CYA, the higher you have to maintain your FC. Am I correct? My present chemistry is a Ph of 7.5 , Alkalinity of 100 , and CYA of 60. Plaster pool in south Florida, 15,000 gal. I personally like to have the chlorine levels on the low side only because I do not like the dry skin feeling from high FC. I also feel that I need to maintain a higher CYA level because of the brutal long hot sunny days in South FL. In summation my plan is the following. Keep the CYA between 60-80 with a 1-2 ppm and use the algaecide. My algaecide of choice for the treatment and prevention is the SeaKlear Algae Prevention & Remover. The maintenance dose is 16oz of product for a 10,000 gal pool every 3 months. The cost is $17.00 for a quart at my local pool store. The seaklear product is a organo complex formula with copper. Yes copper! Oh Oh stains in plaster. I called the manufacturer and they say there product is triple chelated time released and there is almost a 0% chance of staining if the product is used per directions and the pool is balanced. I hope their right. Any suggestions or comments are welcome. On a side note I was using Jacks Magic Purple for metal control per my pool builder but I have decided not to use it because it is phosphate based. Any opinions on metal control with SWG systems would be greatly appreciated. Thank you.
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Phosphates algae and copper

Postby chem geek » Mon 12 Nov, 2007 23:22

Yes, a higher CYA needs a higher FC level to prevent algae if you are using chlorine alone for such prevention. If you use an algaecide or phosphate remover, then you can have a somewhat lower FC. If you maintain an FC level of 4.5% of the CYA level, so around 3 ppm FC with your 60 ppm CYA (absolute minimum of 2.7 ppm FC) then you shouldn't need to use any algaecide nor phosphate remover. This also should not dry out your skin or hair as this is a very low level of disinfecting chlorine. Nevertheless, if you want to run lower at around 1-2 ppm FC and a higher CYA level of around 80 ppm, then that would result in less disinfecting chlorine -- so you'd have to use an algaecide or phosphate remover. PolyQuat 60 algaecide will cost you around $2 per week and will keep away the algae. The phosphate remover may cost about the same in maintenance mode, but is much more expensive to initially get rid of higher phosphate levels.

I would not use the SeaKlear Algae Prevention and Remover product as this is copper sulfate. I don't care how much they chelate it, the chelation will break down over time and even if it didn't, then the copper concentration will be rather low and less effective. If there is enough copper in the water to prevent algae growth, then there is enough to stain if the pH rises and enough to turn blond hair green. If no one using the pool has blond hair and if you are very careful not to have the pH rise (including from shocking with chlorine) then copper could be OK, but with an SWG pool the pH tends to rise so pH control is harder. You are much better off using PolyQuat 60 from any of a number of brands such as GLB Algimycin 600 or BioGuard Algae All 60 (both products have 60% Poly{oxyethylene (dimethyliminio) Ethylene (dimethyliminio) ethylene dichloride} ).

You can use metal sequestrant products including Jack's Magic that are phosphate based because they aren't orthophosphate initially and even if and when they break down to become orthophosphate, phosphates really don't matter very much. If you are using an algaecide or a phosphate remover, it most certainly won't matter unless you get to extremely high levels above 3000 ppb. The use of phosphate removers are the latest way for pool stores to make a buck, but as I've said before they need to be seen in the context as an alternative algaecide and are not needed if you are willing to maintain sufficient chlorine levels. In your case, since you don't mind spending more to have a somewhat lower chlorine level, you can use PolyQuat 60 algaecide or a phosphate remover. I think the former is a better choice, but technically either approach will work.

By the way, with an SWG you probably find that the pH has a tendency to rise. If you lower the TA to 80 or even 70, then you should find it rises less quickly and that you use far less acid to adjust the pH. See this post for how to lower the TA using aeration and acid addition at a lower pH.

Richard
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Phosphates and algae

Postby hoodfigga » Tue 13 Nov, 2007 04:39

Your explanation is very clear. I will look for the PolyQuat 60. Better to be safe than sorry.
Yes you are right about the pH rising. I constantly find myself adding acid to the pool. I will look into the post about lowering the TA.
I will go back to the jacks magic purple. It is easy to find and affordable. Would you have a recommendation for a maintenance dose with the purple stuff. The bottle states weekly, several post state monthly, and the pool builder says every 3 months add one 32oz bottle ???? My pool is 15,000 gal SWG with plaster. Thanks again. A humble thank you to you.
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Phosphates algae and copper

Postby chem geek » Tue 13 Nov, 2007 21:54

You are most welcome. We're all here to help.

Don't use any pool chemical you don't need. So with Jack's Magic to sequester metals, I wouldn't use it in maintenance mode unless you have fill water that is high in metals. It's better to periodically get the water tested for metals or test your fill water for metals and figure out roughly how much sequestrant you need. You don't want to just add more and more if you don't need to -- the same advice is true for most any of the chemicals -- you want enough to be effective as needed, but not more than that.

PolyQuat 60 dosages for pools have been roughly worked out to prevent algae so their maintenance mode is reasonable since it breaks down over time and it mostly gets trapped in the filter with consolidated particles since it is also a clarifier. Phosphate removers also specify a maintenance mode, but here is a case where you really need to see what your phosphate level is over time and only add more remover when you need it -- otherwise you're just spending extra money faster.

Richard
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Phosphates algae and copper

Postby hoodfigga » Sat 17 Nov, 2007 07:46

In closing I would like to ask one more question and please try not to laugh out loud. After using the pr-3000 (phosphate remover) and the seaklear algea remover / treatment my pool filter pressure went from 12lbs to almost 30lbs. I have cleaned the filter 3 times with a hose and the pressure has lowered to about 25lbs. If I clean the filter thoroughly or replace the filter, am I removing or negating any of the anti-algae / anti-phosphate treatment out of the pool system.
On a side note I found the taylor test kits k-2006 at a great price with low shipping at SPS swimming pool supply company here.
I have not dealt with them before so I will post my experience at a later time.
I thank you again!!
15000GAL / Diamond Brite Classic / Aquarite SWG / 1.5hp Strarite / Hayward C17502 Cartridge Filter / AquaCal 155A Heat Pump /Sunny South Florida
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Phosphates in pool water

Postby chem geek » Sat 17 Nov, 2007 14:20

I don't know the answer to your question as I don't know why the pressure went up. Perhaps the algaecide was like PolyQuat and is a clarifier so algae got consolidated and caught in the filter. If that is the case, you want to clean the filter and remove such dead algae -- otherwise, it will just be something that uses up chlorine trying to break it down.

Thanks for the new source of the K-2006 at a great price. Just keep in mind that the tftestkits(dot)com link is for a kit that has 36% more volume in the reagents so you need to factor that in when doing price comparisons.

Richard
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Phosphates in pool water

Postby mr_clean » Sat 17 Nov, 2007 17:51

After using the pr-3000 (phosphate remover) and the seaklear algea remover / treatment my pool filter pressure went from 12lbs to almost 30lbs. I have cleaned the filter 3 times with a hose and the pressure has lowered to about 25lbs. If I clean the filter thoroughly or replace the filter, am I removing or negating any of the anti-algae / anti-phosphate treatment out of the pool system.


no, as it has been used up fighting the problem you had & this would be why you would need more for the future.
I'm guess you have cartridge filter sense you state you have to spray it off to clean. You can buy new one if in bad shape or buy cleaner you can soak cartridge in which will help deep clean it.
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Postby hoodfigga » Sat 08 Dec, 2007 07:28

Hello all. Happy Holidays. First I would like to say that I received my Taylor 2006 test kit from Iowa Pool and Spa. The test kit was priced very well with a fair shipping price. Best of all the kits are being shipped directly from Taylor Industries. I figure the kits are new and fresh. Just to let you know I am not a employee of the above company. Just sharing my thoughts.

Using a quality test kit is the way to go. No more guessing and its a plus or should I say a must to compare your results to the pool store. I only wish they would make a ph test that had a definite color change like the chlorine. I really have a hard time seeing those shades of color. A word of advice from a newbie pool owner to another newbie. Spend the money and buy the test kits suggested in the forums. Buying the basic test kits leave you guessing. The Taylor instruction manual inside the test kit is very educational as well.

As far as testing the water at the local pool stores I think i hit the jackpot at a mom and pop store. They test water, build pools and provide maintenance as well. Just when I thought I had it all figured out they test my water and give my a Alkalinity result with correction. Here we go again I said to myself. Corrected Alkalinity what the heck. Turns out after some research you should correct your total alkalinity numbers by a percentage of your cya reading to get a true alkalinity number. Am I right. I hope so because I thought my alkalinity was 100 but they corrected it to a much lower number.
So now I need bicarbonate right. Well the gentleman at the pool store hands my this 5 pound hefty freezer bag with this fine white powder inside. My first thought was ScarFace. It turns out they sell most of their products in bulk. Basically they bag up the same products their maintenance guys use on the field and sell it to the public. Quite a savings compared to the commercial containers that they sell at Pinch a Penny or Leslie's. I do have one question about the pool acid they sell. They use sulfuric acid. The container claims it has low odor and fumes, and it does. That muriatic acid got me few times real good right in the lungs. I tried to do some research but I really could not find a reason for using sulfuric acid vs Muriatic acid. Any thoughts??

Now to cleaning the filter. I have seen suggestions in the forum on cleaning the filter with a solution of cascade and water in a extended soak. Well my filter is really huge and we have water restrictions and I could not justify using so much water to soak a filter. The pool store sells filter cleaning solutions in spray bottles so I figured I would make my own. I took a tablespoon of cascade and placed it in a 32oz. spray bottle and mixed it with water and sprayed down the filter. I let it soak for awhile and hosed it off very well. Viola my water pressure went from 30psi to about 11 psi. It dropped so much I removed the filter cartridge and inspected if for a hole or tear. Anyways thats what I did any comments would be appreciated.

Lastly I started using a pool blanket in the winter months trying to collect heat and save some penny's on the heat pump bill. What can I expect as far as chemical water changes. More chlorine , less chlorine, acid, alk, what effect does covering the water have on the pool chemistry. If you have any links please provide them.

Happy Holidays and thank you for your time once again. In closing my eggnog quote of the day.
"What was was and what is is. Today is what it is. Don't worry about the what ifs and live the what is"
15000GAL / Diamond Brite Classic / Aquarite SWG / 1.5hp Strarite / Hayward C17502 Cartridge Filter / AquaCal 155A Heat Pump /Sunny South Florida
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Phosphates in pool water

Postby chem geek » Sat 08 Dec, 2007 14:14

hoodfigga wrote:Just when I thought I had it all figured out they test my water and give my a Alkalinity result with correction. Here we go again I said to myself. Corrected Alkalinity what the heck. Turns out after some research you should correct your total alkalinity numbers by a percentage of your cya reading to get a true alkalinity number. Am I right. I hope so because I thought my alkalinity was 100 but they corrected it to a much lower number.
So now I need bicarbonate right.

I do have one question about the pool acid they sell. They use sulfuric acid. The container claims it has low odor and fumes, and it does. That muriatic acid got me few times real good right in the lungs. I tried to do some research but I really could not find a reason for using sulfuric acid vs Muriatic acid. Any thoughts??

Lastly I started using a pool blanket in the winter months trying to collect heat and save some penny's on the heat pump bill. What can I expect as far as chemical water changes. More chlorine , less chlorine, acid, alk, what effect does covering the water have on the pool chemistry. If you have any links please provide them.

The adjustment for Total Alkalinity ONLY applies to the calculation for the saturation index, not as an isolated number by itself (as far as "ideal ranges" is concerned -- such ranges having already taken into account the CYA normal range). You can always have a higher Calcium Hardness and/or pH to compensate for a lower TA. An absolute number, even adjusted, is not that useful. I doubt very much that you needed to increase your TA. A higher TA will often lead to a tendency for the pool to rise in pH over time due to the increased outgassing of carbon dioxide (TA is mostly carbonates making a pool essentially over-carbonated, like a lovely tasty beverage!). If you post a full set of numbers (FC, CC, pH, TA, CH, CYA, Temp), then I can give you more info.

I would use Muriatic Acid instead of Sulfuric Acid. Sulfuric Acid results in an increase in sulfates whereas Muriatic Acid results in an increase in chloride (salt). The sulfates aren't bad, but in higher concentrations may cause some problems though this is not definitive, but I'd rather just avoid that issue entirely. As for the fuming of Muriatic Acid, you can either just use it making sure you are upwind from it or hold your breath (or breath turned away) or use a lower fuming Muriatic Acid -- you can get half-strength that doesn't fume as much, but you need to use more and it costs almost the same. You won't be adding acid that often (or shouldn't be) so if you want to use the Sulfuric Acid you've already bought, that's fine.

It sounds like you've hit upon a reasonable method for cleaning your filter.

The main change with a pool blanket is less evaporation of the water and protection of the chlorine from breakdown from sunlight. So fill water amounts should drop and chlorine usage should drop, though in the winter it drops anyway due to lower temperatures. One thing you might notice is that the pH rises as the water temperature lowers ( from around 7.5 to 7.8 ) and that is normal even if the pool is covered.

Richard
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Phosphates in pool water

Postby hoodfigga » Mon 10 Dec, 2007 06:25

Ok here are my numbers. Its a little late on the bicarbonate. I already added it to the pool.

FC 4
CC 0.5
pH 7.6
TA 120
CH 320
CYA 80
Temp 78

When I did my CYA test using the taylor 2006 it seems that the disappearing black dot is very subjective. The pool store tested my cya at 80 and I would say the dot disappeared at that point. If I had not had a predetermined number in my head, I wonder what I would have chosen as my cya reading. If you have any tips on reading the black dot please share them with me.

Thank you
15000GAL / Diamond Brite Classic / Aquarite SWG / 1.5hp Strarite / Hayward C17502 Cartridge Filter / AquaCal 155A Heat Pump /Sunny South Florida
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Phosphates in pool water

Postby chem geek » Mon 10 Dec, 2007 13:58

Well, when you run your SWG, you will probably find a rather strong tendency for the pH to rise because the TA is at 120 ppm. That's too bad they had you raise it so high. It only makes sense to have a high TA when using an acidic source of chlorine such as Trichlor. The SWG produces hydrogen gas bubbles at one of its plates (it produces chlorine gas at the other plate and that dissolves in water) and these hydrogen gas bubbles strongly aerate the water pulling the carbon dioxide out of the water and into the air. That causes the pH to rise.

So a lower TA level helps reduce the problem since TA is a measure (at least partly) of the amount of carbonates in the water. A pool is over-carbonated like a beverage (though not as much, obviously) and just like stirring up a beverage or blowing bubbles in it through a straw makes it go flat, an SWG also makes it "go flat" and the pH rises as a result.

There is a LOT that pool stores do not know. The fact that a higher TA leads to a faster rise in pH is one of them. The fact that a high CYA level leads to algae growth unless a higher FC is maintained is another. By the way, at your pool's 80 ppm CYA, you should have an absolute minimum FC of 3.6 ppm at all times and I'd set it to 4 ppm FC to be safe. In a manually dosed pool, the minimum would be 6 ppm, but an SWG seems to do OK at a lower level, probably due to the superchlorination of the water that goes through the SWG cell. This all assumes you don't use an algaecide (e.g. PolyQuat 60) or a phosphate remover. You can always spend more money with regular use of an algaecide or phosphate remover and then use a lower chlorine level, but just keep in mind that chlorine alone can keep away algae -- that is, you don't have to spend more on these other products unless you want to. They are more like insurance in case the chlorine level drops too low.

There is another alternative for helping to reduce algae growth and that is to add 20 Mule Team Borax (plus acid since the Borax increases pH) to get to 50 ppm Borates. These act as an additional pH buffer and also as an algaecide, though not as powerful as PolyQuat 60. That lets you cut down the SWG output as less chlorine is needed to prevent algae growth. The use of a phosphate remover has a similar effect -- lots of options, but some are more expensive than others (using chlorine alone is least expensive, then Borates, then PolyQuat 60 and finally phosphate removers).

This post describes the procedure for lowering the TA if you find that you need to add acid frequently to keep the pH down. Essentially this procedure just accelerates the process that your pool will be going through compressing months into days. At your pool's 80 ppm CYA level, you could target a TA as low as 70 ppm though you can lower the TA to 80 ppm and see how it goes. Right now, your pool is actually slightly over-saturated with calcium carbonate (the saturation index is +0.14) and with an SWG you want to be a little under-saturated because scale has a tendency to build up on the SWG plates (even with auto-reversing polarity, though that certainly helps reduce the problem). That's something else this pool store apparently was not aware of -- though they certainly were ready to sell you an Alkalinity increaser.

By the way, they basically just sold you Arm & Hammer Baking Soda which is Sodium Bicarbonate. So you should compare the price of what they sold you to what you can buy in a grocery store or Costco for a large box of Baking Soda. Is their "bulk" price really a good deal (you can generally get Baking Soda for around $1 per pound or less if you search the web $18-$20 for 24 1-pound boxes)? If this pool store were giving you good advice, then paying more for chemicals would be worth it, but so far I don't see where they have been really helping you -- yes, the phosphate remover is a quick (and expensive and profitable) way to get rid of algae (using a copper algaecide does that as well, but with side effects from the extra copper), but they haven't told you why you got the algae in the first place (too low an FC for your CYA level) and gave you incorrect advice regarding the TA level which may now be too high.

Richard
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Minimun Phosphate Levels ??

Postby AprilZer » Thu 04 Jun, 2009 05:24

Now I know it .,Thanks for sharing you ideas I am so glad that I am a member of this site.,


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