Phosphates.....are they worth removing??

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Yeah, Matt's messing with me because he knows my phosphate level makes PHOSpool a living thing...darned near the po4 rate of blood ;)

My pool is natural enough without further shenanigans. Just had to rescue an idiot chipmunk as I was typing that.

Re: pbtc...I know your suspicious of MM's comparative staying power ;) Me too. But don't they have to specify in the msds?
 
Swampwoman said:
Yeah, Matt's messing with me because he knows my phosphate level makes PHOSpool a living thing...darned near the po4 rate of blood ;)

My pool is natural enough without further shenanigans. Just had to rescue an idiot chipmunk as I was typing that.

Re: pbtc...I know your suspicious of MM's comparative staying power ;) Me too. But don't they have to specify in the msds?
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I believe half your pool is HEDP .... literally, your pool is half water, half HEDP ???

I'd stake the chipmunk corpse up on a pole as a message to all other chipmunks to stay away....but, knowing those nasty creatures, they'd probably just eat it..?

Corporations are allowed to claim trade secret / proprietary formulation status (even if the components are trivial) on anything they produce as long as the components are not an acute hazard. The only person that could request an exact formulation would be emergency personnel (like a doctor) and they'd have to sign an NDA before the info was released.

I can do a snooty British accent and pretend to be a doctor....?
 
I'd stake the chipmunk corpse up on a pole as a message to all other chipmunks to stay away....but, knowing those nasty creatures, they'd probably just eat it..��
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Yeah, it was his buddy who pushed him in...he's alive and well and digging up my terrace as we speak. They drive me crazy but I can't let em drown.

MM's msd cites this: 1-Hydroxyethane-1,1- diphosphonic acid 2809-21-4
30 to 40% - so, HEDP.

What would something with pbtc say?
 
Swampwoman said:
Yeah, it was his buddy who pushed him in...he's alive and well and digging up my terrace as we speak. They drive me crazy but I can't let em drown.

MM's msd cites this: 1-Hydroxyethane-1,1- diphosphonic acid 2809-21-4
30 to 40% - so, HEDP.

What would something with pbtc say?
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Some friend, no honor among squirrels or thieves!! Good thing to rescue it as it could have ripped your liner with its claws trying to get out.

PBTC = Phosphonobutane-1,2,4-Tricarboxylic acid

http://downloads.hindawi.com/journals/bca/2005/546865.pdf
 
Ok, the discussion is starting to get sidetracked again slightly. Let’s try to pull it back in again.


JoyfulNoise, going back to the comment made back on the 2nd.

SWG 40% all season
Pump run time ~ 6 hours for SWG active --> 2.4 hrs/day FC production or 2.2ppm FC loss
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What did you keep your SWG at before you reduced your phosphates? What was your pumps run time? Lastly, what was your CYA level??
 
Leebo said:
Ok, the discussion is starting to get sidetracked again slightly. Let’s try to pull it back in again.


JoyfulNoise, going back to the comment made back on the 2nd.



What did you keep your SWG at before you reduced your phosphates? What was your pumps run time? Lastly, what was your CYA level??
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Going back to my paper notebook for the 2015 swim season (sadly, The PoolMath App did not exist back then :( ), I typically ran my SWG at 40-50%, my pumps would run 8-10 hrs/day and my CYA was about 80ppm. I also added quite a bit of bleach manually to "bump up" my FC. This was all done to maintain my FC in the 6-8ppm. So if you compare chlorine production time, on the lowest end (40% and 8 hours back in 2015), I was running my sanitation system 33% longer back then...and I was adding bleach to my pool regularly (probably once every 10 days or so).

Could I have up'ed my SWG output and not bothered with manual bleach additions, sure. I like to run my SWG on the low side because I want to stretch it's life as much as possible. For my pool equipment (Pentair), the replacement cells are a huge cost, about twice what one would pay for a Hayward cell. So getting as much life as possible out of them is really important to me. Looking at my current situation, by running at a lower FC I run my cell less and that leads to less wear & tear on it which dovetails nicely with my goal of extending cell life as long as possible. Knock-on-wood, when I need to replace my current cell, my next cell will be an IC60 so that I can get the most life out of it possible and not have to run it very long to achieve my desired FC levels.
 
Swampwoman said:
Hi Matt. Swamp-hubby reports 15 ppm nitrate, 0 nitrite.
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Wow. That's low but your water is new. My nitrates are above 80ppm (water is 4+ years old).

Nitrites will react a lot like ammonia, if the FC is measurable, then those two will always be zero.
 
Given your high phosphates and low nitrates, your Redfield ratio in the pool is quite low, much less than 10. That puts you more at risk of developing blue-green algae (which is a bacteria) than standard green algae.

You should go chlorine-free and throw some Koi in the pool, they'd love it!!!
 

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Yeah, I just looked up the math on the Redfield and while math is not my strong suit, I see that given the ratio is mols that my ratio right now is .91:1.

Last year in this thread I believe we'd mused about my bucket test where it took more than a week to develop any algae at all...on the face, surprising given the high po4...at that time I think you or Auspool had wondered about a limiting effect of high po4 levels.

So this ratio supports that notion and gives a logical explanation ;)

The larger meaning for pool owners on well with metals may be that po4 reduction, at least blindly to the no3 : po4 ratio, could actually make them more susceptible to green algae, as crazy as the sounds ;) Some well owners will have much higher nitrates...so I'd expect this to vary wildly from user to user.

Which makes it all feel a bit like winking in the dark ;)
 
Bucket tests for algae aren't very good indicators. A bucket full of pool water is highly sanitized and will, if left on its own, take a very long time for any algae to form. If one wanted to do a bucket test, it would take several buckets (and control samples) with different kinds of water in it (pool water with and without FC, bottled water, distilled water with and without fertilizer added, etc) and then you'd need to inoculate each with a very small dose of algae. The way to test it would be to use a turbidity meter (kind of like those expensive CYA meters) to measure the amount of cloudiness caused by the multiplying algae over time. You'd also need to maintain consistent temperatures as well as ensure good, indirect light exposure (not too much UV). My bet would be that if you took RO distilled water (pure H2O with nothing in it), it would be just as hard for algae to grow in that water as it would in sanitized pool water.

OR

You can just throw a nice big handful of fertilizer in your pool and see how easy it is to maintain the water.... ;)

By the way, many thanks to Mark for correcting my poor math skills - in my previous post I had stated that my daily FC loss was 2.2ppm when in fact, that is just how many ounces of chlorine gas my pool uses (based on SWG generation rates and pump run times). 2.2 ounces of chlorine gas equates to 1ppm FC lost per day. So my actual daily FC loss rate is around 1ppm per day.

I guess since I use so little chlorine, I should probably just switch over to Baquacil.... :laughblue:
 
UPDATE: Phosphate-Related Scale in Heat Exchanger of 1 Year Old Heater

So, per earlier posts, my heater works fine but produces tuquoise/white and black flakes that test when ground up to be a ratio of 10 parts po4 to 3.5 parts copper to 2.5 parts iron. I don't know if there's also zinc in there (plated zinc can be blue) but it doesn't fizz so if there's any calcium, its not much. My ch is 190.

Today I had a Raypak authorized heater pool tech with 40 years experience out to inspect the heat exchanger before putting up dome for winter (his family owns the pool const and service company. He is in my books highly competent.)

And we have stumped him ;)

1. The scale shed is def coming from the heater, not the swg
2. The cupronickel tubes do not appear corroded, nor is there evidence of ridging
3. However, in two of the return side tubes, there was a buildup of something scale-like that was partially clogging the tube
4. The intake side tubes were clean
5. The unitherm governor had the same buildup, which may have been interfering with regulation. Its a cheap part so he replaced it for maintenance purposes.
6. The heater guts look otherwise brand new.

Here are pictures of the heat exchanger.

My pet theory is that my high po4 levels are enacting chemgeek's phosphate scale formula, causing excessive coating, but that for some reason its not "sticking" at least, uniformly, to the tubes and therefore they still transfer heat.

The takeaway is that I may need to consider po4 removal (ongoing) to preserve heater or alternately, plan annual heat exchanger maintenance, or possibly both.

PS...He also feels Raypak is off-base requiring a check valve with swg because "it can't possibly produce chlorine unless its under flow." Pretty much verbatim Joyful's comment ;) That said, he installed one with a flow meter so that should any warrantied failure occur, we've complied with the new installation instructions ;)

image.jpgimage.jpgimage.jpg
 
Need to know if there's zinc in that scale. Did you keep a sample of it? I'll see if I can figure out a test for zinc...I'll have to blow the dust off my copy of Vogel's Quantitative Chemistry ... assuming I can locate the cardboard moving box it's stuffed in....

I say you pull that Zn anode out and see if the scaling stops.
 
So here's A theory - the heavy use of phosphonates in your pool is controlling iron stains BUT it is also contributing to copper corrosion and scaling. You can search Google with terms like "phosphonates" and "copper" and what you'll find is many different technical articles and some of them will state quite explicitly that copper corrosion (removal of copper ions from the surface of copper metal) is enhanced or increased when phosphonates are present. This makes a lot of sense because phosphonates like AMP and HEDP make the 2+ metal cations (Ca2+, Fe2+, Cu2+, etc) much more soluble in water than they would otherwise be. So, while the HEDP is doing a bang up job keeping your iron in solution, it is also increasing the rate of dissolution of anything copper submerged in it. It also probably enhancing the solubility of the Zn anode because zinc always forms Zn2+ cations in solution.

As JamesW has pointed out, the higher temperatures in the heater are probably causing the copper and residual phosphate anions to scale out as copper phosphate. Here's something to try - if you have any concentrated ammonia around, try to add some of that blue scale to ammonia (the more concentrated, the better). Copper phosphate isn't soluble in water but it is soluble in ammonium hydroxide.

You're Raypack dude is very wise (and not because he totally agrees with me on the uselessness of a check-valve ;) ), you may need to control your phosphate levels whether you like it or not....

....or learn some Zen techniques from Bob and just live with lots of ugly brown stains all over your liner....or, hijack and Evian truck and fill your pool with bottled water.....
 
Need to know if there's zinc in that scale. Did you keep a sample of it? I'll see if I can figure out a test for zinc..
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Yessir, I did, because I KNEW you'd have some mad sciencing afoot ;)

I was also feeling prescient last week and bought a bottle of ammonia.
However, working later nights this week, so it may not be until the weekend til I experiment ;)

I like HEDP because it actually works. But among my options would be floccing the dickens out of PHOSpool and switching to EDTA. BUT the voice of ChemGeek haunts me:
Not only are the EDTA sequestrants not as effective in terms of binding to metal ions, but they tend to break down more quickly from chlorine, to the point where you can even notice an increased chlorine demand having them in your pool and need to use larger maintenance doses than with HEDP.
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So another option is to pay a couple hundred a year to clean out the exchanger until such time I have to shell out about $850 for cupro nickel bundle or $550 for copper bundle. Nuke the buildup po4 with a gallon of commercial lanathum chloride, then maintain monthly and dust off chemgeek's Calc on the po4 vs temp vs ch vs ph ratio required to stay under scale production. This is my most likely course.

And/or consider installing an iron curtain on line to outdoor spigot (about the cost of a new heater.) Or maybe try oxygen injection.

Given my high heat and rate of evaporation, I probably "add"/swap in the neighborhood of 40-50 inches of water a year or more, so hijacking a water truck just wouldn't cut it ;)

After all, we're now just 1 year out from my $1000, complete water change...and here I am mucking about with HEDP, phosphate scale, and such ;)
 
Heat pump with a titanium heat exchanger would be immune to HEDP/PO4 issues.....in the winter you might need two heat pumps with a wood burning stove nearby to provide the excess heat ?
 

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