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We suggest to all of the folks we go see (if they use us or not) to buy a good quality test kit (I'll use the Taylor K2006 as an example here) and use it. We like the K2006 for its ability to test chlorine accurately (up to 50 ppm), and the customer is able to take full control of their water if they use this tool.
How sad to think that this same customer could go buy test strips (which I find highly inaccurate) and maintain their pool, yet I try and point these same folks in the right direction with a quality test kit and quality water, but I could end up being sued if I took one component "too low". I envision much greater damage being done with chemicals and overall bad pool maintenance than 150 CH!
I completely understand David’s perspective. He is advising to avoid (if possible) being blamed for any kind of plaster issue, even falsely blamed. That is good advice. That is reality.
But let’s understand a couple of things. The NPC’s guidelines are NOT industry accepted standards. The APSP Standards ARE the industry accepted standards, and service techs can cite them when they need to when defending themselves against false attacks.
The NPC’s recommendations or guidelines are restrictive, unfair, with no scientific basis. And yes, they are being used to victimize service techs unfairly. Our industry should ban together and take steps to put pressure on the NPC to change their ways and stop this nonsense.
I also want to respond to David’s reference, "”Pool Surfaces, Problems and Solutions, Techlines - 7th Edition" by Randy Dukes. As quoted in David's earlier comment, the book states that, "Prolonged calcium levels below 200 ppm can create an aggressive deteriorating condition." I would suggest that statement is only true when the overall SI is significantly aggressive, not in isolation only. Therefore, I consider that statement misleading.
The book also recommends the calcium level to remain low (below 175 ppm) for the first month on new plaster startups, yet, the plaster is most vulnerable during the first month. The fact is that well cured plaster (after one month) is more resistant to aggressive water than new fresh plaster.
On page 96, it says that adding 5 gallons of acid per 10,000 gallons of water will improve the appearance of an “improperly” hydrated (discolored) pool. And if that doesn’t work, then add another 5 gallons of acid! So adding that much acid is okay? But a calcium level around 150 ppm is bad for the plaster?
Lastly, the pool industry is being harmed by misinformation and false accusations. This type of behavior by plasterers also helps the “underground” (bad plasterers) stay in business doing poor work. Pool owners will end up choosing alternatives surfaces, such as vinyl or fiberglass, or not get a pool in the first place.
David, you make a good point, but I am sure you would agree that it should not be that way for service techs - and it is not right.
There are standards that are accepted within the industry (like them or not... agree with them or not)
Most plaster installers require a minimum of 200 CH.
I am not sure it is worth it to provide pool water that is outside these parameters, unless you are willing to buy the client a new plaster job occasionally. If something happens and the plaster somehow gets ruined, and the water is tested and it is discovered that the CH is lower than 200, you are going to get blamed -- Even though it likely has nothing to do with the CH of the water! -- and you will either share in the cost of a replaster, or you will be replastering the pool on your own dime. A plasterer will walk away from pool that is damaged if he can prove that the chemical balance is out of spec. And in a court of law, all they look at are the standards... There are no special Swimming Pool specific courts where all the lawyers and jury members are familiar with the nuances of pool water chemistry. All they will ask is: "What are the industry standards, and who was responsible for the pool that did not FULLY comply with those standards?"
I am looking at this more from a legal perspective, not as much from a chemistry perspective... I have seen lawsuits happen to others, and it really doesn't matter who was actually wrong, it matters more who has good insurance, and who the blame can be pinned on the easiest, and in my opinion that could be you if you deliver the client water that is not balanced to the industry accepted standards.
As Richard stated (of which I agree), is that if the carbonate alkalinity and pH are high enough to offset a low calcium level as calculated by the SI, then the water is not aggressive. It is the Saturation Index that is the determining factor to this issue, not a single low parameter within the Index. I have performed several experiments that have shown this to be true (the subject of a future blog).
Where I disagree with Richard, is that there are some good reasons to lower the calcium to its lower range. A lower calcium level can offset a high alkalinity and high pH. Of course, one can lower the last two easily, but when using hypochlorite sources (as Richard mentioned), lower calcium levels can be helpful to avoid scaling a pool. Also, maintaining a continuous positive SI can result in scale and staining. Therefore a temporary negative SI can undue this effect.
Let's not forget that Bruce is rectifying a high calcium issue, and many pools are scaled as he mentioned in another post forum.
Yes, there are service personnel that don’t know about the SI. But they can make mistakes on both sides of water balance, not just the aggressive side. They can just as easily scale a pool. Bruce, I am sure you could leave good instructions for the pool owners or the service guy to follow after you perform your service. That would help with liability.
I just wish more service people would realize that a slightly negative SI (-0.3) does not create the problems that some NPC plastering members claim it does. Don’t allow them to get away with convincing you that a calcium level of 150 ppm is AUTOMATICALLY aggressive and detrimental. They have no evidence of that. Yet, there is evidence that water with only 150 ppm of calcium can still be balanced, and an occasional -0.3 SI is not detrimental.
What plasterers need to do is to always produce a quality product. And when they do, their plaster job will hold up to rigors of what it was meant to do in the first place. Service techs and plasterers know that a good plaster job can last over 20 years, even with moderately variable water chemistry.
Again, the only reason that I have considered that number is to provide an "extra" to help the customer. I can easily hit the 200 ppm mark, but my thinking is that lower CH allows a margin of error, so to speak, for any Calcium that would come back into solution.
My motivation is to assist the customer,not run my machine longer. If I am not providing anything of additional value at a lower ppm level, then I will provide the 200 ppm value and feel good that I have done my job. Do we agree?
You usually don't need to get as low as 150 ppm CH except in spas and that's an entirely different animal (due to higher temperature and lots of aeration that tends to make the pH rise unless the TA is kept lower). Since the 200 ppm CH is in the range that the plaster guys want, there's not much reason to go lower. If the TA is very high, then it will likely need to get lowered anyway and you'll do that by removing bicarbonate along with everything else via your RO process.
The codes are the codes... We may not agree with them, and there are many that are just flat wrong (like the CA requirement for sweep 90's in pool plumbing!! --- I digress) BUT we all must still abide by them, because they are what governs our industry.
I totally get what you are trying to do, and think its honorable... I just think that pushing the limits of the code is potentially dangerous... Do I think that 150 will cause problems? Probably not, BUT you are still opening yourself up to potential liability.
I have my opinions... and you have yours... and that's cool! I'm not trying to force my opinion on anyone... just sharing it for discussion sake. The beauty of America, and owning our own businesses, is that we can all make our own decisions... It's why I love what I do, and could not ever imagine working in a corporate setting!
Bruce Wettstein said:
Since our water is so hard straight from the tap, my thinking is that if I take it a little lower than "recommended", then I give folks a little more time before they have to have the service again. I know that sounds odd from a business standpoint, since we all want and appreciate repeat business, but I think it would be nice to give folks a little more time before treatments. How nice would it be if we could go just a little bit farther before out next oil change? Or haircut?
I appreciate all of your input. I'm just trying to do the right thing, and I certainly don't need to cause damage while trying to be helpful!
I don't see anywhere that 150 is an acceptable level.
Plus like I said in my original post... You can't count on the poolman using the saturation index to maintain balanced water! Half of the poolmen that I see don't even use a test block... They simply drop a few drops of Soln. 2 into the water and "add acid as needed". I would venture to say that better than 50% (I'd guess even upwards of 75%) of our industry has ABSOLUTELY NO CLUE what the saturation index even is, let alone how to measure it!!
We always think about the "bonehead" serviceman, and plan accordingly on our projects... This is not to say that there aren't good poolmen out there, BUT you have to prepare for the bad ones...
Kim Skinner said:
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