Hot Tub Forum
Original => Hot Tub Forum => Topic started by: Quickbeam on July 12, 2014, 12:50:44 pm
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I just recently did my first water change and would like to get some advice re balancing my water.
My numbers are as follows:
PH - 7.6
TA - 30
CH - 130
I know that my TA is low, but it needs to be at 30 for my PH to stay stable during aeration. My TA was also at 30 during my initial fill. Given the numbers above, my Saturation Index is just under -0.5 (our hot tub is at 101 degrees), which puts my water out of balance. I could raise my PH to 7.8 which would bring me in balance, but I’m wondering if I really need to, as I am thinking a PH of 7.6 is a pretty good number. I remember in a previous post that Chemgeek had said that with an acrylic shell tub with no exposed plaster or grout there is no real need for having the CSI be near zero. So my real question is, should I leave my PH at 7.6, or should I add some borax and try and bring the PH up to 7.8?
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Nothing wrong with what your doing, but I think your over thinking it.. Bring the alk up a bit and call it good, give it a few days and see where it goes..
It's more me than you, so please don't take that wrong..
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You don't need to worry about the saturation index if your spa is acrylic and you have no plaster or grout exposed to the water. Also, it would be better to have a higher pH target such as 7.8 with a higher TA target (40 or 50) if you can still have the pH be reasonably stable there (you can see from this link (http://richardfalk.home.comcast.net/~richardfalk/pool/CO2.htm) that the over-carbonation should be fairly similar). With a low TA you have to be VERY careful not to use net acidic chemicals in the water that would use up the TA or else your pH will crash.
Are you using 50 ppm borates (usually from boric acid)? That will provide more pH buffering given that your TA is low. It especially helps slow down the rate of pH rise. You don't want to misjudge your aeration and end up with the pH very high which can then cause calcium carbonate scaling (though with your low TA the risk for that is fairly low).
I presume you are using the Dichlor-then-bleach method, correct? Keep in mind that Dichlor is net acidic and for every 10 ppm FC it will lower the TA (after chlorine usage/consumption) by 3.5 ppm. So if you use Dichlor for 40 ppm to add 36 ppm CYA to the water, then the TA will drop by 14.1 ppm. That's another reason to start out a little higher in TA.
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Thanks Jacuzzi Jim and Chemgeek for the responses. I have found with a TA any greater than 30 my PH shoots up with any significant aeration in the tub. Unless I’m missing something, I don’t think I can have my TA any higher than 30. As for borates, yes, I am using 50 ppm from boric acid. As for my sanitizer, I’m using hydrogen peroxide. I know that’s not the normal way to sanitize but so far we really like it.
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OK that's fine. Hydrogen peroxide breaks down into water and oxygen gas and when reacting with nitrogenous compounds produces water and nitrogen gas so is pH neutral. For proper disinfection, the hydrogen peroxide level should be around 100 ppm but that is a level some people find to be irritating. Hydrogen peroxide is not an EPA-approved disinfectant, but it is approved by the APVMA in Australia where you can see this label (http://websvr.infopest.com.au/LabelRouter?LabelType=L&ProductCode=68642) requiring (100/850)*598 = 70 mg/L to (250/1500)*598 = 100 mg/L and this label (http://websvr.infopest.com.au/LabelRouter?LabelType=L&ProductCode=62939) stating a minimum 100 ppm level to be maintained and this label (http://websvr.infopest.com.au/LabelRouter?LabelType=L&ProductCode=39380) (for pools) requiring 100 ppm and never going below 40 ppm.
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Thanks Chemgeek,
So do you think I should leave the PH at 7.6 or should I try bumping it up to 7.8, or does it not matter?
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If your pH is stable at 7.6 you can leave it there. Though it doesn't matter, you might as well be closer to the 7.5 midpoint of the pH test giving you ample warning if the pH drifts from there too much.
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Thanks Chemgeek!
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I don't have my tub yet but I ask the Jacuzzi dealer about different sanitizers and when I mentioned hydrogen peroxide he told me it would void my warranty , Jacuzzi claims (don't know if its true or not but its their tub till the warrant runs out ) that hydrogen peroxide dries out the seals and causes leaks down the road after time.....
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I don't have my tub yet but I ask the Jacuzzi dealer about different sanitizers and when I mentioned hydrogen peroxide he told me it would void my warranty , Jacuzzi claims (don't know if its true or not but its their tub till the warrant runs out ) that hydrogen peroxide dries out the seals and causes leaks down the road after time.....
Hog wash, dealer can sell what they want as far as chems. Might be in the small print somewhere I have just never read it. But they do use the same gaskets or made of the same material anyway as everybody else so it would probably be fine.
Least in my book I would cover it and not look for an excuse as to why something failed and push it back to the consumer for a reason not to cover it.
All that said I would not use hydrogen peroxide as a sanitizer.
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I don't have my tub yet but I ask the Jacuzzi dealer about different sanitizers and when I mentioned hydrogen peroxide he told me it would void my warranty , Jacuzzi claims (don't know if its true or not but its their tub till the warrant runs out ) that hydrogen peroxide dries out the seals and causes leaks down the road after time.....
Hog wash, dealer can sell what they want as far as chems. Might be in the small print somewhere I have just never read it. But they do use the same gaskets or made of the same material anyway as everybody else so it would probably be fine.
Least in my book I would cover it and not look for an excuse as to why something failed and push it back to the consumer for a reason not to cover it.
All that said I would not use hydrogen peroxide as a sanitizer.
He was just telling me Jacuzzis position on the matter , knowing this guy , he would cover it if I dumped gasoline in there ......his concern was problems down the road AFTER the warranty period if leaks start poping up......I wasn't going that route anyway even though its probably fine......
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We just recently purchased a Jacuzzi 345 and before we bought I specifically asked the dealer about warranty coverage. He went to Jacuzzi and came back and told us that Jacuzzi would discourage the use of hydrogen peroxide but if we did use it our warranty would not be affected. It was only on that basis that we purchased from Jacuzzi, as before we purchased any tub we had our mind made up we were going to use hydrogen peroxide.
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As for hydrogen peroxide wear on hot tub components, see this post (http://www.whatsthebest-hottub.com/forum/index.php/topic,12161.msg152860.html#msg152860), this post (http://www.whatsthebest-hottub.com/forum/index.php/topic,6726.msg79439.html#msg79439), and these posts (http://www.whatsthebest-hottub.com/forum/index.php/topic,4543.msg52326.html#msg52326). Also, this manual (http://www.dynastyspas.com/downloads/SwimSpaManual.pdf) ("Please avoid using any spa chemicals that contain Hydrogen Peroxide. Hydrogen Peroxide based spa chemicals have been found to react adversely with the materials used to produce these components.") and this manual (http://www.alpsspas.com/wp-content/uploads/downloads/2013/04/Alps_Owners_XLS_Manual.pdf) ("Alps Spas strongly discourages the use of chemicals that contain Hydrogen Peroxide. Hydrogen peroxide will eventually cause the light body and lenses (used on all spas) to become brittle and crack.").
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As for hydrogen peroxide wear on hot tub components, see this post (http://www.whatsthebest-hottub.com/forum/index.php/topic,12161.msg152860.html#msg152860), this post (http://www.whatsthebest-hottub.com/forum/index.php/topic,6726.msg79439.html#msg79439), and these posts (http://www.whatsthebest-hottub.com/forum/index.php/topic,4543.msg52326.html#msg52326). Also, this manual (http://www.dynastyspas.com/downloads/SwimSpaManual.pdf) ("Please avoid using any spa chemicals that contain Hydrogen Peroxide. Hydrogen Peroxide based spa chemicals have been found to react adversely with the materials used to produce these components.") and this manual (http://www.alpsspas.com/wp-content/uploads/downloads/2013/04/Alps_Owners_XLS_Manual.pdf) ("Alps Spas strongly discourages the use of chemicals that contain Hydrogen Peroxide. Hydrogen peroxide will eventually cause the light body and lenses (used on all spas) to become brittle and crack.").
glad I read those , but I don't think I was going to try it anyway ( no way I am now ) but that was my guys take on it mostly , makes things "brittle" over time (who needs that ?) hard on seals and the problems wouldn't show up until the warranty period was over ......again , I don't know if its true or not but im not chancing it.....maybe people that ARE using it can update on it after at least 3 to 5 years of use and see if there were any side effects ?
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Thanks Jacuzzi Jim and Chemgeek for the responses. I have found with a TA any greater than 30 my PH shoots up with any significant aeration in the tub. Unless I’m missing something, I don’t think I can have my TA any higher than 30. As for borates, yes, I am using 50 ppm from boric acid. As for my sanitizer, I’m using hydrogen peroxide. I know that’s not the normal way to sanitize but so far we really like it.
What is aeration to you? Are you referring to effervescence, little bubbles popping off the surface of the water???
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No, I'm talking about having the jets on full with the air control to the jets turned on. Waterfall also going.
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As for hydrogen peroxide wear on hot tub components, see this post (http://www.whatsthebest-hottub.com/forum/index.php/topic,12161.msg152860.html#msg152860), this post (http://www.whatsthebest-hottub.com/forum/index.php/topic,6726.msg79439.html#msg79439), and these posts (http://www.whatsthebest-hottub.com/forum/index.php/topic,4543.msg52326.html#msg52326). Also, this manual (http://www.dynastyspas.com/downloads/SwimSpaManual.pdf) ("Please avoid using any spa chemicals that contain Hydrogen Peroxide. Hydrogen Peroxide based spa chemicals have been found to react adversely with the materials used to produce these components.") and this manual (http://www.alpsspas.com/wp-content/uploads/downloads/2013/04/Alps_Owners_XLS_Manual.pdf) ("Alps Spas strongly discourages the use of chemicals that contain Hydrogen Peroxide. Hydrogen peroxide will eventually cause the light body and lenses (used on all spas) to become brittle and crack.").
glad I read those , but I don't think I was going to try it anyway ( no way I am now ) but that was my guys take on it mostly , makes things "brittle" over time (who needs that ?) hard on seals and the problems wouldn't show up until the warranty period was over ......again , I don't know if its true or not but im not chancing it.....maybe people that ARE using it can update on it after at least 3 to 5 years of use and see if there were any side effects ?
As I said we are using hydrogen peroxide and will continue to do so, although I must admit I’m not thrilled with the information that Chemgeek provided. I really don’t need those kind of problems in my tub. Having said all that, the main reason we started using hydrogen peroxide is that my wife has some pretty serious chemical sensitivities and we just didn’t want to chance either chlorine or bromine. After having used it for a while now, we love it. No chemical smell, no dry skin, skin feels almost smooth or moisturized after a soak. For us so far, it is a great alternative.
If I remember I will keep you updated on any significant equipment problems that are related to the use of the hydrogen peroxide. We do have a friend who has been using it for some time now without any problems. Not sure exactly how long they have used it, but I will check with her and report back.
One other thing that may come into this. It seems to me that there is a kind of trend with people who use hydrogen peroxide that they do nothing else to take care of their water. I’ve seen a blog re hydrogen peroxide in hot tubs and from what I could tell, there was no other water maintenance being employed. I know our friend who uses it does nothing else to take care of her water. I’m wondering if this is a trend with hydrogen peroxide users, if this could be one of the factors contributing to equipment failure???
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.....I know that my TA is low, but it needs to be at 30 for my PH to stay stable during aeration. My TA was also at 30 during my initial fill.....
.....glad I read those , but I don't think I was going to try it anyway ( no way I am now ) but that was my guys take on it mostly , makes things "brittle" over time (who needs that ?) hard on seals and the problems wouldn't show up until the warranty period was over ......again , I don't know if its true or not but im not chancing it.....maybe people that ARE using it can update on it after at least 3 to 5 years of use and see if there were any side effects ?
.....As I said we are using hydrogen peroxide.... and will continue to do so.....the main reason we started using hydrogen peroxide is that my wife has some pretty serious chemical sensitivities and we just didn’t want to chance either chlorine or bromine. After having used it for a while now, we love it. No chemical smell, no dry skin, skin feels almost smooth or moisturized after a soak. For us so far, it is a great alternative.
Quickbeam, There are always 2 side to any coin, and as for consequences, only time will tell the truth.
What I don't understand is why you feel compelled to keep your alkalinity low when it needs to be in the 80-120 range, your pH is elevated, and yet you're willing to take it higher to 7.8.....after you made a reference in a recent post, "no chemical smell, no dry skin, skin feels almost smooth or moisturized", which means you are familiar with these conditions. Your skin is pH neutral in the 7.2 to 7.6 range, higher, or lower, will give you dry skin, and females will avoid it. As for alkalinity being out of range, it needs to be adjusted first, as pH will not stabilize and stay where it belongs until alkalinity is in the proper range. Adjust your alkalinity first, THEN, adjust pH up or down as necessary, and it will stabilize.
When you smell, ding, ding, ding, your "smeller tester" is going off, indicating attention is needed. I know that time has past, but if your pH is not 7.2 to 7.6, and your alkalinity is not in the 80 - 120 range, you will have water problems, and gas off the water (the smell).
Unless the water is right on, the ladies loose interest, us guy's, what do we care, we will sit in battery acid as long as we have a beer, but ladies are different. We are dealing with water chemistry here and everything is said to be able to provide results, but as you can see, there are 2 sides to every coin.
Have you considered using ozone on your spa?
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us guy's, what do we care, we will sit in battery acid as long as we have a beer,
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There IS truth on the internet !......can I use that as my sig?
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us guy's, what do we care, we will sit in battery acid as long as we have a beer,
[/b]
There IS truth on the internet !......can I use that as my sig?
I would be glad to share it with you, I've got many more. ;)
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.....I know that my TA is low, but it needs to be at 30 for my PH to stay stable during aeration. My TA was also at 30 during my initial fill.....
.....glad I read those , but I don't think I was going to try it anyway ( no way I am now ) but that was my guys take on it mostly , makes things "brittle" over time (who needs that ?) hard on seals and the problems wouldn't show up until the warranty period was over ......again , I don't know if its true or not but im not chancing it.....maybe people that ARE using it can update on it after at least 3 to 5 years of use and see if there were any side effects ?
.....As I said we are using hydrogen peroxide.... and will continue to do so.....the main reason we started using hydrogen peroxide is that my wife has some pretty serious chemical sensitivities and we just didn’t want to chance either chlorine or bromine. After having used it for a while now, we love it. No chemical smell, no dry skin, skin feels almost smooth or moisturized after a soak. For us so far, it is a great alternative.
Quickbeam, There are always 2 side to any coin, and as for consequences, only time will tell the truth.
What I don't understand is why you feel compelled to keep your alkalinity low when it needs to be in the 80-120 range, your pH is elevated, and yet you're willing to take it higher to 7.8.....after you made a reference in a recent post, "no chemical smell, no dry skin, skin feels almost smooth or moisturized", which means you are familiar with these conditions. Your skin is pH neutral in the 7.2 to 7.6 range, higher, or lower, will give you dry skin, and females will avoid it. As for alkalinity being out of range, it needs to be adjusted first, as pH will not stabilize and stay where it belongs until alkalinity is in the proper range. Adjust your alkalinity first, THEN, adjust pH up or down as necessary, and it will stabilize.
When you smell, ding, ding, ding, your "smeller tester" is going off, indicating attention is needed. I know that time has past, but if your pH is not 7.2 to 7.6, and your alkalinity is not in the 80 - 120 range, you will have water problems, and gas off the water (the smell).
Unless the water is right on, the ladies loose interest, us guy's, what do we care, we will sit in battery acid as long as we have a beer, but ladies are different. We are dealing with water chemistry here and everything is said to be able to provide results, but as you can see, there are 2 sides to every coin.
Have you considered using ozone on your spa?
Sorry Clover, I’m not really sure I understand your post. I don’t feel compelled to keep my TA low. My PH will not remain stable unless my TA is low. If my TA is anything above 30 my PH shoots up when I aerate the tub.
As for adjusting the alkalinity first, that is exactly what I’m doing. The correct procedure, as I understand it, is to add acid (in my case I’m using dry acid), then aerate the tub, and check your readings. The more dry acid you add, the lower the TA. My problem is that when I aerate the tub with a TA above 30, my PH shoots up. There are others on this board who have had similar experiences.
Once my TA is at 30, the PH becomes stable. I could at this point add some borax to slightly increase my PH, while leaving the TA at 30. This was my original question as to whether or not I should do this, so my water would be in balance according to the Saturation Index. With my numbers, if my PH was 7.8, I would be in balance according to the Saturation Index. Chemgeek has advised that I don’t need to bother adjusting my PH, so for now I’ll leave the PH at 7.6.
As for a “smell testâ€, my water has never had any kind of foreign smell and has always been crystal clear. I’m a new tub owner, but at least so far my water has been excellent. The only problem I’ve had is that the PH will not stabilize until my TA is very low, which once again I know others on this board have experienced.
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What I don't understand is why you feel compelled to keep your alkalinity low when it needs to be in the 80-120 range, your pH is elevated, and yet you're willing to take it higher to 7.8.....after you made a reference in a recent post, "no chemical smell, no dry skin, skin feels almost smooth or moisturized", which means you are familiar with these conditions. Your skin is pH neutral in the 7.2 to 7.6 range, higher, or lower, will give you dry skin, and females will avoid it. As for alkalinity being out of range, it needs to be adjusted first, as pH will not stabilize and stay where it belongs until alkalinity is in the proper range. Adjust your alkalinity first, THEN, adjust pH up or down as necessary, and it will stabilize.
When you smell, ding, ding, ding, your "smeller tester" is going off, indicating attention is needed. I know that time has past, but if your pH is not 7.2 to 7.6, and your alkalinity is not in the 80 - 120 range, you will have water problems, and gas off the water (the smell).
There is so much that is wrong here I hardly know where to begin. First of all, skin is NOT pH neutral in the 7.2 to 7.6 range. The pH of skin is normally acidic in the 5.4 to 5.9 (or 4.5 to 6.0) range (see this paper (http://www.ncbi.nlm.nih.gov/pubmed/3700100) and this paper (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC227028/)). Perhaps you are thinking of the pH of human tears which average 7.50 in this paper (http://www.ncbi.nlm.nih.gov/pubmed/9154387) or 7.0 in this paper (http://www.ncbi.nlm.nih.gov/pubmed/7469869).
It is absolutely positively not true that you set your TA to a range such as 80-120 ppm and that the pH will then stabilize anywhere near the range of 7.2 to 7.6 that you desire. This will only occur if you are using net acidic chemicals in the spa such as Dichlor for chlorine or bromine tabs for bromine or MPS non-chlorine shock and even then it depends on how much aeration there is in the spa. If instead you are using net pH neutral chemicals (which includes the pH that results from their usage/consumption), then the pH will rise from the high TA since the water is over-carbonated which increases carbon dioxide outgassing (the TA does not change from such outgassing; the TA only drops when you later add acid to lower the pH). Increased aeration of the spa water will increase the rate of carbon dioxide outgassing and therefore the rate of pH rise. The amount of over-carbonation of water with respect to air is shown in this chart (http://richardfalk.home.comcast.net/~richardfalk/pool/CO2.htm). TA is mostly a measure of bicarbonate in the water and that is in equilibrium with carbon dioxide in the water. The equilibrium pH at various carbonate alkalinity levels (same as TA if there is no CYA nor borates in the water) is as follows where I also show the pH where water has 2x the amount of carbon dioxide compared to air (at 100ºF water temp):
Carb.Alk. . pHeq . pH2x
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.... 10 ...... 7.55 ... 7.25
.... 20 ...... 7.84 ... 7.55
.... 30 ...... 8.02 ... 7.72
.... 40 ...... 8.14 ... 7.85
.... 50 ...... 8.23 ... 7.94
.... 60 ...... 8.30 ... 8.02
.... 70 ...... 8.37 ... 8.08
.... 80 ...... 8.42 ... 8.14
.. 100 ...... 8.51 ... 8.23
.. 120 ...... 8.58 ... 8.30
.. 140 ...... 8.64 ... 8.36
So with lots and lots of aeration to increase the surface area between air and water to drive out carbon dioxide faster, your 80 ppm TA would have the pH rise and only reach equilibrium at 8.42. In practice, the rate of pH rise slows down considerably as one approaches equilibrium but even 2x out of equilibrium (i.e. twice as much carbon dioxide in the water as there would be with equilibrium in the air) is a pH of 8.14. You can see that at a TA of 30 ppm the equilibrium pH is 8.02 with a 2x equilibrium pH of 7.72. This is why having a TA of 30 works much better for Quickbeam and indeed in general those using other pH neutral methods such as after switching to bleach when using Dichlor-then-bleach should not have their TA be higher than 50 ppm.
Acrylic spas with no exposed plaster or grout do not need to be saturated with calcium carbonate which is the primary reason for having higher TA and CH. The main reason for the 80-120 ppm TA standard recommendation (which is really more for pools than for spas) is that one normally uses net acidic chemicals so having the carbon dioxide outgassing helps to compensate for that to stabilize the pH. As for pH buffering itself to minimize the swing in pH from any chemical sources, one can use additional non-carbonate pH buffers when their TA is low such as using 50 ppm Borates (some people use phosphate buffers as "pH lock", but that precipitates calcium so can be messy initially).
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Thanks Chemgeek,
For another in depth explanation. I do however have a couple of novice questions for you. I have been balancing my water before adding my sanitizer. Is this the correct method, or should I start by adding the sanitizer, or does it matter? And as for adding the boric acid, I have been adding this after my TA is down to 30 and my PH has stabilized. I'm assuming this is the correct sequence?
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In your situation since hydrogen peroxide addition is essentially pH neutral, you can balance before adding the hydrogen peroxide. Obviously you don't want to wait too long (many hours) since you don't want bacteria to grow when there is no disinfectant but odds are your tap water has a disinfectant in it already.
Yes, you usually want to add the boric acid after lowering the TA. If you do this the other way around, then this makes it harder to know the TA lowering process is working because you won't see the pH rise as quickly as an indicator to you for when to add more acid. Also, when you are at the end of the process with the TA where you want, you then want to aerate to get the pH up but that will also take longer when the borates are present. It's not a disaster to do it this way, but it can be more confusing or frustrating.
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Makes sense! Thanks Chemgeek.