Nitro's Guide to Water Maintenance

[Nitro]

I have this guide posted on other boards. It seems to be very popular, so I thought I'd post it here. I hope it helps you to maintain your tub water a little easier.

[size=16]Introduction[/size]
There are two main things to consider when maintaining your hot tub water, Water Balance and Sanitation. There are a few different methods to sanitize your hot tub, Bromine and Chlorine being the most popular.  The method in this writeup is based on Chem Geek's famous Dichlor/Bleach method. However, Water Balance is related to all sanitation methods, so this could be helpful to anyone.

I will assume you have a fresh fill of water in your tub. If you don't and you're having problems, or it's close to the time to refill, you're better off just refilling your tub and starting over. Hot tub water should be changed every 3-5 months depending on usage. However, if your tub has serious problems, or you bought a used tub etc., you may want to decontaminate your tub.

In order to really maintain your water properly you need to test it. Test strips are ok for getting rough estimates, but IMO will make it more difficult to maintain your tub. It would be difficult for me to keep my tub as well tuned as it is by just using test strips. For a novice, I can see it being really difficult, especially if you have Well Water. Do yourself a favor and get a Drop Test kit such as the Taylor K-2006.

One more note. Before I got my hot tub, I knew nothing about water chemistry. After I started studying hot tub water chemistry, I realized there was a lot more to keeping a hot tub water safe then I anticipated. However, after learning it, I realized it doesn't have to be difficult or time consuming. This may get a little technical, but once you learn it, you'll have no trouble keeping your water balanced/sanitized.

Here we go:

[Nitro]

[size=16]Water Balance[/size]
Water can be either Acidic, Balanced or Alkaline. If your water is not balanced, it could cause all kinds of problems. If it's too Acidic it could cause corrosion. If it's too Alkaline it could cause scaling. Both of which will reducing the effectiveness of your sanitizer. If your water is not balanced your water is not safe for you, or your tub. So it's really critical to get this correct.

There are four main parameters to keeping your water balanced. Water Temperature, Calcium Hardness (CH), Total Alkalinity (TA) and Potens Hydrogen (pH). Assuming your water temp is around 100 degrees, we'll just focus on CH, TA and pH. The best way to test these is with a Drop Test kit, like the one mentioned above. IMO Test Strips are just not accurate enough to test these, especially for a beginner.

Calcium Hardness: CH is basically the amount of Calcium in your water. The lower your CH, the higher your TA and pH need to be to have balanced water. The higher your CH, the lower your TA and pH need to be. The first thing you should do is test your CH in your tub. If you haven't filled your tub yet, test your tap water for CH using a drop test kit. If you have a water softener in your house, it will remove most of the Calcium in your water. That means you may get a different reading from your indoor sink then from the outdoor hose. Check both to make sure. If you have really bad well water i.e. lots of metals etc., you may want to fill your tub using the water softener water, then just add Calcium afterward. If your water is city treated water, you may be ok straight from the hose. Also, consider getting a pre-filter that attaches to your hose, and filters out some of the metals.

Here's my recommendation. If your CH is much below 100 ppm, you should add calcium to bring it up to 130-150 range. If your CH is over 100, you can leave it alone and just make a note of what it is. The CH level will be used to determine your TA/pH levels. To raise Calcium you add Calcium Chloride, aka Calcium Increaser. You can find it at most Pool/Spa supply stores. The good news is you only need to add Calcium once per water change, because it will stay relatively the same until your next water change.

Potens Hydrogen: pH is the measure of acidity in your water. It's on a scale of 0 to 14, 7 being neutral. The human eye has a pH of 7.5, so the ideal range in Pools/Spas is 7.4-7.6 with a min of 7.2 and max of 7.8. However, and this is important, just because you have a pH of 7.5, doesn't mean your water is balanced. If your CH is too low, you could be corroding your hot tub heater. If your TA is too high, you could be forming scale in your tub. Both of which will reduce your sanitizer effectiveness. So it is very important to have balanced water along with an ideal pH.

[Nitro]

[size=16]Water Balance Part 2[/size]

Total Alkalinity: Alkalinity is a pH Buffer. High levels of TA will not allow pH to change from additions of acid or base. However, a high TA requires a low pH to have balanced water. On the other hand, very low levels of TA will allow the pH to change with very little acid. A very low TA level could cause your pH to drop to low levels, very fast with little acid. Also, the lower your TA, the higher your pH needs to be to have balanced water. So as you can see, a very low TA can become very unstable.

However, pH will have a tenancy to rise with aeration (i.e. use of jets and air), more so if your TA is high. Although, as long as you're not adding Acid (or anything with a lower pH) to your tub, the pH will not usually drop. Therefore, in hot tubs the problem is normally pH rise (or Drift), because of all the aeration. So the trick is to get the TA high enough to not create an unstable situation, and low enough to not allow pH to rise too much.

Let me repeat the last sentence, because it's the single most important thing to keeping your water balanced. The key to having balanced water, without pH drift, is having the correct TA level. If you find your pH rises too high (>8.0) after using your tub, your TA is too high, and needs to be lowered. If you find your pH is too low and/or your water is continually acidic, your TA is too low and needs to be raised. By fine tuning your TA, you can get your pH perfectly balanced, that rarely needs adjustment.

SO, what's a good TA then? That sort of depends on your CH. If your CH is around 150 ppm, your TA would need to be 80 ppm for your water to be balanced with an ideal pH of 7.6. How did I come up with those numbers you ask? Easy, I went to The Pool Calculator website, and plugged in a Temp of 100, CH of 150, pH of 7.6 and adjusted TA until the CSI was close to zero. This website allows you to calculate your Saturation Index, based on the four Main parameters, Temp, CH, TA and pH. If CSI is less than zero your acidic, if it's greater than zero your alkaline and of it's close to zero your balanced. The CSI dosen't need to be exactly zero, +/- 0.3 is good enough.

OK, how do we adjust TA then? If TA is too low, you just add Baking Soda to raise it. However, if TA is high, it's little more involved. You'll need Acid (Dry or Muriatic). Depending on how high your TA is will depend on how long it will take you. Plan on it taking around an hour to decrease TA by 100 ppm. So if your TA is 300 ppm, plan it taking around 2-3 hours. First, uncover your tub and turn on all your jets, air, blowers, waterfalls etc. Test your pH. When it's greater than 7.8, add enough acid to bring it down to 7.0. Keep aerating until your pH is 7.8 again (about 30 min), then add more acid and repeat. Every time you add acid you're lowering your pH and TA. When you get your TA tuned perfectly, your pH will rise to a level (i.e. ~7.6) and stop, then you know you're at your ideal TA level. If your pH is rising too high (>8.0), bring your TA down a little more. If your pH doesn't rise enough from aeration (after an hour or more), you over shot it and need to add a little Baking Soda to raise your TA. After a few days/weeks of monitoring it, you'll get your TA tuned perfectly. You may need to add a little Dry Acid once a week or two, but your water should be well balanced at that point.

I wouldn't lower TA much below 50 ppm, because that could become unstable if you add any kind of acid. Also, if you have a very high TA, above 200, you may need to add more acid in the beginning to get your pH down. Remember, TA is a pH buffer, so the higher the TA, the more acid it takes to bring the pH down. It takes approximately 8 oz total of Dry Acid to bring TA down 100 ppm in a 350 Gal tub. However, the important thing is not to add too much acid all at once, causing your pH to drop below 7.0. That's why you should divide up the dosages, while aerating constantly. While using bleach you will fine a TA of 50-60 ppm is ideal for keeping pH in check. However, if you lower your TA to 50-60, you may need to raise CH to compensate.

There is one more thing I haven't mentioned that you can add to your tub that will help buffer your pH, Borates. The easiest way to add Borates to your tub is to get a product called Gentle Spa. It is pH balanced, so there is no need to add acid to counter balance it. The ideal amount is ~50 ppm, and only needs to be added once per water change. That will help keep your pH from drifting from aeration. Not to mention, actually make your water feel silkier. I highly recommend it.

BTW, I'm purposely not giving the exact amounts of Calcium, Baking Soda or Acid to use, because The Pool Calculator will calculate that all for you. Just enter your tub size at the top, enter the current level in the left column, then enter your goal amount in the right. It will tell you the amount and what you need to add. For instance, if you enter tub size of 320 gal, a pH of 7.8 in the left column and 7.0 in the right, it calculates .4 oz or 2 tbs of Dry Acid. All you need to balance your water perfectly is Calcium Chloride, Baking Soda, Dry Acid and The Pool Calculator.

[Nitro]

[size=16]Sanitation[/size]
I'm only going to discuss Chlorine here. This is based on Chem Geeks Dichlor/Bleach method. I have found this method to be very easy and safe to use. I have yet to have a problem. I don't want to get into pros and cons, because that's better suited for it's own thread. If you don't know his method, this should explain it to you. If you do know it, maybe this will help you execute it better. I'm not going to get too technical. I'm just going to discuss everything that's important to keep your tub sanitized easily. If you want more details, search through Chem Geek's posts. You'll have plenty to read. Disclaimer: I'm not trying to convince you to use this method. I'm just explaining it. Please weigh all options before making a decision.

There are really two main things happening when your pool/tub is being sanitized. Organic waste is being oxidized, and bacteria/viruses are being killed. Chlorine does both, very well. That's why it's the most popular sanitizer in pools and spas. However, in order for chlorine to be effective there needs to be a Free Chlorine (FC) level in your tub at all times. If it drops to zero, bacteria will multiple within hours. So the number one rule with using chlorine as a sanitizer is, never let it drop to Zero for any length of time. Now lets get started on the procedure.

The first thing we are going to use to sanitize our tub is Dichlor. Dichlor is actually two things, Chlorine and Cyanuric Acid (CYA). CYA is a chlorine stabilizer, which slows down dissipation from UV rays (sunlight). It also acts as a buffer to hold chlorine in reserve. Having CYA in your tub will stop the chlorine from dissipating as fast while waiting for something to do. However, CYA also cuts down on the ability for the chlorine to sanitize. So in other words, the higher the CYA level, the longer the FC will wait in the tub, but the less effective the FC is. With no CYA in the tub, using bleach would be too strong and not practical to use. So, there needs to be a happy medium. Luckily Chem Geek has come up with one for us. He suggests a CYA of ~20 ppm. Personally I use a CYA of 30 ppm for reasons I won't get into here. But I think Chem Geek would agree anywhere between 20-30 is fine. Where the problem comes in is when CYA gets too high (above 100) after weeks of using Dichlor. Then your FC needs to be really high to get the same sanitation effectiveness. That's why we switch to bleach after we get our CYA to 20-30. Bleach doesn't add anymore CYA.

So, I'm going to assume our target CYA is 30, but feel free to use 20 and adjust as necessary. I find that it's easier to keep track of how much Dichlor you're adding to the tub and calculate the CYA, rather than testing CYA with the drop test kit until you get a 30 ppm reading. For every 10 ppm of Dichlor you add to your tub, you add 9 ppm CYA. So roughly 34 ppm Dichlor will give you 30 CYA. On a fresh fill, and after your water is balanced by the above method, shock your tub with Dichlor to 10 ppm FC. Then over the course of the next days, depending on bather load, add 24 ppm more FC using Dichlor. You want to keep your FC normally between 3-6 ppm everyday. This means you will be testing your FC EVERYDAY.

For example: On one day you test your FC and it's 1 ppm. You'll then add 5 ppm FC to bring it to 6. The next day you test FC and it's 3. You then add 3 ppm FC. You will do this until you add a total of 34 ppm FC to your tub using Dichlor. After that, you then switch to using bleach (Clorox Regular Unscented). Important: if you're not willing to test your tub everyday, at least for the first month or two, this method is not for you. I'd recommend another sanitation method

[Nitro]

[size=16]Sanitation Part 2[/size]

When you use your tub (this applies to when you are still using Dichlor or after you switch to bleach), the rule of thumb is, you'll use approximately 7 ppm FC per person per hour in a 350 gal tub. Now this will depend on a lot of things, water temp, cleanliness of the users etc. If it's just two people, after taking showers, using no swimsuits, with the temp at 98 you may only need 2 ppm FC/person/hour. However, if you have 6 people in their clothes, drinking (spilling) beer, with a temp at 102 causing everyone to sweat, you may need 20 ppm FC/person/hour. So this is where you may need to make a judgment call and/or experiment. Remember, the Chlorine has to do two things, Oxidize Waste, and Kill Bacteria. If your tub is being subjected to a lot of waste (sweat, beer etc), your FC will be used up and not be able to kill bacteria. Not good! So I'll give you two scenarios and how you might go about running an experiment. Remember, all this up front work is only necessary in the beginning, until you learn how much FC is being used in your tub. Once you know, it becomes easy to maintain. The rule of thumb is, assuming CYA is 20-30 ppm, FC should normally be between 3-6, with a min of 1 and shock to 12 once a week.

We'll go with the easy one first, two people, showered, no suits etc. (Note: Some people prefer to use the tub with very little FC. That's your choice. I'm just telling you how to determine how much FC you're using in a safe manner). Test your FC and add Chlorine to get to 5 ppm FC. After one hour of soaking test FC again. If you find you have no FC after an hour, next time start with 6 or 7. If you find you still have 3 ppm FC, next time it's safe to start with 3-4 ppm FC. Get it? The trick is to have the lowest amount of FC without ever dropping to zero. If you plan on staying in the tub longer than an hour, either start out with more FC, or add some during the soak. However, you don't want to get into the tub with the FC much above 8, unless of course you like a strong smell of chlorine. I got in once with FC at 10, and it was a little too much for me, and I like the smell of Chlorine.

On the other extreme. Full tub of people drinking, sweating etc. Do the same as above, but start out with more FC, maybe 6-8 ppm. Check the FC in an hour (or even a half). If you have no FC, you need to add some and check more often. If you still have FC, add some, and check again in the same time frame. It's the same as above, but you're just using more FC, more often. However, having the FC drop to zero for a short time with your lover, is not the same as with 4-5 other people, if you get my drift. So it's much more important to keep FC above zero at all times during a Hot Tub Party.

If you find you're having trouble keeping FC in your tub during party's, and/or you smell a foul odor during your soaks, you can add Potassium Monopersulfate (MPS or Non-Chlorine Shock) before (and/or during) your soak to help the Chlorine Oxidize waste. The only thing I would say is, go easy with MPS. Use only the amount needed and not much more. It is acidic and will lower your TA/pH if you use a lot. Start out with 1-2 tbs in addition to your normal FC, and see if that cuts down on the FC usage. Up it to 3-4 tbs, or add another 1-2 tbs during the soak if needed. MPS will help oxidize waste. However, it will not kill bacteria, so you still need FC. Also, you can use MPS as a shock once a week to help oxidize leftover waste, and reduce Combined Chlorine (spent FC).

After a month or two you will learn a routine, and be able to add Chlorine less often (i.e. every 2-3 days). How often you need to add Chlorine will depend on your Chlorine Demand (CD). The lower the CD, the less often you need to add Chlorine. The key is to keep CD as low as possible. HERE is a link that describes Chlorine Demand in detail, how to measure it and how to keep it low.

[Nitro]

Wow if you made it this far, you did pretty good. It seems like a lot to learn, but it's really not. I'll summarize it here.

[size=16]Summary[/size]

Water Balance

• If your CH is much below 100 ppm, raise it to ~150 ppm. Otherwise, make a note of it.
• Adjust your TA to ~60 ppm to start with then fine tune from there. Use Baking Soda to raise it, or Acid/Aeration method to lower it. It takes ~8 oz Dry Acid to lower TA by 100 ppm in a 350 Gal Tub. Don't add all at once! If you lower your TA, you may need to raise your CH to compensate.
• pH should be between 7.2-7.8. Aerate to Raise pH. Acid to lower it.
• If pH creeps up too much (>8.0), lower TA. If pH is to low, and doesn't raise enough by aeration, raise TA.
• Add ~50 ppm Borate. (Borox/Acid or Gentle Spa)
• Calcium, Baking Soda, Dry Acid and Borates is all you need to balance your water.
• Use The Pool Calculator to calculate exact amounts to add.

Sanitation

• On a fresh fill use Dichlor until you get to 20-30 ppm CYA. (10 ppm FC = 9 ppm CYA)
• Then switch to Clorox Unscented 6% bleach.
• Never let FC drop to Zero for any length of time. Keep it between 3-6 ppm normally, min of 1 ppm, and shock to 12 ppm once a week.
• Use MPS if needed before hot tub party's and/or once a week to help oxidation. Go easy, because it's acidic and will lower your TA/pH.
• Check your Chlorine Demand often, and keep it low.
• Dichlor, Bleach and MPS is all you need to keep your tub sanitized.
• Use The Pool Calculator to calculate exact amounts to add.

Lastly, get a drop test kit such as the Taylor K-2006. Also get FC test strips, because they come in handy for a quick estimate, during party's etc. The only two things you need to check regularly are FC and pH. Check them everyday and after soaks. If you have your water well balanced, you'll rarely need to adjust your TA. Shock once a week, and/or after high bather loads. Use MPS if you have party's, and/or don't want to use as much chlorine. Keep Chlorine Demand low, and you'll only need to add Chlorine every 2-3 days and after soaks. Easy as can be, and your tub is always ready.

I hope that helps you to understand Water Maintenance a little better.

Happy tubbing!  

[Nitro]

Reserved

[Spatech_tuo]

Reserved

That would be fine to give to people whose job it is to explain water care to spa owners but it won't work for the actual average spa user due to length and a feeling that they're having to read a dry text book. In fact I've seen similar postings by people but I can't even attempt to read this because I'm tired from staying up too late last night and doubt I could get past the second paragraph without needing a nap (water care theory does that to me). I'll wait for the movie.

Hmm, maybe I should post my method and name it after myself, "Spatech's simple guide to water care"! If I did I know it would be about 80% shorter in length, 5 or 6 bullet point sentences and a couple small paragraphs at most. I wonder how I'd collect royalties. Maybe I could combine it with my theories on dating and gambling?

[Nitro]

That would be fine to give to people whose job it is to explain water care to spa owners but it won't work for the actual average spa user due to length and a feeling that they're having to read a dry text book. In fact I've seen similar postings by people but I can't even attempt to read this because I'm tired from staying up too late last night and doubt I could get past the second paragraph without needing a nap (water care theory does that to me). I'll wait for the movie.

Hmm, maybe I should post my method and name it after myself, "Spatech's simple guide to water care"! If I did I know it would be about 80% shorter in length, 5 or 6 bullet point sentences and a couple small paragraphs at most. I wonder how I'd collect royalties. Maybe I could combine it with my theories on dating and gambling?

I'm just trying to cover all the bases for beginners. There's always the Summary at the end for people who want to skip the details.

[COWBOY]

Why don't you post your guide spatech . I am a beginer & would like to see it. Also does anyone have a suggestion were to purchase a Taylor K-2006 kit.

[Nitro]

Hi Cowboy, you can get the kit HERE for $55. If anyone knows a cheaper/better source, let us know.

[COWBOY]

Next question? How long does the kit last or maybe i should ask how many tests do you get from a kit?

[In Canada eh]

Hmm, maybe I should post my method and name it after myself, "Spatech's simple guide to water care"! If I did I know it would be about 80% shorter in length, 5 or 6 bullet point sentences and a couple small paragraphs at most. I wonder how I'd collect royalties. Maybe I could combine it with my theories on dating and gambling?

I've always preferred my Thursday, Saturday, Sunday approach

[Nitro]

Cowboy, that's a good question. I'm not sure how many tests you'll get in the kit. That depends on the measurements. As far as how long the kit will last, you can expect the FC, TA and pH tests to last a few months in the beginning. This is because you will be testing often. However, once you get the hang of it you won't be testing as much, and can expect them to last 6 months or more. As far as the CYA and CH, they should last at least 6 months or more. You can also buy 2 oz reagents, that will last a lot longer, and be a bit cheaper per test.

[Chas]

I usually tell people this: pH and TA should go up and down together. Add Spa Down if they are too high, Spa Up if they are too low.

Add a tablespoon of dichlor after every use.

Test the chlorine level daily for the first few weeks, and adjust the amount of chlorine you add after use until you have it so that there is JUST a readable chlorine level when you next go to use the spa.

Change the water every three or four months.

Do NOT test pH and TA more than once a week, and do NOT retest pH and TA sooner than 6 hours after adding Up or Down.

And testing for pH and TA with a high chlorine content is useless.

 8-)