new hot tub owner with questions about managing the water

[md1870]

I got my first hot tub this past summer and have found the water management challenging. I have several questions. Please let me know if there is a better place to post this. I see a water care forum here, but it seems to have little activity, so I'm thinking it makes more sense to post here.

As brief background, I have a Jacuzzi J345. I looked at various brands, and I had by far the best experience with the Jacuzzi dealer in the area (Raleigh area). I have been very happy with the hot tub itself. Good size for a hot tub that will be used the vast majority of the time by 1-2 people but is comfortable for 4. I'm very glad of where I decided to locate it. It's very easy to use it since it's convenient to the back door. This isn't a cold climate by any means, but it's cold enough often enough that I wouldn't want it farther from the door. 

OK, on to several water care questions. I appreciate any input from those who understand how to do it well, and hopefully relatively simply. 

(1) I find it difficult to read the test strips. They usually vary a good bit if I do multiple readings back-to-back, even with the same brand. A bigger issue is that I find it difficult to visually differentiate the levels. I'm not colorblind, but the differences in shade are very subtle to me, and so for example the color shade for one level below the ideal range to on level above doesn't seem very different to me at all. I've tried three test strip brands, and they all seem this way to me. I would prefer a device that gives a digital reading, but I looked into that a little and the reviews didn't seem great, with many people saying they get quite different readings on back-to-back readings with the device. It seems like it's essential to have an accurate starting reading if I'm going to manage my water well, so please advise on how best to do this. 

(2) Is there an accepted/recognized resource that provides good information on how much of each chemical is needed to adjust the water based on the how much change is needed and the amount of water? Mine is about 350 gallons. I see a lot of advice to "add some of chemical X and re-check the reading in Y hours." I'd much rather be able to add an amount of a given chemical based on how much it should be, such as add Z amount of sodium bisulfate if I need to lower the alkalinity by 100 units for a 350-gallon volume.

(3) Are there clear guidelines on which water chemicals can be added simultaneously, versus which need to be done at different times? For example, can I add something to adjust water hardness, something to adjust alkalinity, and also add chlorine all at the same time? If not, how much time is needed between adding different types of chemicals? Also, how much time needs to pass before any added chemicals would be expected to show most of their effect, so the water could be re-tested?

(4) So far I have only left the cover open after adding chlorine (dichlor), leaving it open for 30 minutes. Otherwise I close the cover immediately after adding anything. Does it need to be left open for any other chemicals? Whenever I add anything I run two of my four jets for a 20-minute cycle. 

(5) My hot tub has an ozone system. My understanding is this should be responsible for most of the decontamination, and therefore much less chlorine is needed. However, it also means the chlorine reading is extremely low unless I have added chlorine very recently. How do I know whether I'm adding the right amount of chlorine? 

Thanks for any feedback. I'm really enjoying my hot tub but really struggling with this aspect of it. 

[cranbiz]

Dump the strips, they are inaccurate. Buy something like a Taylor test kit with reagents.

When using dichlor, you need to monitor the CYA. It should be about 30PPM. Once you hit 30PPM, switch to liquid chlorine bleach. Keep your TA around 125PPM.  I run my PH around 7.5  Once you get your CH right, it shouldn't change unless you add more water.

[ratchett]

On 3/19/2023 at 2:14 PM, md1870 said:

(1) I find it difficult to read the test strips. They usually vary a good bit if I do multiple readings back-to-back, even with the same brand. A bigger issue is that I find it difficult to visually differentiate the levels. I'm not colorblind, but the differences in shade are very subtle to me, and so for example the color shade for one level below the ideal range to on level above doesn't seem very different to me at all. I've tried three test strip brands, and they all seem this way to me. I would prefer a device that gives a digital reading, but I looked into that a little and the reviews didn't seem great, with many people saying they get quite different readings on back-to-back readings with the device. It seems like it's essential to have an accurate starting reading if I'm going to manage my water well, so please advise on how best to do this. 

As Cranbiz mentioned - test strips are terrible.   A titration drop test kit is easier to read and provides more reliable accurate test results.   Test strips can actually go bad over time (or when exposed to moisture/humidity) and provide inaccurate readings

 

On 3/19/2023 at 2:14 PM, md1870 said:

(2) Is there an accepted/recognized resource that provides good information on how much of each chemical is needed to adjust the water based on the how much change is needed and the amount of water? Mine is about 350 gallons. I see a lot of advice to "add some of chemical X and re-check the reading in Y hours." I'd much rather be able to add an amount of a given chemical based on how much it should be, such as add Z amount of sodium bisulfate if I need to lower the alkalinity by 100 units for a 350-gallon volume.

There are many different care routines - not everyone uses the same care routine.  Long ago I heard that one person in a hot tub requires roughly the same amount of sanitizer as 50-100 people in a pool!  It's crazy how much more sanitizer is needed due to the hot water being an ideal breeding ground for bacteria. 

The key is finding a care routine which works for your needs.  Many basic entry level tubs lack the luxury features of higher end tubs which alters what care routines they can use with their hot tubs.

With my  care routine on my Hotspring Highlife 200-gallon spa for example, I test pH once a month (using titration drop test kit), and when it drops below 7.6, I boost with four ounces of sodium bicarbonate (baking soda).  This boosts both the pH and TA.   My pH settles slowly over time so I ride a cycle - boost when low and then ride it down over 6-8+ weeks. 

High pH causes scale which is reversible damage to the spa while low pH for prolonged periods of time can cause irreversible damage to a spa.  So in very general terms its better to ride higher than lower on the desired pH range.

Since it takes a while for chemicals to mix, I usually don't bother testing pH for another week or two (but usually I test once a month unless something seems "off" and then pH is the first thing I test).

With my care routine my dealer provided me with some math for how much granular chlorine to add after each soak - for a 200 gallon spa that is 0.5 teaspoons dichlor per person per 30 minutes of soaking.  This raises the free chlorine levels high enough to sanitize the water after each soak without using too much granular chlorine (which contains roughly 43% CYA stabilizer)

 

On 3/19/2023 at 2:14 PM, md1870 said:

(3) Are there clear guidelines on which water chemicals can be added simultaneously, versus which need to be done at different times? For example, can I add something to adjust water hardness, something to adjust alkalinity, and also add chlorine all at the same time? If not, how much time is needed between adding different types of chemicals? Also, how much time needs to pass before any added chemicals would be expected to show most of their effect, so the water could be re-tested?

Most people suggest you balance TA first, then pH.   I personally only monitor the pH since the baking soda boosts both TA and pH and both tend to go hand in hand (boost one both go up,  lower one, they both lower). Whenever adjusting pH or TA I'd say wait a week for the chemicals to fully 'mix' but that's just me - I don't know if that's accurate or not. 

Personally whenever I fill my hot tub, I test pH to ensure water is within proper range (which it's city tap water - it better be!).  Then I chlorine shock with 3 tablespoons of granular chlorine on a fresh fill to clean the hell out of everything to start.

If during my monthly maintenance I find the pH is too low I boost at the start of my maintenance routine (which includes cleaning filters and conditioning cover), and then I hit with half a teaspoon of chlorine and run jets for 10 minutes before closing cover.

After every soak I dose with the proper amount of chlorine (I use a spring loaded sugar dispenser so it's easy for my wife - one click per one "dose")

On 3/19/2023 at 2:14 PM, md1870 said:

(4) So far I have only left the cover open after adding chlorine (dichlor), leaving it open for 30 minutes. Otherwise I close the cover immediately after adding anything. Does it need to be left open for any other chemicals? Whenever I add anything I run two of my four jets for a 20-minute cycle. 

I would leave the cover open for at least 10-30 minutes after adding any chemical just to play it safe. My Hotspring has a "clean" button which essentially runs the jets for 10 minutes then turns off.  I always hit that button when adding any chemical to the tub.

 

On 3/19/2023 at 2:14 PM, md1870 said:

(5) My hot tub has an ozone system. My understanding is this should be responsible for most of the decontamination, and therefore much less chlorine is needed. However, it also means the chlorine reading is extremely low unless I have added chlorine very recently. How do I know whether I'm adding the right amount of chlorine? 

Ozone burns off organic contaminants through oxidation (like shock) but is such a strong oxidizer that it even reacts with free chlorine. This means you can chlorine shock after use and not have to soak in a bleach bath the next day, because the ozone will burn off all the chloramines and most of the chlorine overnight.

With my care routine as mentioned I am only dosing with chlorine after each soak (or after I touch the water, for example to remove the filters and clean them).   The circulation pump hooked to the ozonator (and a Nature2 Silver Mineral cartridge) keep the water clean between soaks.    If I open the cover and the water looks turbid or has a foul odor, I know to first test the pH and then chlorine shock with a few tablespoons of chlorine with the cover off for 30+ minutes, but it's very rare I need to do that.

The other thing I do before every drain/refill is to purge the plumbing with a product called AhhSome - the cleaner your internal plumbing, the less sanitizer you'll need to keep the water clean/clear.

As cranbiz mentioned, CYA is a factor - granular dichlor56 chlorine consists of roughly 43% CYA stabilizer compound (which is basically a UV 'sunscreen' to protect chlorine in pools from sunlight breaking it down as fast - but totally useless in hot tubs).  CYA will build up in the water and there is no way to sequester - you must drain/refill once it hits around 250-350ppm as it will start to bind to the free chlorine before it has a chance to sanitize the water - this is a dangerous situation because you keep adding more and more chlorine to the water and it's not working to sanitize the water.

Personally once my water turns turbid, pH is within range and chlorine shocking doesn't work I know it's usually time to drain/refill the tub.  That usually happens every 6-10 months for me because I'm using *very* little amounts of dichlor chlorine to keep the water clean.   The more granular chlorine you use to sanitize, the faster your CYA levels will increase.  For some people that can be as little as 3-4 months or even shorter if they're really careless with chlorine usage.

 

You could use liquid pool chlorine (NOT grocery store bleach), but this is dangerous to handle because it is more concentrated chlorine and a splash or drip can damage stuff or cause injuries.   The benefit to pool chlorine is that it does not contain CYA stabilizer compound, but it's more dangerous to handle which is why most people prefer granular chlorine. 

Alternatively the Frog @ease system uses a proprietary blend of granular chlorine which contains no CYA stabilizer compound, but since it's proprietary to the brand it's crazy expensive in the long run (way more expensive than simply refilling twice a year lol).