GaTub

I travel on business a lot and my wife is chemistry challenged, and we also just got back from a week-long vacation with my nephew house-sitting. Also on Nature2. I make sure the tub is full and the water is in really good shape, and hit it good with chlorine just before leaving. Then I leave a bottle of N2 strips and MPS at the tub and hide all the other chems. I get whoever is at the house to check it with a test strip once a day and add 1-1/2 tbs MPS only if the level on the strip reads low. And no hot tub parties! When I get back I check the balance with the K2006 kit and add chlorine. If the tub has been used the water might be a little cloudy but the chlorine clears it right up. This has worked good for me for trips up to 10 days so should work for you. If your water is nice and clean before you leave it will take very little additional MPS to keep it that way if nobody uses the tub while you are gone. And even if your house-sitter uses it some the water should stay OK as long as she watches after MPS. If she invites friends over for a party then that is another story- anything can happen.

Buried away in the last post.. That's the beginning and the end of it. For heavy usage there is not much difference since you still have to add a bunch of chlorine to keep the water clear. But with N2 I feel comfortable leaving the tub for a few days if the water is in good shape and it is not being used. I wouldn't want to do that relying on chlorine only.

Usage makes a big difference, probably regardless of the system used. I've found that with N2 and two people for short soaks several times per week the recipe works fine. But with heavy usage there is a need for more chlorine or things can quickly go bad. Got home last night and found my wife and several of her friends hung out at the tub all yesterday afternoon. She added MPS and the level looked OK on the strip, but I added a bunch of chlorine anyway. Everything looks great this morning. I've learned to stay a step ahead Yes, my pH tends to gradually drop with time but adjusting once every week or two is not much trouble. I use the K2006 kit for pH and other measurements, and N2 strips to monitor MPS. Using the system for 6 months now so starting to feel like a pro of sorts. Well at least not a newbie anymore.

Given that they gave you what sounds like Nature2 test strips and MPS to add you almost certainly have the cartridge- but you absolutely need to confirm this. We are on Nature2 and it has worked fine for us once we got it figured out. But you have to follow the instructions on startup. Are you positive that the technician did not add any dichlor when the tub was first filled? No matter what you do you will need to adjust your chem additions based on bather load. If you have 7 kids in and out of the tub it is going to take a lot of chems to keep the water clear. And with a bather load that heavy MPS alone is definitely not going to be enough- you will need to add chlorine too. It will take some trial and error to figure out how much for your tub usage. Spend some time here reading through posts on Nature 2 and chlorine systems and you will get a better idea of what you need to do. Dark purple on the N2 strip is not a worry- it won't stay that way for long if you use the tub. What is a worry is not putting enough MPS in so that it drops to 0 by next morning. Also the N2 strips are fine for measuring MPS level but agree with everyone else here that you should get a real test kit to measure everything else. Especially since the tub is new I would consider draining and re-filling, this time adding dichlor on the fill-up per the instructions. You can re-use the cartridge that you have (assuming that you have one in there.) Once you get things straight then be sure to read the sticky post at the top of the forum about adding dichlor and buildup of CYA. Even though we are on Nature2 we switch over to bleach for chlorine adds once CYA is built up to over 30 or so.

Since you brought up industrial systems- I may be a newbie at hot tubs but not at water on a large scale. Years back I was the engineer responsible for a water bottling plant that used ozone for sterilization. We injected the ozonated air into the water using a venturi and then ran the water into the bottom of very tall cylindrical tanks to maximize contact time. The tanks had to be vented to let the air out and a special carbon filter system was used to get most of the ozone out of the exhaust air. I spent a lot of time working to maximize O3 concentration and contact time, and also to keep the ozone out of the air in the factory. Things I learned- it actually takes a very high ozone level to completely sterilize, ozone is extremely corrosive, and it is very nasty stuff to breathe even at low concentrations. I do not have ozone in my tub. It may work OK if the system really produces enough ozone to do any good, but then I don't ever want to smell the stuff again and the thought of it accumulating in the air under the cover is a real downer. Our tub came with the Sundance UV system. Its a far cry from the industrial UV systems that I have used and even the industrial systems are only good for reducing micro, not sterilizing. So I don't know how much the little hot tub UV system helps, but at least there are no downsides other than replacing the bulb.

Here goes... Almost all of the experts here are on bromine or daily chlorine so advice here on Nature2 is a bit limited. But we have been on the system since our new Sundance tub was first filled in March. After a bunch of errors the first month or so we seem to have it worked out. We are now into the third month since the last fill and the water has stayed perfectly clear. It sounds like you are doing this on your own so you will need to start at sqare one. The first step is to get the water balanced. Our dealer tech just added a phosphate buffer (Brilliance pH true) during the first fill and that has worked fine for us. But our city water is very soft, almost no hardness, and I don't know if it would be a good system for you- it may depend on the water quality that you are starting with. But you need to get the water balanced somehow. Once your water is balanced follow the instructions in the link that Dr. Spa provided for initial startup. The only difference- I put the N2 cartridge in the well instead of inside the filter. Reading through threads here putting it inside the filter can cause problems and it works just as well on the outside. The new high-end Sundance spas actually come with a pocket in the well door for a cartridge so putting it inside the filter is definitely not necessary. Once the chlorine level from the initial dichlor add drops down you will need to start maintaining MPS level. Make sure that you have Nature2 test strips. Test strips in general don't work that well, but the N2 test strip MPS level readings are actually quite good and its by far the easiest way to measure MPS. Here is the tricky part- you will need to adjust the MPS add amount/frequency based on how much the tub is used. If the water is in good condition and the spa is not used much then we find that the MPS will last for several days or even longer. This is a big benefit over going with chlorine alone. But if the tub gets a lot of use then it takes more MPS because it gets used up oxidizing bather waste. Also the MPS alone may not be enough to keep the water clear when the tub is very heavily used. Then you need to add some chlorine. Even if our tub is not very heavily used I still hit it with chlorine once every week or two just to be sure. The N2 instructions mention this but are not very specific. Also once enough dichlor has been added to build CYA up to 30 then we switch over to Chorox as described in the dichlor/bleach thread posted at the top of the forum. It takes very little dichlor to build up CYA so you need to be watchful of this even when using the N2 system. The Taylor test kit is a good tool to keep an eye on water balance and pH. With the system we are using I have to add a little pH up every couple of weeks and thats about it. Keep the dog out of the tub (don't ask!), make sure everyone is reasonably clean before getting in, and enjoy!

We are newbies at this too, but since nobody has responded yet... We have been spa owners for 2-1/2 months now. The first few weeks was a comedy of errors when it came to maintaining water quality, but I spent a lot of time reading through the water chemistry section of this forum and learned a ton. I drained the tub and started over with my new-found knowledge and haven't had a problem since. The key is understanding what you are doing and working out a system. I don't know about Bromine, my tub doesn't have an ozonator, and I can't speak to the best way to maintain pH. But as a "successful newbie" here are some general things that I have learned- The amount of chemicals required depends a whole lot on usage. With me and my wife using the tub less than an hour a few times a week it takes very little to keep the water crystal clear. But add in some guests, multiple uses in a day, long soaks, etc- and the amount of chemicals needed goes up a whole bunch. We are not real sticklers for showering first, but this also seems to make a big difference. Bottom line it is not as simple as adding a tablespoon of this or that a day. And once the water gets cloudy it can take several days to get it back to right again so its best not to let it get cloudy to start with. All that said once you get a feel for it and have a system worked out its pretty easy. Also the advice that I've gotten here has been much better than the advice from the spa dealer. For example I was surprised to find out that adding dichlor granules quickly builds up cya which reduces effectiveness- found that out here, not at the dealer. I suggest that you spend a few hours reading through the water chemistry section. After a while it starts making sense. Then choose a system (chlorine, bromine, N2) that is best suited to how you will use the tub and learn all you can about it. Keep the faith and good luck!

Almost a month since the water change and everything is good- nice clear water, no deposits, slime, or foam, and TA and pH are stable. A followup question for the chem experts- how much residual MPS is needed in order for the N2 system to be effective at disinfecting? I am adding some whenever the level gets to "low" on the N2 test strip and that seems to be working. But if it gets to 0 will the cartridge continue to work for some time- hours, days? I know that fc should never go to 0 when relying on chlorine alone, but the N2 instructions do not really say anything about maintaining residual MPS. I am hitting it with some chlorox once per week and also added some the few times that the tub has been very heavily used. That also seems to be working good.

As long as it is fully submerged, water is circulating around it, and its not restricting the pump then I am sure you are good to go. And once the chlorine level comes down the water will feel a lot better. It may take a day or two if the tub is really clean and you mistakenly put more in than needed (ask me how I know this!)

The filters on my Sundance have a closed top and screw right onto the pipe, and sliding the cartridge into the filter as suggested doesn't leave it in a very secure position. So the tech that set my spa up just put it in the well outside of the filters. I've read here that others are doing the same thing and it seems to work fine. So I think where you have it should work good. Since you are new to this and using Nature2 be sure to read my post in the chemistry section. I went through quite a comedy of errors when I first got mine set up a little over a month ago. Almost 4 weeks now since I replaced the water and everything has been fine since. A couple of things- the N2 strips are very good to have since it is the easiest way to tell that you have some MPS in there, and at least some residual MPS is necessary to make the system work. Also if you supplement with chlorine be sure to pay attention to the buildup of CYA that happens if you keep on using the granulated crystals (dichlor.) The experts here are right on target with advice about that. Spend some time reading in the chemistry section- its well worth it.

We are back to using the tub, with a couple of people soaking at least an hour or so each day. I am following the N2 system to the letter and the water is sparkly clear, and there is no foaming. According to the strips the fc is fully depleted and we are now relying on the MPS and the cartridge, along with the UV. When I tested fc last night using the K-2006 kit a light pink color developed in about 10 seconds or so. I could knock it out by adding about 14 drops R-0871 but then it came back again after a few seconds. I assume that this is due to the MPS, and since everything looks good I will use this as my baseline. I know my test chemicals and method are fine because I tested my city tap water and the response was normal with a sharp titration endpoint, showing a trace of fc (<1 ppm) which is exactly what I would expect. Testing the water has actually gotten to be fun- reminds me of my college organic chem labs years ago!

The fill capacity of the tub is 390 gallons. Not sure where I got the 470 from (too many numbers running around in my head!) But that accounts for the higher than expected fc when I added the 2 tbs dichlor. It is dropping very slowly, but eventually should get in range, right? I just made up a little notebook with all of the assorted conversions, and suggested add amounts based on my 390 gallons. And I will log in usage, chem adds and test readings for a while until I get a good feel for what I need to do to keep the water healthy. My plan is to follow the N2 instructions, and shock fc to 10 ppm or so once each week for a while regardless of whether it looks "needed". I am hoping/thinking that the fc depletion rate after the shock should give me an indication of the health of the tub. And then I will adjust MPS adds if needed based on how we are actually using it- but never go below the recommended adds in the N2 instructions. The N2 instrutions don't say anything about it, but is there any reason not to use Chlorox for fc shocks instead of dichlor once I get to the 30 CYA level? I don't want to get CYA out of control again! And this should also reduce the tendency for pH to drop. According to the pool calculator it will take about a cup (8 oz) to bring cc from 0 to 10 ppm in my 390 gal spa. Does this sound about right? Getting tired of making mistakes so a double check would be appreciated.

The water is perfectly sparkly clear and absolutely no foaming so far even with all the air jets wide open. But we haven't used it yet since the refill. I'll let you know how it goes as things settle in.

I have the chemistry down now and agree 100% on the the dichlor and CYA. But I wasn't going to convince him no matter what- think I may have hurt his pride by pushing it as far as I did. On the other hand the showroom is literally only 2 miles away, and they are the only spa dealer for at least 100 miles in any direction. I have no problems with the deal on the spa or the work that he did to install it. And all-in-all he really is a nice guy. So no use making an enemy over what amounts to a bit of ignorance especially since I don't need his chemistry "expertise". Like I said I am going to give the N2 system a shot, and if it doesn't work out I'll try the dichlor/bleach method next. If I go this way I will probably have to order boric acid off the net since the supply of spa chemicals is a bit limited at the local dealer. But no problem doing that. My fc hasn't dropped at all today- still stuck at 13 ppm. Now thats a different sort of problem to have, but a welcome one.

The correct answer is/was YES. I went by the dealer with a water sample and he confirmed all my test results. Then we got in a bit of a debate. I told him the high CYA was undoubtedly due to all the dichlor I added. He disagreed, saying that the dichlor that he gave me was not stabilized, it will not increase CYA, and that the buffer was probably affecting the test. Anyway I decided to go ahead and change the water. Nothing fancy- I just drained, cleaned the filters, and refilled using the same phosphate-based buffer and the N2 cartridge. It only took a few hours. I primed with 3 tbs of dichlor and let it sit overnight. I just checked the chemistry- what a difference! fc - 13 ppm cc - .5 ppm pH - 7.6 TA - 160 Hardness <20 CYA <30 When the tub was first filled brand new the fc dropped to almost 0 by the next morning, so this is a big change in itself. This time, after 16 hours it has barely dropped at all. There must have been something in the tub to start with that affected the balance. Everything else is right in range and the CYA is lower than the K-2006 kit can test for. Lessons learned: Don't blindly trust the local dealer for chemistry advice. If the balance goes way out after the first day then plan on draining and refilling to remove any deposits that may be in there from the factory. Don't let the dog go swimming! Be careful with dichlor additions. I now have a bottle of chlorox sitting alongside my other chemicals. I am going to try using my version of the N2 system because I think it will be easier for my wife to manage while I am out of town (I travel very frequently). But now I know what to watch for, and if it doesn't work out I will try the posted dichlor/bleach method next.