bassie123456

I don't think the cal hypo tab would dissolve really quickly, because I put it in a slow dispenser floater. I checked the poolcalculator and in my tub size 1 tab of 7 gram will do this: - raise FC by 3.6, CH by 2.6 , Salt by 3.7. Does not seem like a shocking amount of chlorine, especially since it dissolves slowly I guess the change of it being harsh on the skin is minimal. But I will make sure to check out the instructions for the briquettes to double check. I read some warnings in several post about never letting the FC drop to zero. Everyone getting in our tub is asked to shower before, we don't eat in the tub and the tub is not too hot. So I think that lowers the chances of dropping to zero unexpectedly fast, and if it does I will make sure to get the FC level up as soon as possible once we're out the tub. Like you I don't expect dropping to zero for a short time is too big of a problem if everyong is clean and not contributing diseases to the water I read chem geeks post from your link. Do I understand correctly that at 40 degrees celcius, 5 fluid ounces of 6% bleach would kill one hour bather waste? It would make sense, because no matter the size of the tub I produce an X amount of bather waste at a certain temp. In my case at 37 degrees celcius this will of course be less, but I'll find out by testing it a few times. Draining my tub today btw One quick thing on which I am wondering how others / you do this: what if you go away for like 5 days and your 24-hour chlorine demand (baseline) is close to 35% for example. This would mean that in like 3 days my FC would run to zero (right?). In such situation I would make sure the level FC is a bit higher then usual before my leave. Would it also help to put the water temperature a little down? Or does that only help when you're in the tub (for sweating etcetera)? Also, thanks so much for the time you took to help me out and share your knowledge. I wanted to let you know I really appreciate it and I gained so much knowledge the last couple weeks!

Thanks for helping me understand this! I didn't know temperature has that kind of impact on the generated bather waste. Your example calculation makes sense. I think the first time that I expect to be in the spa for like 2 hours with 4 people I will just make sure to start a little high on the FC. And then after soaking I will test the FC after 1 - 2 hours as you suggested, to see how much is used up, just to make sure it doesn't get to zero all night. Since 37 degrees celcius is not too high of a temperature (I don't have the feeling that I am sweating much at this temperature), I don't expect to burn through the FC very rapidly. I think once I have had a couple of tub sessions and done measurement before and after, I will very quickly get a feeling on how fast the FC is being used up on a typical session. I think I will start to bring my CYA to 40ppm to start with and see how it goes. As for the MPS non-chlorine shock during heavy bather sessions, I have searched for this product over here but I cannot find it. However, if I really expect heavy bather sessions and I am afraid my FC will fall to zero for some time, then I'll probably put a HTH briquette (7 gram per puck) in a floater during the bather session. This mostly adds calcium hypochlorite. Or do you think it would be a bad (health-wise) idea to have this floating around while we are in the tub? Because I have read that chlorine without CYA is too strong for application, so wouldn't these HTH briquettes be to strong? I understand that there is CYA in the water so it won't be an issue once it has been mixed in the water, but since we are dissolving nearly 7gram of calcium hypochlorite directly to the water we are currently in, I don't know if it could be dangerous / too strong for a moment. It's very reassuring that you and your wife are liking the chlorine treatment. I can't wait to finally start using the dichlor-bleach method myself. I will drain and fill the tub this week. I'll let you know how it turned out for us.

HI MPurcell, I am about to change my water and I am working out a couple things on paper as preparation. Reading the dichlor/bleach method again I was wondering one thing about the amount of dichlor I would have to add after soaks. It says: "Approx 7ppm FC per person per hour". But using the poolcalculator I did some math. If I soak for 2 hours with 4 persons in a 330 gallon tub, at 37 degrees celcius (98.6 degrees fahrenheit), this would mean I have to add 4*2*7ppm FC. This means I would have to add something like 125gram of dichlor granule. That doesn't seem right. Did I misunderstand something? Because creating that high FC level in the spa, isn't that damaging the equipment? I understand that this level will be lower very soon due to the chlorine being used, however it seems like an insane amount of chlorine to add.

Cool, keep me posted! I recognize the fear of using chlorine, it's the main reason we used a non-chlorine sanitizer in the first place. I have never used of read much about bromine, but read positive things about that too. I am curious how switching to chlorine turns out for you / your wife. After doing all these research (and after all your help) I am convinced that the dichlor/bleach approach is the way to go (for me at least) and will hopefully give me a clear tub for a longer time.

Got it, thanks! Looking forward to start using the dichlor/bleach method soon!

Thanks for the test-kit directions. I am going to print that out, very helpfull I will do a test with filtered water on my next refill to make sure I know the TA, pH and CH of the source water. But a TA of 30ppm and pH 7.8 is nothing to worry about? Or is this related to CH and should I know my CH value first? All of this doesn't really matter that much for now since I am going to drain the tub next week, so it would be a waste to put much effort in getting the perfect balance on my current fill, however I thought it wouldn't hurt to get used to the Taylor tests in advance of my next refill.

Hi MPurcell, I have finally received the Taylor test-kit. First of all, at the moment my water is treated with a non-chlorine solution (SWT Guardson). It does seem to do the job OK, but I am going to switch to the dichlor/bleach method on my next drain & fill (which will be next week). Mostly because I want to be able to measure what chemicals are inside my water, and with SWT I don't know what stuff I am adding. However, I did some tests with the Taylor kit, the results were: Chlorine = 0 (makes sense since I use a non-chlorine solution :)) PH = 7.8 TA = 30ppm I also tested the calcium hardness, but the description says 'The water should turn red of CH is present'. However, my water turned light purple (for sure not red), is that normal? Does this mean there is no CH present, or should I continue the drop test on the purple solution? I added like 10 drops and the color did not change so the CH must be at least 100ppm I think. It couldn't be very much higher, since I filled the tub with a pre-fill calcium filter. But since I did not know if my base solution for the test was correct, I aborted the test. So, what I find strange is, how can my TA be so low (30ppm) and the PH still be that high (7.8). The PH is very stable at the moment btw, it does not increase anymore from aeration. But still, since the dichlor/bleach method suggests an TA of 80ppm, I don't get why my PH isn't way lower with an TA of 30ppm. I have an ozonator, could this be causing the higher PH with lower TA? Should I increase the TA in this case with baking soda or should I leave it be this low? I don't want to lower the PH using an acid anymore, since very little muriatic acid causes large PH decrease according to a test (probably due to the low TA). Last thing, the water is a little bit cloudy at the moment. Maybe it's more like a mist or something. You see it especially with the leds within the tub turned on. I cleaned the filter very regularely and switched to a new filter recently. The PH should be in an OK range and I use the advised dosis of SWT sanitizer. Since I am going to refill the tub next week, I doesn't really matter that much, but just in case this happens again I am wondering what could probably be causing the cloudiness. PS: The water in the tub is 2 months old, the tub is used like 3 times a week for maybe 1 - 1,5 hour at 97,7 degrees fahrenheit (36,5 degrees celcius). The tub is 330gallons large and the filter is on for like 5-6 hours a day. I already added a clarifier (leisure-time) which is meant to clear cloudy water but it did not change anything. Thanks again!

Alright, got it! Thanks a lot for double checking.

What is a common dichlor product sold in the US? I checked the chemical formula for this product: https://www.walmart.com/ip/Swimmer-s-Choice-Swimming-Pool-Dichlor-Granular-Shock/45379075, and it also contains sodium in it's formula? Same goes for: https://www.walmart.com/ip/Star-Plus-Completely-Soluble-Dichlor-Granular-for-Pools-Spas-50-Pound-Bucket/257713676 Here's the MSDS for both products: - http://www.kellysolutions.com/erenewals/documentsubmit/KellyData\OK\pesticide\MSDS\86353\7364-45-86353\7364-45-86353_Swimmers_Choice_Granular_Shock_12_13_2012_5_18_03_PM.pdf - http://www.kellysolutions.com/erenewals/documentsubmit/KellyData\OK/Pesticide/Product Label/75217/69470-20-75217/STAR_PLUS_DICHLOR_GRANULAR_2_1_2017_2_38_33_PM.pdf

Ok, thanks. It's weird, I contacted a few stores but they all do sell only sodium/natriumdichlorisocyanurate.. Dichlor or Trichlor is only available in pucks but not as granular to shock the water. Maybe I will try to crush the chloor pucks to have it dissolve faster

Hi, I ordered trichlor on a webshop (it was sold as trichlor - trichloroisocyanuric-acid (100%)) However, now it is delivered I read the package and it says: natriumdichlorisocyanurate (100%). Is this good too? I compared the chemical formula with trichloroisocyanuric-acid and the difference is the NA (natrium). Is it harmless that this contains natrium or should I sent it back and get the trichloroisocyanuric granulate instead? Thanks!

Got it! Thanks!

I just did 2 iterations to lower my TA using muratic acid and aeration. First time the PH came up really high (8,0 after 30 minutes of aeration), second time it raised only to 7,7. However, I am wondering if it does any harm to equipment to iterate through this proces really fast. Or is it reommended to wait a day between doing a second round of adding acid and aearating the spa? I have added quite some acid to the pool to lower my TA, the acid concentration is only 10% so it is not very high concentrated, but I am afraid that I do damage to my spa if I add lots of acid in short periods of time? (PS: I added like 140ml of 10% acid to my 1250 liters (330 gallon) spa)

Alright, thanks a lot! I read the article and get that on my spa it won't hurt to have a negative value using the dichlor/bleach method. Also thanks for the advice on mixing bleach with acid, I'll take care and make sure to not mix them directly or close to each other. I'll replace my water as soon as the Taylor test kit is delivered and from then I'll start using the dichlor/bleach method with the products I can get over here. Many thanks to the time you put into explaining all this to me, I really appreciate it!!

Cool, So I will order the boric acid to add borates on my next water refill. I will make sure to dissolve the powder in hot water before adding it to the spa. The muriatic acid here is available in 2 concentrations. Either < 10% or 30%. Af for the bleach I have only found 1 bottle without added scents and it says < 5% but I will look into a couple different stores sone to see if I can get something else. As for the math, I think I will work it out using the pool calculator. Btw, on the bleach bottle I bought it says 'Toxic gas will be formed when in contact with acids such as muriatic acid'. Since my pool maintenance is mostly going to consist of adding acids and bleach this text frightens me a bit.. Or does this warning only apply when the bleach is mixed directly with an acid? Edit: one more quick question. The pool calculator says my CSI is -0.35, should I worry about that? This is when I set the following goals: FC 10, PH 7,5, TA 80, CH 150, CYA 50, SALT 1000 (default value), Borate 50. These numbers are based on the dichlor/bleach method but I read that CSI must be as close to zero as possible? I noticed that the TA has most impact on the CSI, but it seems like to get a good CSI my TA should be way higher?

I read that using Borax/MA is quite a struggle (https://www.troublefreepool.com/threads/123049-Boric-acid-Powder-or-Granules) so I would definitely prefer boric acid since that is less trouble. The product you referred to (https://www.da.nl/product/41697/boorzuur) is boorzuur which translates to boric acid (zuur=acid). So that would mean this is boric acid right and I don't need to do anything with MA? If I look for the chemical formula it says 'boorzuur' is H3BO3. Doesn't say much to me, but maybe it does to you. It is a powder though, I cannot find it in granular form. Appeartanly I have 2 options: https://baking-soda.nl/product/borax/ > This obviously needs an Acid according to your research and checking the Pool calculator. The website even states (in dutch) 'Note that this is not boric acid'. https://www.da.nl/product/41697/boorzuur > This must be boric acid (but in powder form). Because it literally translates to boric-acid (boor-zuur) So I guess the second product will work for me! One more question. I went to some local stores, and I found muriatic acid, however the concentration is < 10% of hydrochloric acid according to the label. I found the same product online as a 30% concentration solution. I think the concentration does not matter as long as the math is good about how much hydrochloric acid I am adding, right? And should I check what the rest of the ingredients of the muratic acid is, or is that always OK? Because the label does not say anything about it, it only says a percentage of hydrochloric acid. As for the bleach, I found a bottle with no scents added (quite hard to find) and with no thickeners or anti-splash solutions added to it. It contains < 5% natrium hypochlorite. The dichlor/bleach method refers to a 6% clorox bottle, I assume that like for the muratic acid it is fine to have less percentage of natrium hypochlorite in it, as long as the math adds up?

Sorry for the many posts, however I did find some product on a dutch webshop. The product is named 'Borax'. Consists of a salt named: dinatriumtetraboraat-decahudraat which seems like dutch for: dinatrium tetraborate decahydrate. Is that the right stuff?

By the way, it seems like the only thing not available around here is Borates. So hopefully it will do fine without. If you have tips on what to look for in a pool store for borates, let me know, maybe we do have it but under a differrent naming..

Alright thanks for clearing up about the CYA levels. Thanks so much man. I really appreciate all the information and help. I learned so much, and I think I have no questions left PS, my temp is almost never higher then 38 degrees celcius (I sweat way to much then), so I think the hourly chlorine demand would be lower then 6/7 on average.

Ok great, makes sense! I get the total process now. It's insane how less I did know after owning a tub for 1,5 year. I was really bad informed when buying the spa, because they haven't said a word about TA, Calcium or even CYA. All these things matter and I get how things affect each other. I am however afraid of one thing: We get friends over quite regularly. So we can sit for like 2 - 3 hours with 4 persons in the spa. This would take op a lot of free chlorine How can I keep up with the level of free chlorine during and after these kind of soaks, without having to add a huge amount of bleach before the soaks? (because that would smell I assume plus I don't know if it's good for our skin to bathe in such a high level of chlorine) I am now thinking, what if (during times of heavy soaks like a 3 hour soak with 4 persons) I put a trichlor puck in a dispenser? This would keep my Active Chlorine level OK during soaks (I assume). And yes, it will build up the CYA but if that means I have to change my water a bit earlier then I'm totally fine with it. I read that problems with CYA will start mostly at 100ppm, so from the starting situation of 30ppm, it wouldn't hurt to add some extra CYA during havy bathing loads right? As long as I keep track of the CYA and it doesn't get above 100(?)ppm then it wouldn't cause too much trouble I assume?

Hi @MPurcell, my spa has an ozon filter / purification system or something like that. Does this impact my treatment / any pitfalls to the treatment when my spa has this?

Alright, this is starting to make sense! I can get trichlor granular (I now only have tabs, but they do sell the exact same product as granular), so I will buy that since it will dissolve way easier. I think I can get all the products and have all the information to get this new way of treatment started. I am going to do some shopping and see if I can get all the stuff needed. So many thanks for your extensive information and help.

Thanks again guys! @arobbert, it's indoors and it is covered. It's a 5-person spa with 1250 liters volume. That a chlorine solutions does not contain CYA won't be a real problem for me because I can buy this seperately (stabilizer) @MPurcell Really helpfull again! So, Calcium Hypo is not recommended. I checked some stuff I bought in the past and found a box of trichlor tablets as it seems. The chemical in it is: trichloroisocyanuric-acid (100%). So this ads chlorine, as well as CYA right? So I could use this at the startup and once the chlorine level is OK switch to bleach (and so on). I get your point about the incorrect usage of dichlor of trichlor. However, what if you want to increase your chlorine level, but not your CYA level? Is that what the bleach does? I understand if someone thinks the pool needs more chlorine and they add dichlor, then their CYA level gets too high, and so on. So how can you seperately manage your chlorine vs CYA levels when using dichlor/trichlor solutions? Thanks again! Ps. Sorry for all the questions. It's hard to find good info on this in The Netherlands, and many products refered to on this forum are not available in The Netherlands (at least not under the names they are listed here), so it's a bit hard for a newby like me to figure it all out. But I'm slowly putting pieces together thanks to you guys!

You are totally right It's the same thing indeed. Thanks! So, I think I can get all the things to get started on the dichlor method (assuming the HTH briquettes are OK to use).

Btw, I did some research on Glorix and it seems to be Natrium Hypochlorite instead of Sodium Hypochlorite. Basically any bleach product I have checked out uses Natrium Hypochlorite.. I have checked like 10 products and it is all Natrium