simonc

I'm sorry that I don't have an answer to what is causing your yellow spa water. However, I do have some suggestions that might help you identify the cause and solve the problem. So, here goes ... 1. A spa is NOT a small swimming pool. Because of the high water temperatures, it requires more monitoring/testing. 2. Have you tried shocking with Chlorine? Many people use non-chlorine shock, but this does a poor job of killing algae and growing things in a spa. Go the the poolcalculator, look at the bottom of the page and figure out how much chlorine you need to add to your spa to shock it. If the chlorine shock clears up the color, then you know it was because something was growing in the water. This is not healthy for you or the spa. 3. You said you had the spa recently installed. If it made with concrete, plaster, or tile you might get some leaching of the new material into the water at higher temperatures (and different pH, etc.). This could cause your water to change color. I would check with the installer/manufacturer to make sure that it's not the spa construction material. 4. Once you solve your yellow water problem, I would get a good test kit so you don't have to take your water somewhere to get it tested. Spa water should probably be tested at least twice a week and more frequently if you have a high bather load or water balance problems. Test strips are only good for a quick assessment. They will not help you solve or prevent water problems. Good luck and let us know what you did, - Simon

First, welcome to the forum. I'm not sure I understand your question. Do you mean when your chlorine drops to zero (not a good thing) your pH drops also? In order to help you, it would be useful if you ... 1. Clarify your problem/question. 2. How are you measuring your spa chemistry? Test strips? If test kit, what type? 3. What kind of chlorine are you using? Some types of chlorine (triclor) are very acidic. 4. What are your numbers? How much does your pH vary? - Simon

To answer your questions ... 1. The temp depends on the directions for the flush product you use. Follow the directions on the product. I've tried "Spa System Flush" and "Spa Purge". Spa System Flush worked much better in my case. I would recommend it over the other. Generally, these are enzyme/detergent products and work best at higher temperatures ... just like your clothes wash cleaner in warmer water. 2. I don't think you need to raise the temperature for the chlorine shock portion of the procedure ... at least I didn't. If my memory serves me correctly, you only run the spa for about an hour or so with the high the chlorine which is too short to raise the spa temperature. Also, 50ppm of chlorine with no CYA as a buffer is a very high concentration. Raising the temperature on this very strong chlorine concentration might do some harm to your spa components ... the soft rubber parts, like pillows, would be very vulnerable to damage. Good luck, - Simon

I did Nitro's decontamination procedure twice on my tub. The first time I used "Spa Purge" but it didn't work very well. The second time I used "Spa System Flush" and it worked much much better. Here's my experience. I've had my tub for about 4.5 years. During most of that time I used diclor/triclor for sanitation. I was having problems maintaining the water balance/sanitation. In Fall 2009, I joined this forum, learned a lot, and switched to the diclor-then-bleach method. It worked much much better than diclor/triclor alone. However, even with diclor-then-bleach, I was having a problem with a high chlorine demand and having my CC's regularly in the 1-2ppm range. I did a number of super chlorine shocks, but the effect was only temporary. I decided to do a decontamination. I had never done one before on my tub. I went to the Leslie Pool's dealer and and bought "Spa Purge" for $20. It's the only brand that dealer carried. When I opened it up, the stuff inside the bottle was a yucky brown color. This struck me as strange because most spa chemical manufactures try to make their products look clean and attractive. I called the dealer and he reassured me that the stuff is suppose to be yucky brown. So I went ahead and used it. I followed Nitro's recommendations, and let it sit overnight. The next morning, I went to drain the water. I expected that I'd find some type of gunk around the water line, but there really wasn't any. I figured I had a cleaner tub than I thought. I followed the rest of the procedure. When I refilled my tub with clean water, my high CD and my high CCs returned quickly. Again, I tried super shocking, but it's effect was only temporary. After about 6 weeks of dealing with the CD and CC problems, I decided that I needed to do another decontamination. This time I ordered "Spa System Flush" on the internet, about $17 dollars with shipping. I did the procedure again. With Spa System Flush, I got a lot of gunk at the water line, unlike my experience with the Spa Purge product. Use of the Flush product formed a sticky greasy bathtub ring that took some scrubbing to get off. The ring was a yellowish/brownish color. Maybe from using the brown colored Spa Purge previously??? So far, my CD is much better (I don't have a number yet, just an impression.) and my CCs are near zero. It's still too early to tell if this improvement will last. In all fairness, I can't say that I can fairly compared these two products without any variation in procedure. However, the main reason I think the Spa System Flush beat Spa Purge is that I didn't get any bathtub ring with the Purge product but I did get one with the Flush product. Here were some of the differences in my very unscientific experience: 1. The Purge product requires an entire bottle for one cleaning. So I used most of the bottle. I have a small spa - 3 person, 275 gallons. So one bottle should have been sufficient. 2. The Flush product only requires 1/2 bottle for a 400 gallon tub. I used the whole bottle in my 275 gallon tub anyway. If a little is good, a lot is better??? 3. The Purge product instructions say to set the water temperature at least at 98 degrees. I set it at 100. 4. The Flush product doesn't indicate a specific temperature, but I set my temp at 104 degrees, againg figuring more is better. Anyway, that's my experience with these two products. - Simon

Mike - I agree with the others on this ... if you are properly sanitizing your tub, you shouldn't have to use clarifier. Before I joined this forum, my solution to almost every tub problem was to add another chemical. I learned that a lot of my problems (cloudy water, foam, bad smell) were due to the fact that I was not killing all the things growing in my water (algae, germs, other microbes). I was always adding some chemical/treatment which my dealer was more than happy to sell me. It solved the problem (actually, the symptom of the real problem - poor sanitation) temporarily. Then back to the dealer (or hardware store) for more chemicals. The best writeup on how to maintain your tub properly is this one: click here. It's a little intimidating to read. Read the whole explanation by Nitro and then go his summary section. This highlights the keypoints. Once you get your water balanced after refilling your tub, it's really just a matter of adding plain clorox bleach on a frequent basis. This is easy if you use your tub a lot like I do. (However, if you only use it only occasionally, the diclor-then-bleach method is probably not the best method.) Also, you should get a good test kit like the Taylor K-2006 so you can actually measure the important factors in your water. Test strips are OK for a quick check of chlorine or pH before you jump into the tub, but they don't work well for properly balancing your water to avoid problems. Good luck, - Simon

Chem Geek - If you say not to worry about it, I won't. I'll re-measure tomorrow and make sure I got my numbers correct. Lastly, I got my directions wrong on the TA. If I want to move my CSI closer to zero, I need to increase my TA, not lower it. I think? I can do this by adding a little baking soda. Tonight I'll soak. Tomorrow, I'll measure and balance, leaving the CH at 240. - Simon

I was balancing my water and needed to raise my CH from 80 to 180 to achieve a near zero on the CSI. (My TA is 70. pH usually in the 7.4 - 7.6 range.) I used the pool calculator and found that I needed 5 oz. (by weight) of calcium. I got out my scale, weighed out 5 oz. and then, in two installments, added it to my tub. (Yes, I probably should have measured my CH after the first dose, but I didn't. How could the pool calculator be wrong?) Anyway, my CH is now 240. How can I lower it? The pool calculator recommends removing water and then replacing it with zero CH water. I don't have zero CH water so my guess is that I would have to remove 1/2 of my water to achieve a CH of about 180. Also, I would then have to rebalance everything again. No fun and a lot of use of expensive Taylor reagents. So ... Can I add some "Stain and Scale Inhibitor" to lower the CH? The container says it contains 10% polyphosphonic acid ... whatever that is. If so, how much should I add to bring CH down to the 180 level? (I have a 275 gallon tub.) I know I can lower my TA to "balance" the high CH. I usually keep my TA at about 70 or 80. If I lower it too much I'm afraid I'll have problems with pH fluctuation. Any other suggestions? Thanks, - Simon

I think the "theory" behind filters increasing the CD is that the filters capture organic material - dead skin cells, hair, bugs, etc.. These organic materials decompose in the warm tub water and this uses up more and more chlorine over time. It's a theory. I don't think anyone has tested it to see if it is true, but it does make sense. - Simon

I also had a "strange" experience measuring CC's with my Taylor K-2006 kit. I measured it as 1ppm (2 drops x 0.5ppms). I put the cylinder down for a few moments still containing the test water. I noticed that some of the pink color had come back. I added another drop. It disappeared. Just for fun ... I let it sit longer and again it turned pink. I did this over and over again. Each time it took longer to turn pink, but it did turn. At my 8th drop (about a 10 minute wait after the 7th drop), I got bored of the "game" and tossed the water out. I don't believe that I had CCs at 4ppms (8 drops x 0.5ppm). If I did, it wouldn't have turned clear after just two drops. I put in some MPS and decided not to worry about it. - Simon

QCD - Thanks. Until you pointed out the "Effects of adding Chemicals" section in the poolcalculator, I never even noticed it existed! It's at the bottom of the page ... I never looked down that far. I sincerely appreciate your efforts to not only provide information but also to "educate" the rest of us. Actually, I find the chemistry interesting, although somewhat incomprehensible. Without technical people like yourself, this forum would be much less useful. Thanks, - Simon

QCD & Chem Geek - You can say that again. Specific gravity? Moles? Sodium this and sodium that? So ... back to my original question ... Approximately how many ppms of salt does a 500 gallon tub have after using up a gallon of 6% bleach? The BEST answer would be a SINGLE number WITHOUT a "it depends" in the answer. Positive integers (not too big!) are things I can comprehend. Thanks to both of you for doing the analysis and calculations, but all I really wanted was a number. - Simon

QCD - I don't want to get a meter or salt test kit, but can I estimate how much salt based on how much chlorine I've added? Since I use a gallon jug of 6% bleach as my chlorine source, I know how many jugs I've gone through in a fill. My salt level should mostly result from how much bleach I've added since the fill was new. Therefore ... I should be able to roughly estimate my salt ppms based on the quantity of bleach I've used. Correct? So ... approximately how many ppms of salt does a 500 gallon tub have after using up a gallon of 6% bleach. (I assume this is an easy calculation for someone like yourself who knows what they are doing with chemical calculations. If it's a difficult calculation, please don't worry about it. I can live without knowing my salt ppm level.) (Just a note on "jug size" ... pardon the expression ... The Clorox I buy at the supermarket is comes in 3 quart jugs. The ones I buy at Costco come in the larger one gallon size.) Thanks, - Simon

Chem Geek & QCD - Thanks for explaining TDS. I don't think I'm going to worry about it for my hot tub. The solution to high TDS in tubs seems to be ... when in doubt about TDS, just drain the tub. In swimming pools, I can see measuring TDS is more important because draining can be a lot of work and expensive. I'm not going to get another test kit/device. My wife thinks I play with the chemicals in the test kit too much already. It's sort of fun, actually. I'm old enough to remember "Chemistry Sets" that actually contained things that by today's standards would be too dangerous and way too much fun. No ... I don't want my tub to blow up, but ... it would be cool. - Simon

Chem Geek (Richard) - Thanks for discussing this topic. I have a few questions: 1. How do you measure TDS? I don't think it's part of my Taylor K-2006 test kit. 2. Is it important to test for TDS? TDS seems not to be discussed very much in this forum. 3. Is salt the major component of hot tub TDS for chlorine based systems? If so, a high TDS would imply a lot of salt. So why not just test for salt directly instead of TDS? (I don't know how to test for salt either.) Just trying to learn ... - Simon

Anyone else with experience using the Nexa brand SWG? Any experience with other specific brand aftermarket products? The general consensus from other post on this thread seems to be negative about SWGs in general. Of course, if I owned a YUGO, I don't think it would be fair to generalize to all cars made in Europe. Different brands are different. Are they all more trouble than they are worth? There seems to be very little information on this forum with aftermarket SWGs for spas, like the Nexa brand. It sells for about $300. Competitors seem to sell for about the same price. Here's a link to the Nexa. I'm interested in getting one. If it cost only $100 I would take the risk and give it a try. However, at $300, I would like some information before I decide. Thanks, - Simon

seabright_sc - I would disagree with oldparr's suggestion that you dump 1/2 the water. I would dump the whole thing. The reason I say this is that you talk about the water having a "yellowish tint". I have no idea what might cause that, but it's probably not good. I would get rid of all the water and start over. If this is an old or used tub, you might consider doing a decontamination. Because you Chlorine Demand (CD) was so low ... only dropping 0.5ppm a day, it's unlikely that you have something "growing" in your tub that requires decontamination. This is a link to how to decontaminate, if you feel it's necessary. I agree with oldparr that you should consider switching to the diclor-then-bleach method. Your water will last longer, be safer, feel better, and it's probably cheaper than what you've been doing. Your CYA level is probably so high because you've been using diclor (chlorine granules) or triclor (the pucks that are typically used with a floater). These chemicals contain a lot of CYA which, at high levels like yours, interferes with the sanitation process. Lastly, I think you are just guessing at your CYA level (120-150). It could easily be over 200. Let me explain ... I think I have the same Taylor kit and it only measures CYA up to 100. If you look at the marks on the cylinder, you'll see that they get closer and closer together at they approach the bottom. It's a logarithmic scale. It's not linear and therefore it's almost impossible to "eye ball". You can get a more accurate measurement by diluting the test water and then multiplying. Anyway ... this is another reason to dump ALL the water in your tub. If your CYA is really 200, getting rid of only half of it will bring it down to 100 which is still too high. Good luck, - Simon

Jbuck - A few thoughts/suggestions ... 1. I don't think your post is too long. You should see some really long ones on this forum! 2. Cloudy water is often an indication that you are having sanitation problems, i.e., there are things growing in your water because of sanitation problems. 3. If this is a used tub, you should decontaminate it before you refill again. Here's a link. 4. Once you get your tub decontaminated, you should make sanitation your #1 priority. You can get sick from bacteria, virus, and fungus growing in your tub if it's not sanitatized correctly. Here's a link to the best writeup on the subject of water maintenance. The article is long and a little intimidating, but look at the summary section. If you decide to use the suggested diclor-then-bleach sanitation method, it's really very easy and not any harder than other method, some of which are less effective. Good luck, - Simon

As others have noted, adding hydrogen peroxide (the kind you get at the supermarket or drug store) is the fastest way to drop the FC. I don't know the formula, but I think about 2 oz of the stuff brings my FC down about 5ppm. I'd try adding 2 oz, run the circulation pump/jets, wait an hour, and remeasure. I have a couple of questions ... 1. Are you sure you are using the taylor kit correctly? It seems that your chlorine demand is only about 5%. That seems very very low to me. I don't have any experience with maintaining other people's tubs, but my impression from reading posts on this forum, anything under 20% is pretty good. Do you have something else besides FC killing things in your tub? Maybe a Nature2 (silver nitrate) cartridge??? 2. What's your CYA level. If your CYA level is high (100+) having 12ppm is not so bad. If you've been adding diclor or triclor regularly, you can easily get to a CYA of 100ppm If it's very low (close to zero) then it can be destructive of tub components like covers and pillows. I can't speak to how it might effect people's skin if CYA=0 and the FC is 12ppm. Good luck, - Simon

Chem Geek - Thank you for your helpful response. I guess I don't really have a "concern" ... my water smells/feels fine. I was more interested in finding out if one method of "shocking" to get rid of CCs was more effective than another. I appreciate you pointing out that reactions with chlorine happen much faster in a hot tub than they do in a swimming pool, making chlorine a faster oxidizer in tubs. For now, I'll probably rely on a combination of chlorine shock and MPS shock to handle CCs. When my supply of MPS runs out, I probably won't rebuy it and just stick with chlorine. - Simon

QCD - Thanks for helping me with this issue. I would say my tub is not "heavy use". 275 gallons - my wife and I use it in the evenings (15-20 minutes) about 3 or 4 times a week. I have a small container of MPS. I guess I'll continue using it. When it runs out, I probably won't rebuy it. My water smells/feels fine. My CC level is usually around 1ppm. After shocking with chlorine, I get it down to about 0.5ppm. It doesn't seem to go below that. I'm fine with less than perfection. - Simon

QCD - Thanks for the bottom line answer and your detailed explanation. Although I don't have a background in chemistry, you explained it very well and I appreciate you taking the time to show how you got to the bottom line. I was especially interested in the information you gave us provided by Mr. Wojtowicz (see quote above). Again, I don't really understand chemistry (and the various names of the chemical compounds produced) but it seems to imply that Chlorine is NOT the BEST oxidizer for urea. Am I correct in my reading of the statement? If so, what is the best oxidizer of urea? Is it MPS? The MPS oxidation process doesn't produce CCs. It seems that using chlorine to get rid of urea does produce CCs? (I'm assuming that "ammonia chloramines" is a CC???) Please pardon my ignorance. (When I bought my tub I didn't know that I need to know anything except how to sign my name on the check I wrote the dealer.) Is an ozonator the BEST oxidizer of urea? My ozonator is probably not working (4+ years old). Maybe I should get it replaced? I've been using the diclor-then-bleach method in my tub. It seems to be working very well for me. - Simon

I can't compare the two tubs, but I can tell you I like my Jacuzzi brand tub. It's the small model - 3 person - 275 gallons. I don't remember the model number. I've had my tub for over four years and I've never had a problem.We use it about three or four times per week. Everything still works and looks great. There's a lot to be said for "trouble free" ... at least that's my personal experience with Jacuzzi. (Gee ... I hope something doesn't break tomorrow, now that I've said I haven't had any problems.) My only complaint is that the replacement pillows are very expensive. In my model, they are made of two components and together cost about $50USD new (at the dealer), that's about $150 to replace all three. I just took mine off. I don't find the pillows really necessary, but that's just me. Good luck with your new tub, whatever your choice. - Simon

QCD - How much DRY GRANULAR MPS should one use per person-hour? When I add MPS, I have no idea how much to add. Also, how much MPS does one need to add to get rid of CCs? To get rid of 1ppm CC per 100 gallons, how much MPS do I need to add? Is there some type of online calculator to figure this stuff out? Something like the poolcalculator? Or ... does one need to be a chemist? I'm not. Thanks for the great help you've given me and others on this forum. - Simon

Danashell - I can't answer your specific questions because I have no experience with the products you describe. However, I can make some general suggestions that may be of some help. 1. You may have a serious problem with either your water or your sanitation system. Even if you didn't clean your filters, getting only 5 or 6 months life out of them seems extremely short. If your filters were that dirty, something is making them dirty. One possibility (I think the most likely) is that your sanitation system is not working effectively. Things (algae, bacteria) are growing in your water and the filter is getting clogged with them. What are you using to sanitize (kill bad stuff) in your water? The Vision cartridges may not be working or you may not be using them properly. I took a quick look at the Vision website (click here). It says "Vision is a bactericide that compliments Chlorine". Are you sure you're using Vision with Chlorine properly? If not, things will grow in your water and the filter will clog with them. Worse yet, some of these things are DANGEROUS, like bacteria, fungus, and virus and can make you very sick. Hot tub sanitation and safety should be your #1 priority. 2. I've never heard of cleaning your filters once a month. I only clean my when I drain/refill my tub which is about every 3 or 4 months. Maybe some other forum members might comment on how frequently you should clean the filters? If sanitation is the root cause of your "dirty" filters, you can clean them once a day and your problem will not go away. 3. Lastly, you might consider posting your question on another section of this forum. This section here is the water chemistry section (which is an excellent source of information about proper tub sanitation, if that is your problem). The "Portable Hot Tub and Spa" section (click here) has more members that are familiar with tub parts (like filter types) and operation. They might be able to answer your question about different filter styles for your particular brand tub. Good luck, - Simon

Fry Man - Thanks for the info. Your SWG is built into your spa. Probably, if I had it to do all over again, I would consider getting one. But ... I'm not going to do it all over again, so I'm looking for an aftermarket SWG. They cost about $300 and you just drop them into your tub and they generate chlorine (from the salt water). The problem I've run into is that there seems to be very few people on this fourm with any actual long term experience with these aftermarket SWGs. I've found a few threads. I've tried a couple of posts asking for information, but I got very little response. On the positive side, I have NOT found any threads that say "I hate this aftermarket gizmo and I'm going back to fresh water and adding chlorine manually!" Good luck with solving your water problems ... - Simon