Scotte Posted August 25, 2009 Report Posted August 25, 2009 I have a 2008 Tundra Onzen tub and have now had the Onzen electrodes replaced 3 times since the end of July 2008 - every 3 months roughly. The electrodes have a lot of solid white stuff that collect at the back and part of the front to the point that the mist isn't showing anymore. The CP setting is 6. The service tech thinks that the white stuff is calcium but hasn't got it confirmed. He replaces a lot of these electrodes, all with the same problem After the second replacement, I emptied the tub and filled it through a carbon filter. The pH and Alk levels have been well balanced throughout. We use the tub every night we are home. The store recommended Best Defence - it ended up clouding the water quite a bit (Easy Clear wouldn't clarify) and it turns out that Best Defence was making the phosphates skyrocket (2500) We seem to be going through a filter every month as well. The water gets a little cloudy over time and replacing the filter seems to clear it up overnight. My questions - Is there a way to test the level of calcium in the water and what level should it be at? How do we control this? Up to now, the electrodes have been replaced under warranty but we did have to pay for one of the service calls. What else can we be doing to not have to replace the electrodes every 3 months? The store is now recommending Spa Perfect and the service line mentioned AquaFinesse. Thanks -- Scotte Quote
Nitro Posted August 25, 2009 Report Posted August 25, 2009 You can test the Calcium with the Taylor K-2006 drop test kit, among other important levels. Quote
quantumchromodynamics Posted August 26, 2009 Report Posted August 26, 2009 You need to test your tub water and your fill water. You can use a water softener on your fill line to remove calcium while filling the tub. I would keep the calcium at about 100 ppm for a fiberglass/plastic tub and higher for a concrete tub. Is your generator a chlorine or bromine generator? How much are you paying every time you need to replace the electrodes? Quote
quantumchromodynamics Posted August 28, 2009 Report Posted August 28, 2009 "Best Defense" is probably a phosphonic acid metal chelator/sequestrant. Phosphonic acid is an organic phosphate. If you use a phosphonic acid sequestrant, then you shouldn't use a monopersulfate shock because the monopersulfate will convert the organic phosphate into an orthophosphate. If you have high calcium or metals in your fill water then you should use a water softener to remove them while filling the tub. Quote
Challenger Posted October 27, 2009 Report Posted October 27, 2009 It's likely not anything you are doing. The Arctic Onzen system still has a ways to go before it is perfected. Right now the electrdes fail A LOT! They are constantly trying to revamp the system. Just hope that they figure it out soon. Until then replace electrodes when they stop working. Quote
ttrublue Posted October 27, 2009 Report Posted October 27, 2009 Turns out the Onzen system has a Tubby unit behind the blue cover. Quote
James Keirstead Posted November 2, 2009 Report Posted November 2, 2009 "Best Defense" is probably a phosphonic acid metal chelator/sequestrant. Phosphonic acid is an organic phosphate. If you use a phosphonic acid sequestrant, then you shouldn't use a monopersulfate shock because the monopersulfate will convert the organic phosphate into an orthophosphate. If you have high calcium or metals in your fill water then you should use a water softener to remove them while filling the tub. Hey quantumchromodynamics, You are correct "Best Defence" is a phosphonic acid compound. I am no chemist, but a hobby water chemistry nut. I am wondering if you could explain how monopersulfate converts the organic phosphate into an orthorphosphate and how that would impact the spa water. Also, what would be an acceptable alternative to monopersulfate to shock the spa weekly to remove chloramines and other organic contaminants? Thanks for the insight. James Quote
quantumchromodynamics Posted November 2, 2009 Report Posted November 2, 2009 An organic phosphonic acid sequestrant, such as HEDP (C2H8O7P2), can be oxidized to an orthophosphate PO4-3 by monopersulfate 1(and possibly by ozone and hydrogen peroxide as well). I'm not sure what the actual formula would be to describe the oxidation process. Once the phosphonic acid is oxidized, it is no longer effective at sequestering metals. Therefore, using a phosphonic acid based metal sequestrant and then shocking with monopersulfate is a waste of time and money. The metals should be removed from the water before adding the water to the tub if the metals are going to be a problem and the person wants to use MPS shock or ozone. If the water is exposed to sunlight, the phosphates could accelerate algae growth if the chlorine if not kept at sufficient levels. As long as the chlorine is kept at sufficient levels, then algae should not grow and phosphates are not going to accelerate algae growth. Another possible problem with high phosphate levels is that the phosphate can combine with the calcium in the water as Tricalcium phosphate - Ca3(PO4)2 or calcium phosphate CaHPO4. This can remove too much calcium from pools or hot tubs that need calcium. This might also cause scaling problems with salt cells Phosphates are used in some pH buffering products, such as pH Anchor and Perfect pH, and work in a similar way to carbonates, cyanurates and borates. However, they should not be used in water exposed to sunlight, water that needs a higher level of calcium or where a salt system is being used. Orthophosphoric acid (H3PO4) has a pKa1 of 2.16, a pKa2 of 7.21 and a pKa3 of 12.32. Therefore, at normal pool pH, the dominant species will be HPO4-2 HEDP (C2H8O7P2) I don't think that shocking is necessary if the chlorine is kept consistent and there is no combined chlorine. If shocking is necessary, I think that adding just enough bleach to oxidize the combined chlorine should be sufficient. Quote
toolmantoo Posted November 15, 2009 Report Posted November 15, 2009 Wow, that was awesome. The only problem is is I think I will have to go back to school and take chemistry to understand all of that. I guess being a hot tub owner means we should all have chemistry degrees. So should I be using Best Defence or shouldn't I because my water is becoming cloudy again. Is there another product to use to clear up my water. James if you are selling Arctic Spas, do you not have your own chemists and scientist to come up with a solution to your spa problems? Just wondering. Quote
James Keirstead Posted November 17, 2009 Report Posted November 17, 2009 Wow, that was awesome. The only problem is is I think I will have to go back to school and take chemistry to understand all of that. I guess being a hot tub owner means we should all have chemistry degrees. So should I be using Best Defence or shouldn't I because my water is becoming cloudy again. Is there another product to use to clear up my water. James if you are selling Arctic Spas, do you not have your own chemists and scientist to come up with a solution to your spa problems? Just wondering. Hey Toomantoo, I answered your other post on this. Keep me posted on how it is going. I am still confident that the solution is correct. :-) James Quote
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