Spa odor

[Blake106]

I’m maintaining this commercial spa that gives off a combined chlorine smell, when I test I see that the total chlorine is the same as free chlorine meaning there shouldn’t be combined chlorine (using Taylor k-2005). I continuously maintain the proper fc to cya ratio. I do a drain and refill every two weeks to make sure cya doesn’t go off the charts because there’s a trichlor tab feeder. Just a couple days after the refill I’ll start to get the smell again. Should I just accept that public pools and spas might sometimes give off weird smells even with no detected cc? It’s inground, 1,800 gallons with no cover. Any chance it could be biofilm in the plumbing? Pipe diameter and sand filter are the same size used for 20,000 gallon pools, not even sure if a spa purge product would be applicable for that.

FC-5 in morning peaks to about 8-10
pH-7.5 to 7.8
Cya-60
Ch-180
Ta-100 to 120
Temp-103 to 104f

Thank you.

 

[Ahhsomeguy]

Hi Blake: Question: Have you ever performed a plumbing purge? Based on your post I assume you have not done so. Your water chemical numbers look fine which indicates that you are on top of it. I would bet that your vessel’s plumbing and filter sand has a decent accumulation of biofilm As well. Commercial tubs are notorious for Biofilms. Biofilms can smell. This could be a source for your malodors. Here’s what you do Blake. Shut that unit down at the end of a day, add an effective purge product to the filled and heated water. Keep the sand filter on the “filter mode” during the purge. Assuming your spa has a tile and grout top border be sure to wipe all the brownish gunk you will see start sticking to the tile During the process. Be sure to wear latex gloves while wiping. After running the purge for 30-45 minutes shut filter off. Drain the spa while rinsing and wiping noticeable gunk. Please note: You will see discoloration on the grout that will be hard to wipe off. Don’t worry about it. When you refill the spa and the sanitizer is added this will lift off and the filter will grab it very quickly. Not sure what purge product you will use. They all seem to work somewhat but I obviously would recommend the Ahh-Some Hot Tub product as we know what it can and will do for you. if you use the Ahh-Some you will need to use an entire 2 ounce container or 12 teaspoons for one purge. You will notice foaming. Let it foam. Foam is your friend while purging. You may want to wipe any sticky clinging brownish yellow gunk off any stainless or plastic escutcheons using a water/vinegar dilution on a rag When the spa is empty. Refill and backwash the filter again BEFORE filtering the new water. Your next maintenance purge will go much quicker providing you do this every 3-6 months or so. Plus, on subsequent purges you can use only 8 level teaspoons instead of 12. If your spa has the amount of biofilm I suspect you may have, you are very fortunate that there have been no incidents. Commercial spas that are not maintained properly and not bio-purged on a regular basis can be a real area of concern. Good luck with the purge Blake. Please let this forum know how it goes and if this solves the smell issue. You will now have clearer water and not have to use as much sanitizer until the biofilm builds up again.

 

[Blake106]

No, I have never done a purge, I’ve been working there for a little over two years and have a feeling that nobody else ever has done it before me. Just ordered a 6oz tub of ahh some last night. I’ll do the process next week and will report back how it goes. Thank you for the detailed response. Also, is there any such thing as purging plumbing that may or may not have an excessive biofilm build up for a pool? I’ve never heard of it and was wondering why a hot tub would need it and not a pool.

 

[Ahhsomeguy]

Blake: Swimming pools have biofilm. The difference is that the surface area is much greater and not as noticeable as in a smaller vessel. Biofilm is everywhere where water or moisture touches. Our very first product, over 15 years ago, was our Pool Bio-Cleaner & Water Clarifier. That product enjoys tremendous popularity. Once the pool owner adds it for a minimum of two-three months they won’t go without it. For some commercial pools we usually offer this in larger containers which save them money. Why don’t you just get your spa treated first and we can go from there.

 

[Ahhsomeguy]

Blake106: I do hope you see this post. I was thinking about you saying that this commercial spa has probably not had the plumbing purged in years or possibly ever. Whew! If that’s the case you are in for a unbelievable sight. I want to make sure you fully understand how to accomplish the best purge for that vessel. Be sure there is a free chlorine reading just prior to adding the 12 level teaspoons of blue gel. Run the filter with the selector valve on filter For 30-45 minutes with all the air intakes open and blower ( if equipped) on after you add the gel. We want turbulence. Wipe, wipe and rewipe the sticky goldfish brown goo with a old towel while wearing gloves. After 45 minutes I want you to shut the pump off and add 4 more level teaspoons of gel to the same dirty water. Run for an additional 10 minutes. If you still keep getting more and more gunk released I want you to add 2 more teaspoons and run for another 10 minutes. All this run time is with filter on and air intakes open. At this point, if you are still seeing new biofilm being released into the spa I want you to wipe the top waterline area to remove the gunk. Shut the system down and let the water set for 30 minutes. Then, run the filter for a minute, shut it offf, run it for another minute and then shut it off. Now, drain the spa. Hopefully you have a submersible pump. Rinse the tile and surface as it drains to knock off the gunk that may be sticking to the shell. I assume the spa has a marcite with tile finish. You may be able to turn your filter valve to the WASTE position to drain the spa more quickly ( NOT BACKWASH ). Be sure to turn skimmer or top suction valve(s) off so you only suck from the main drain of the spa. When you refill the spa the filter should be backwashed for 1-2 minutes before you place selector back to filter cycle. So, fill the spa and backwash the filter. You must backwash before you go to filter cycle to get rid of the gunk collected in your sand bed. You probably know this but it is very important that you never move the filter selector valve to any other setting with the pump on. Always shut it off before moving filter valve. Balance the water to the same numbers you list in your first post. You should be good to go. Please report back with what you noticed and how the water is now after the purge. The next purge needs only 8 level teaspoons and you should purge that spa every 3 months or so. The next purge will go faster as you will just need a 15-20 minute purge to do the job. It’s easy to do. Have fun!

 

[dan1333]

When you do the purge please take pics and keep us updated. I think the biofilm slime released will be impressive!!

 

[Blake106]

Did the purge today. Decent amount of light brown collected on the tile line, looked average from other hot tub purges I’ve seen. Nothing too crazy. I feel like most of the product collected in the filter (not a bad thing) before it was able to do work in the pipes. I have a separate pump and plumbing dedicated just for the jets so there are four main drains in the spa. I feel like most of it got sucked through the main drains for the filter and got trapped in there and did the work there, (idk if that would make sense) and not enough for the jet lines. You think next time I should put the multiport before the filter on recirculate instead? It’s my bad for not stating I have separate pumps and plumbing for the filter and jets.

 

[Ahhsomeguy]

Glad it seemed to get the gunk released Blake. The first time I wanted your sand filter to grab some of the gunk. Be sure to backwash completely, no more than 2 minutes though. If you backwash for 2 minutes and are still getting a discolored and generous amount of gunk out the backwash line I want you to shut the pump off, go to the Rinse position, turn the pump on for 30 seconds, shut the pump off, switch back to Backwash and run the pump for another minute or so. Then, shut the pump off, go back to Rinse Valve position, turn pump on for 30:seconds,shut pump,off, go to Filter Position and turn pump on. You may still get a “burst” of discolored water out the jets but the filter will get this in time. You may also need to wipe the tile line for a day or so periodically. Now, your work will pay off. Let’s see if the bad aroma goes away or gets less obnoxious. Be sure to balance the water like you did before you purged. Those numbers were very good as I remember. Please report back to us as to the water clarity and whether the maintenance is easier. I do believe that your filter gobbled up a significant amount of bio-gunk as you have indicated.

 

[Blake106]

Glad it seemed to get the gunk released Blake. The first time I wanted your sand filter to grab some of the gunk. Be sure to backwash completely, no more than 2 minutes though. If you backwash for 2 minutes and are still getting a discolored and generous amount of gunk out the backwash line I want you to shut the pump off, go to the Rinse position, turn the pump on for 30 seconds, shut the pump off, switch back to Backwash and run the pump for another minute or so. Then, shut the pump off, go back to Rinse Valve position, turn pump on for 30:seconds,shut pump,off, go to Filter Position and turn pump on. You may still get a “burst” of discolored water out the jets but the filter will get this in time. You may also need to wipe the tile line for a day or so periodically. Now, your work will pay off. Let’s see if the bad aroma goes away or gets less obnoxious. Be sure to balance the water like you did before you purged. Those numbers were very good as I remember. Please report back to us as to the water clarity and whether the maintenance is easier. I do believe that your filter gobbled up a significant amount of bio-gunk as you have indicated.

Ok thank you.