Drwax

If your refiring to the Frog@ease product that will do it. Get away from that as fast as you can and drain your tub start over and go with good old chlorine. Balance in this order. Alkalinity followed by PH followed by Calcium hardness followed by chlorine. I had a similar problem but the specs were in my water floating around and along the walls of the tub. I finally decided to go with chlorine at the frog system was getting to expensive and it was not working anyways. Be sure to wait an hour or so in between adding chemicals maybe ever 2 or 3 hours.

Yes its a chemistry issue for sure. Prior to draining the tub buy some Oh Yuk cleaner, it will get rid of all the scaling then start over. You have to balance each chemical one at a time. Start with Alkalinity wait a couple hours then move on to PH wait a hour or so then move on to Calcium hardness wait an hour then finally add your sanitizer (Chlorine or Bromine whatever you choose). Once your calcium hardness is balanced you should not have to adjust that anymore until your next fill, just keep an eye on your Sanitizer mostly that's the one you will usually have to adjust. If your alkalinity is balanced it will help keep the PH balanced, they work hand in hand.

So its been a while since I posted and thought I should give a follow up for anyone else that may have experienced this issue. After several months of trying so many different things wondering if something was wrong with the parts on the hot tub it turned out to be exactly what most information out there would tell you, bad water chemistry. I was sold on the Frog@ease chemicals from my local pool store and from things I read on the internet, now this is by no means a bashing post against Frog@ease or their products but they just didn't work for me. I did a lot of research on spa chemicals and how to properly use them and what their functions are and decided to start with a clean fill and abandon the Frog@ease product and go with good old Chlorine. Before filling the tub I did the oh yuk cleaning solution 3 times over filling and draining just to make sure all the plumbing was super clean. On the last fill that I was going to keep after 20 minutes I noticed the black line coming back as dark as ever to my dismay, at this point I was convinced there was something wrong with an gasket or something but nope, turns out that our hose water in Tracy CA is just crappy dirty water! I started with just cleaning the ring and using a skimmer to get some small particles of dirt out of the tub, I then proceeded to test the water and adjust the chemicals. 1st you must only adjust the Alkalinity forget everything else, add what you need to increase or decrease so you get it at the right levels. After coming back 2 hours later my alkalinity was good , now I adjusted the PH. After an hour or 2 I came back and that was now good. I lastly adjusted the Calcium hardness and finally began adding chlorine. Over the next day I noticed the dirty water line had become very faint but I was adding chlorine daily as it was being used up killing the contaminants. after maybe 2 or 3 days the ring was completely gone and the chlorine had stabilized to where I was only adding maybe once every 4 or 5 days. Its been over a month and the ring has never come back and my tub have never looked better. The frog@ease was just not able to deal with our water I guess not to mention its pretty darn expensive compared to chlorine. I bought normal size bottle of chlorine and it will probably last me 6 to 9 months at the rate I am having to use it. Sorry for the long post bust just wanted to help someone like myself who convinced himself the hot tub was broken in reality it almost always come down to chemicals. Oh and pro tip I learned along the way, buy a hose filter it will help keep out a lot of the bad chemicals in the water and when you add chemicals heat up your tub prior to starting the process. Trying to balance your water while its cold with not give you the same readings when its full heated up. 🙂

LOL Thanks for all the help CST, all great info including that pic. Just for bleeps and giggles I monitored the tub for a couple hours after wiping away the dirt line around the tub and saw no return of the dirt, I then ran the tub with all the jets running for around 30 to 45 minutes and sure enough I started to see the line come back so its got to be one of the items your referring too or something close to that. Hey you have a great 4th and I will let you know how things turned out once I can get someone out here. Thanks again my friend.

Hi CST, Thanks so much for quick reply, really appreciate your advice! Were in northern CA, haven't seen any in a few months, don't think it has anything to do with rain as the dirt returned an hour after I filled the hot tub back up and it went through the prime and filtration. I Will for sure do the plumbing line cleaner though on the next fill. Tub is under warranty, so I may give them a call and have them check everything out. Don't think its chemical related as the Alkalinity, PH, water hardness, and smartchlor are all looking perfect on the test strip. I spoke to a friend who takes care of pools, he said he only saw something like this once before and it had to do with a plastic ring in the pump that was wearing and caused it.

Hi all, Thought I would stop by and see if anyone has seen something like this before. We bought our Hot Tub from Costco and received it 6 months ago. Everything worked great no issues, I an using the Frog@ease product to regulate the chemicals. Around the 3rd month of light use I saw this black ring of dirt show up around the tub, darker on one side then the other but it goes all the way around. Chemicals all read perfect on the test strips so I figured it was time to drain and give it a good cleaning since they recommend every 3 to 4 months anyways. Also I should note I have been taking the filter out every 2 weeks or so and squirting it down with a hose. So after draining the tub scrubbing away the ring that came off fairly easy, I filled the tub back up, did the shock treatment put in a new Frog@ease floater and within an hour the ring was back in full force. I even tried to remove the pillows to see if they were leaking some kind if dye in to the water but it came right back again. Wandering if there is something going on with the pump, leaking some kind of contaminate into the water? I have attached a few pictures.