ahh-some purge yesterday, some film above water line today

[M1KE]

I received a hot tub (2013 coyote laredo) with the purchase of my house and have finally got around to taking care of it. I had a local pool/spa guy come out and do a purge (he used some name-brand spa purge), drain, and fill. The water looked clear and great, but unfortunately the levels weren't right (pH always 8+) so I decided to figure it out on my own. After some playing with the chemistries, I gave up and figured I needed to start from scratch and do it myself to make sure it's right from the start (truth is, I just didn't know enough to get it right, but I started over anyways).

So yesterday I followed the decontamination procedure I found on another forum using ahh-some to purge and then high levels of bleach to kill everything. I didn't drain in between the purge and bleach parts since we are in a drought-restricted area, but felt like we got it good enough. There wasn't very much biofilm that came out (especially compared to some of the posts I've seen), which made me feel good about the initial work the local guy did. We filled it up, I spent all of last night reading the forum and trying to get the water balanced (I have very different water here than what I see from others), but I finally got everything balanced (pH: 7.6, TA: 50, CH: 200) and so I added in some bromine granules, MPS, and my floater with bromine tabs and went to bed.

I went out today (about 14 hours later) to check the bromine level (which was 20ppm, I definitely added too much MPS I guess) and I noticed a bit of dark green/black biofilm (same as what came out yesterday) built up in a couple places right above the water line. There wasn't a lot, just a bit around one jet and two lines each about 6 inches long. At this point, I'm not sure if I should be concerned or if this is normal following a good purge. Could I have awaken the biofilm beast and now I am getting it spreading around and growing on the tub? Or is this just some that got knocked loose and never got flushed out, but is harmless and dead? We never saw any trace of anything after the purge from the local pool guy, but then again, ahh-some works way better than anything he would have used. What do you guys usually see after a purge? Is there residual for the next day or two? We wiped it all off with bleach and will be monitoring it (and unfortunately staying out of the tub) until we figure out what to do.

Also, before anyone asks - yes, I'm using a Taylor kit (2106) for my testing.

 

[Mdragger88]

It’s probably fine - just a little residual stuff being expelled. Keep your sanitizer up & wipe it with a rag if it reappears. You may wanna rinse your filters off again.
This is why i purge with the recommended amount at shock level for about an hour then let the tub rest after everything has dissipated & no more bubbles) then i add another 1/2 dose & go again (same water) before draining & refilling. Also Some people are able to refill a little & “burp” the lines then drain that but I cannot in my tub so i just put the hose in the filter/intake area & let water run via gravity out of the jets to rinse them for a couple minutes then i drain that “rinse” water & refill

 

[Ahhsomeguy]

Hi M1ke: Based on what you are saying it seems like this is simply residual bio-gunk. When you drain the tub after purging some of the released biofilms in the water drain back into the plumbing system. After a refill you start the jets and sometimes will get another small discharge. Just wipe it up and all is good. Your comment about awakening the beast is not far from the truth. Many times a purge is completed and after refilling there is another big release of biofilm into the tub. This is usually because the initial purge was not as effective as needed or that the purge product was still penetrating into the slime layer where the biofilm hides but the purge ended just prior to it's removal. Then, you drain and refill and when the pump starts the flow of water pushes it out into the tub proper. Happens quite often. Mdragger88 adds another 1/2 dose of the Ahh-Some after the initial purge has been completed into the same dirty water to facilitate the removal,of even more hard to get gunk. Biofilms are very Well protected inside plumbing. They can harbor themselves deep within a thick matrix of hard to penetrate layers. This is also why we explain to people that after the initial purge we recommend that you wipe up all the released sticky stuff so it doesn't dry and adhere to the shell, let the tub set with no water movement for 5 minutes and then turn the jets on for a minute, shut them off, turn them on, shut them off and so on. Any "clingers"should be pushed out after doing this. Hope this helps.

 

[Newdude]

Mine didn’t start purging until the 3rd round. It was that rooted. The first one produced nothing and the second was just a little. I figured it was done and ran a third expecting it to be clean and that’s when the magic happened. Then it took 10 (?) rounds to get it all. I didn’t drain each time and did 2 or 3 rounds per fill. I understand if you don’t want to start over, but next time plan on purging several times just to be sure.

 

[M1KE]

Thank you all for the replies and information. I went out today and checked several times and never saw any additional build-up along the water line. I really thought I was thorough since I added the ahh-some, ran jets for 30 minutes, let things calm down, and then added bleach and ran for another 40 minutes or so on the same fill. After reading Newdude's reply, I'm now afraid I may have just been scratching the surface
I'll definitely be following everyone's advice next time around, I really want to be able to enjoy this tub (still haven't even got in it) and not have any safety worries in the back of my mind. For now, I am still waiting for my bromine levels to come down.. still 16.25ppm when I tested earlier today.