4-week old spa, 4 weekends cleaning yellow-greenish "bubblegum"

[Biekske]

Hi there, my name is Bianca. I'm new to this forum and a new spa owner greenhorn. I'm having problems with cleaning. Using the spa or not does not make a difference in the yellow-greenish "bubblegum" lines that appear on the walls on the waterlines (load with 4, 2 or no person).
Please bear with me, I'm not a chemist and don't know the difference between chloride and chlorine in their different forms like granulate, tablets etc.. I only know that I use NaCl in my kitchen

Our spa was delivered 4 weeks ago, completely new. We filled it up, the technician ran some tests, shut the thing down, disconnected the electricity and in the next few days my husband built in a RVS heat exchanger from a secondhand central heating system (gas-driven), and filled the empty spaces between the frame, the tub and the floor plate with extra rockwool insulation. Now it only takes 5 minutes to heat up 1 degree Celsius on natural gas, which is the least expensive heating source over here.

But:

After using the spa about 4 times, a yellow-greenish "glue/bubblegum" layer appeared on the high, middle and low waterlines (4 people load, 2 people load and empty). So we emptied and cleaned and flushed the system... Takes almost a full day and tons of waters, but okay.
We've been cleaning and filling and cleaning and filling every weekend since.... But once the water level is high enough, and the heat has reached 32C, the bubblegum lines reappear.

All readings from the test strips (came with the spa) are good, over and over again. Our local tab water is the best in the Netherlands, German Hardness less than 3. But we put 2 chlori-thingy tabs on the tray as soon as we see the old ones have dissolved, just to be safe. Our tab water has a light green transparent hue. We use chlori-thingy granulate to shock, but the manual does not recommend that when using the chlori-other-thingy tabs. The packages do not indicate any specifics about concentrations of chlori-thingy, nor is there any mention about the type of chlori-thingy or something else. But up till now we have not seen an indication on the strips that we are doing it wrong. One simple unloaded run and the readings are just fine, within the safe perimeters...

Can someone please explain what this "bubblegum" is and how we can get rid of it? It costs us 2800 liters of fresh water every weekend cleaning the tub!

Thanks so much for "listening".

Greetings from Noord-Brabant, the Netherlands.

PS: Vendor/importer has been unresponsive and shown himself to be an absolute ignorant where alternative heating sources is concerned AFTER the sale....

 

[JVTrain]

How have you flushed the spa system when doing so? You should use a powerful surfactant that's designed to deep clean the spa plumbing. The best you can get is a product called Ahh-some. It thoroughly cleans bio-films from spa plumbing like nothing else. See if you can get it online or have it ordered. Ahh-Some Water Cleanser, for pool, hut tub, jet bath, and washing machines

Check out the How do I use Chlorine in my Spa (or pool)?) and How do I use Bromine in my spa (or pool)?) for our recommendations on how to sanitize your spa. Everything you need to know is in there. However, I realize that in the Netherlands, you may not be able to reliably get bleach if you're going with the chlorine method. I'm also not sure on the availability of bromine products. Generally, using trichlor tablets, as I am assuming that is what you are using, is not recommended for long term use in spas. Read through both of those threads that I linked as well as ABCs of Pool Water Chemistry to get the idea.

I would try to get a test kit that is based on liquid drops. I'm not sure what is available but a 3-way drop-based test kit for pH and total chlorine/bromine would be better.

 

[pabeader]

We have a few other members from The Netherlands. Maybe they can suggest some things. One of them is edwin2014

another is: edwin45

 

[Edwin45]

Hello Bianca,
i,m from The netherlands, clean jour spa with tube clean, iT is The strongest we have in Holland.
then follow The dichloor bleach methode.

using poolmath iT is calculator on The forum, for how much jou most put in.

Here is a quick reference to using the Dichlor/Bleach method. (i.e. Chlorine)

Please see the full guide for a detailed explanation. Top link below.

Initial Startup Procedure
1. Balance water by lowering TA to ~80 ppm. See link below (Lowering TA)
2. Aerate until pH is consistently 7.4-7.8. Lower TA if pH rises above 7.8. Raise TA if pH stays below 7.4.
3. Test Calcium, and make note of it. (100-150 ppm) is ok.
4. Add 50ppm Borates (highly recommended)
5. Shock tub to 10 ppm FC using Dichlor the first night after filling.
6. Wait 24 hours and test FC again in order to calculate Chlorine Demand. (See link below)
7. Start using tub.
8. Continue to use Dichlor after soaks (approx 7 ppm FC per person per hour) (or 3.5 tsp)
9. After you have added ~34 ppm FC (~30 ppm CYA) using Dichlor, switch to Clorox 6% unscented bleach. Takes about a week or so.

Ongoing Maintenance
After the initial startup procedure above, you'll basically do the following:
Check FC every day or two (and before soaks).
Check CD as needed (once a week to start).
Add plenty of Chlorine after soaks (and as needed) so FC NEVER drops to zero, and CD stays low.
Add MPS before/during high bather loads to help out the Chlorine, and keep CD low. (Optional but recommended)
Check pH once a week, and adjust TA as needed.
Rinse filter every week or two, depending on use.
Check CYA every 3 months, and raise by using Dichor if needed. CYA will drop slowly over time.
Use Sea Klear (clarifier) if you experience foam, or cloudy water.

 

[Edwin45]

i,m testing my water with Scuba 2 we don,t have beter in The netherlands.

 

[Edwin45]

Search also on Natriumhypochloride 12,5 iT is chloor

 

[chem geek]

Just note that for the Dichlor-then-bleach method, you usually need to lower the TA lower to 50 ppm (not 80 ppm) in order to have more pH stability (with the 50 ppm Borates that are pretty much required) especially if you use spa jets.