Bio film in hot tub

[deenamccauley]

Has anyone dealt with bio film (at least I am assuming that is what the white film covering my hot tub was).
I'm sure it's my own fault because I got busy and did not stay on top of the chemisty in the hot tub.
Although it was never without sanitizer, the PH and alkalinity were out of whack. Both quite high.
Last numbers were
Bromine 12
PH 10
Alk 250
What I am wondering is, is this something that can live in an empty hot tub for a period of time?
I'm not sure where I went wrong, it wasn't till I switched to Bromine that I started having issues.
My problem was I was using a chlorine feeder in between using liquid chlorine, just to keep the numbers up but I could not get unstabalized chlorine tablets so the CYA level just kept getting higher. I have an indoor hot tub so didn't really need a CYA level.
Any thoughts would be appreciated.

 

[Guest]

Last numbers were
Bromine 12
PH 10
Alk 250

How was this tested. These numbers look a bit strange, especially the pH of 10 which is EXTREMELY alkaline and would be corrosive to anyone soaking in the tub! (and also difficult to imagine in a bromine system since bromine is acidic)

 

[deenamccauley]

I used my Color Q tester.
Now I must say that when I compare the Color Q to my Taylor test kit there always is a difference but not enough to be alarming.
I had trouble with high PH from the time I started using the Bromine. It was consistantly in the 8's despite my treating it with PH Minus usually twice a day. The alkalinty was usually on the low side until the last week when the bio film (?) appeared and that is when it skyrocketed.

 

[Guest]

I used my Color Q tester.
Now I must say that when I compare the Color Q to my Taylor test kit there always is a difference but not enough to be alarming.
I had trouble with high PH from the time I started using the Bromine. It was consistantly in the 8's despite my treating it with PH Minus usually twice a day. The alkalinty was usually on the low side until the last week when the bio film (?) appeared and that is when it skyrocketed.

Was the pH test turning a dark purple color? if so you did not have a valid pH reading but were getting interference from having your bromine levels too high!

 

[deenamccauley]

Actually it did not turn purple. It was red. I did take the high bromine into account but even when the bromine levels were normal I had high PH.
I understand the areation can account for high PH and low Alk.....so I was surprised wth the Alk reading skyrocketed.
I did shock it a couple of times with bleach 6% when I noticed the film start thus the high levels.....but nothing seemed to be working on this film.
So seeming as we were shuttung it down for the summer, I just decided to drain it and clean it.
I just wonder if this is something I have to be careful of when I restart it in the fall? Can it live in a dry tub over a period of time?

 

[Guest]

Does it (the biofilm) look like wet tissue paper and does it break apart easily?

 

[deenamccauley]

It really wasn't like tissue paper. It was a thin film over every surface. It could be wiped off fairly easily and then of course the water was cloudy for awhile.
I wish I would have taken a picture, I've never seen anything like it. Course I haven't seen much in the way of algae or anything like that because I've never had that problem, eithr in the pool or the hot tub.
I did notice that it was under the jets,etc....and that was my concern that if it's there it's in the pipes too.
And if shocking it didn't even touch it, I'm worried I may have issues later.

 

[Guest]

Your alk is 250 which is way too high, what is your calcium hardness? With your high pH it could just be calcium carbonate. Why not post a full set of test results.

 

[deenamccauley]

Well the problem with that is that there is no longer water in the hot tub. I drained it.
The last CH was 190 which was taken at least a week before all this happened.
It did almost seem like a residue on the tub, it stayed there even after it was drained.
I did not have to rub hard to get it off but it certainly didn't just wash away when the tub ws drained.
Can you explain to me what exactly calcium carbonate is, does and why it would accumulate like that so I don't repeat this mistake.
Thanks so much for taking the time to answer my questions.

 

[Guest]

Well the problem with that is that there is no longer water in the hot tub. I drained it.
The last CH was 190 which was taken at least a week before all this happened.
It did almost seem like a residue on the tub, it stayed there even after it was drained.
I did not have to rub hard to get it off but it certainly didn't just wash away when the tub ws drained.
Can you explain to me what exactly calcium carbonate is, does and why it would accumulate like that so I don't repeat this mistake.
Thanks so much for taking the time to answer my questions.

When TA and calcium are high and pH is also high the calcium and the calcium will precipitate out of the water as calcium carbonate (the carbonate is part of the TA. Another name for TA is carbonate hardness, it is actually made of bicarbonates and carbonates in the wate). This is also called scale. It is why adding baking soda to a pool with high calcium can cloud the water or adding calcium or using cal hypo in a pool with high TA will cloud the water. The higher the pH the more likely this is to happen.
The way to avoid it is to keep the TA within recommended range (for bromine around 100 ppm) and not let the pH spike high. Getting the TA down will help with the pH, btw.

 

[deenamccauley]

Thanks for all your help.
I'm still not clear why the alkalinity would suddenly skyrocket when it was consistantly low over the winter. But I am glad to hear that it's probably not anything that will give me a problem when I restart it in the fall.
I will take care to not let that happen again.
I appreciate all your help.