Hot Tub Feels Like Sandpaper

[blindrid]

I've had tubs for a long time. Last night went in and tub felt very rough. I just cleaned it last month, adding calcium to bring up the hardness levels to acceptable levels. My norm is to get the PH correct when I fill and after that, there is little maintenance.

First of all, what causes the roughness as some of my google searches indicate calcium precipitate from a bad PH level. Does that sound right to the pro's in here? If so, how is the best way to remove. Water is clear, use bromine floater, use very little and shock once a week.

Your help is appreciated. Thanks, Randy

[waterbear]

combination of high pH, high TA and high Calcium hardness. If you would post a full set of test results it would tell us a lot more.When you fill the tub do you add sodium bromide to create a bromide reserve in the water? What are you using to shock, MPS or chlorine?

[blindrid]

I'll test it again tonight as I can't remember the particulars. I do remember the hardness was about 200, the bromine showed fine. I do add a sodium bromide when I fill and I typically shock with chlorine.

[waterbear]

So, do you have those test results yet? Or better, a test result history for the past month? THAT would tell us a lot. Also, how do you test the water?

[blindrid]

Hardness: 250

Total bromine: 2

PH: 6.8 reduced with ph down last night from about 7.2

TA: 80 (now)

Added fresh water last month not used until last week a few times.

No history as I've never had problems.

test with strips

It seems like it may be clearing up or my imagination is kicking in wishfully.

Thank you

[waterbear]

What was the TA before? If the lower pH is dissolving it then it was a scale deposit from improper water balance (most likely a combination of high TA and high calcium hardness--btw strips are useless since they only test total hardness andthat does not tell us much). A pH spike will cause calcium carbonate to precipitate under these conditions and it can deposit on the walls of the spa, making it feel rough.

The fact that this happened indicates that you do have water balance issues (and probably water testing issues) so you might want to review the basics of bromine chemistry. and invest in a decent test kit (for bromine the Taylor K-2106 is the best for the money).

Also, a bromine level of 2 is really too low. I would not let it drop below 3 ppm as a bare minimum if the tub is not being used at all and 4-6 ppm is a comfortable range for normal usage.

[blindrid]

Thanks. I do have ozone so is the bromine level of 2 still too low? My goal is to get the deposits off the tub (and assuming the heater and pump) and then drain the tub, clean the filters and start fresh. It's only a 300 gallon tub so it's not a huge issue to drain and clean. Is there any chemical flushes that would help before I drain it?

I'll check the roughness again tonight and let you know. As to using strips, I've been negligent is getting a test kit as that's been on my "to do" list for some time. I think you have finally pushed me into buying one.

Thanks for your help and I'll repost the status this evening.

[waterbear]

Thanks. I do have ozone so is the bromine level of 2 still too low?

Yes, ozone does not allow you to run a lower bromine level If you were using chlorine then bromine MIGHT allow you to use a lower total amount of chlorine to achieve the same free chlorine residual as without by oxidizing some of the bather waste so the chlorine does not get used up doing so but ozone destroys chlorine so it is very possible that ozone can actually INCREASE the amount of chlorine needed.

In a bromine spa, ozone simply oxidizes the bromide in the water into bromine sanitizer just like MPS and chlorine do. (and also into non renewable bromate so it can deplete the bromide reserve faster and require more frequent water changes). It does not allow you to run a lower bromine level. It might allow you to need less oxidizer to maintain the bromine level or allow the floater to be set at a lower setting but the required residual level in the water does not change.

The lucky thing is that most ozone installations in residential spas are more of a marketing tool and really do not do much at all so it is often a moot point.

[blindrid]

Thanks. I do have ozone so is the bromine level of 2 still too low?

The lucky thing is that most ozone installations in residential spas are more of a marketing tool and really do not do much at all so it is often a moot point.

That's what I always figured but was never sure. I didn't get out there last night with severe rain and a few inches of hail. I'll get out there tonight and revise the #'s and see if the residue is dissipating or not.

Thanks for yout time on this.

[blindrid]

Hi Village. My ph popped up to about 7.8! The tub is still pretty rough so I added ph down a few minutes ago. I'm was hoping to clear up the roughness so I could change water this weekend. Is it asking too much for the rough surface to clear up?

[blindrid]

Any thoughts?

[waterbear]

One big problem is testing with strips. They are pretty useless for water balance issues and we still don't know what your calcium harndess is since strips cannot test for it, only total hardness.

Without good test results it's next to impossible to solve the problem. Even your TA results are suspect since strips have a resoluton of 40 ppm on the TA test and that is just too wide a window to do anything meaningful with.

If you could get some dependable test results it would help.

In fact, if you had dependable test results you probably would not have had this problem to begin with. I has asked you earlier for the TA before you lowered it to 80 ppm by the strips and you never answered. Therefore I am assuming that you did not know and have not been regularly testing your water.

My suggestion would be to get a good test kit that includes an acid demand test which will make it easy to keep your pH at around 7.0 to 7.2 to help dissolve the scale over time and also to get good readings on TA and CH so we know why it is happening. My suggestion is a Taylor K-2106 for bromine.

[blindrid]

Obviously, you do not read the posts. I do not write down or remember any prior tests. My question ultimately was what I needed to do to get rid of the roughness / scale so I could drain the tub. In over 20 years of owning a tub, I have never had the problem and don't anticipate having it again with fresh water.

As mentioned, the answer was not given so I was forced to give up without the information you claim you need as you sell another test kit. I've gotten along fine with strips over the twenty years and plan on for the next twenty.

[waterbear]

Obviously, you do not read the posts. I do not write down or remember any prior tests. My question ultimately was what I needed to do to get rid of the roughness / scale so I could drain the tub. In over 20 years of owning a tub, I have never had the problem and don't anticipate having it again with fresh water.

As mentioned, the answer was not given so I was forced to give up without the information you claim you need as you sell another test kit. I've gotten along fine with strips over the twenty years and plan on for the next twenty.

I do read the posts but you don't seem to . I answered your question here:

My suggestion would be to get a good test kit that includes an acid demand test which will make it easy to keep your pH at around 7.0 to 7.2 to help dissolve the scale over time and also to get good readings on TA and CH so we know why it is happening. My suggestion is a Taylor K-2106 for bromine.

I told you that if you use an acid demand test to keep your pH at around 7.0 to 7.2 for an extended period (it will continually rise because of the aeration of the jets cause CO2 to outgass and your TA will drop also so monitoring the water is important) then the scale will dissolve. This pH level is withing acceptable range but lower is not which is why an acid demand test is a useful tool. My test kit suggestion is the most cost effective one for a bromine tub which is why I suggested it.

I do not sell test kits and for that matter am not currently employed in the pool/spa industry so I have no vested interests.

Your problem is a water balance issue and test strips do not have the resolution needed to balance water (the TA test has a resolution of 40 ppm and there is no calcium harndess test, only a total hardness test, which is useless. Scaling conditons usually occur at higher pH, particularly with the hot water in a spa (I won't go into the calcum saturation index calculatons since it will be above your head.) You are lucky that you have not had problems in the past but guess what, you have them now and were told how to solve this particular one. Also, if your fill water has changed recently (guess what, water from utility companies and wells will change in water composition such as calcium and total alkalinity and pH at different points in time or because of different water treatment techniques or ground water conditions ) you will possibly continue to have this problem. Without good test results there is not much anyone can do . I told you how to solve the problem but you don't want to listen so Good Luck to you.