I can't keep calcium buildup out of hot tub. Help!

[Leslie]

I wonder if anyone might be able to offer suggestions for a longstanding problem with my hottub.

There are tiny crystals on the inside of my hottub.  I have been told they are calcium and to add 6-8 gallons

of vinegar to water (which removes the crystals) and then to drain the tub.  I have probably done this at least 10 times now.

Each time I drain the tub down, put in fresh water (not well or watersoftener water).  The sides are clean with no crystals

for about a day, then by day 2, the crystals are back on the walls.  I add vinegar, they dissappear, I drain, refill, they come back.

 

Also tried adding spa purge as someone recommended, actually tried this twice this past week.  But that has not solved the problem

either.

Any other ideas, this is so frustrating, as I just don't know what to do.  The hottub just sits unused due to the crystals.

I took a sample of the water I fill with and had it tested. The calcium in it is 180.  Also I use the leisure brand of chemicals which includes stain and scale preventer.

Thanks for any help

Leslie

[Chas]

There is a thing called "Balancing your water." What you do is to add some form of acid to lower the pH. But once you get the water balanced, you certainly don't drain the thing!! If it takes that much vinegar to drop the pH to 7.4 and the TA to 100, then add it. I would be shocked if it does take that much for a simple water change though: I have a 500 gallon tub and I add about 4 dry ounces of "Spa Down," which is a dry acid. I usually have to add about another two ounces the following day, but then the tub is balanced and ready to enjoy.

If your source water is high in pH and TA, you will ALWAYS have calcium precipitating out onto surfaces until you lower that pH and TA, and keep it in line. If you have the 'sandpaper' feeling, you will have to lower the pH to around 6.8. Don't go lower than that - and keep it there for several days. That will allow the calcium to ease back into the water, which is right where it came from. You do NOT have to change the water once this is done, you only have to keep the pH at about 7.4 from then on and the problem will be gone. If you get the calcium back into solution and then drain/refill, you will simply perpetuate the cycle. Stop the madness! 

The big problem with calcium build-up is with heating equipment and the tubing - places where you cannot see the build-up: you can eat a heater alive with what you are doing. But if you drop the pH to ridiculous levels, you can damage them as well.

One more thing: don't drain the water while there is a lot of calcium on the walls/floor. Putting in new water and then trying to coax that calcium into the new water is tough: it comes in with it's own load of calcium and now you are trying to get it to hold more.

OK - one MORE more thing: don't think of balancing the water as "adding chemicals to my spa." What you are doing is balancing the chems which are there from the tap. Instead of thinking of 'adding acid,' think of 'neutralizing the alkali' in your source water.

Again with the 'One more thing:' after you add anything to change your pH/TA do NOT retest for at least six hours. The pH will go way down and then come back to it's new level and if you test right away you will panic...

HTH

 

[Leslie]

Thanks I will try the lowering of the ph like you said to 6.8 for a few days after i go out and fill it again.  Sorry to sound so naive about it,  Ive had this tub running with no problems for about three years.
Started having foaming problems, was told to add calcium (lots). Then after I started having sandy feel, I was told by my spa dealer to add the vinegar to draw the calcium back into water, then drain.  So I kept being told to do that each time I asked for more advice. Hope I haven't ruined my tub.  So far all jets and heater work, though my tub doesn't drain. Maybe that's clogged.

My current regimen is fill tub with water and add metal gon during fill.
Next I balance ph and TA.  After this is done, I add a bromine reserve and shock. The bromine products are both powders.  The products I use are leisure time brand.

Then weekly maintenance includes checking ph, and adding something for enzymes, a scale preventer, and bright and clear(says it neutralizes and removes particles).  I also add more bromine after we use tub.  The  tub also has an ozonator. 

Any more thoughts on my maintenance. I'm open because it doesn't seem I've had very good advice so far.  Also, as an FYI, each time I have added new water, I can get it balanced in terms of ph, etc.  the sides still get coated.  So I am really hoping your recommendation of leaving water in,lowering ph to 6.8 for few days will do the trick.

Thank you so very much
Wish me luck!!! 

Leslie

[TwinCitiesHotSpring]

drain spa, "glove up" and use a 50/50 water/muriatic acid ratio to scrub as much of the existing calcium out of every nook and cranny...then follow the post above and re-fill and balance water..a good calcium level is right around 150ppm

[Leslie]

Thanks, but the sides of the tub are currently clean, they are clean because I added the vinegar before I drained it.  I just need to figure out how to keep it from returning each time.

[TwinCitiesHotSpring]

Thanks, but the sides of the tub are currently clean, they are clean because I added the vinegar before I drained it.  I just need to figure out how to keep it from returning each time.

to keep it from returning you need to drain and clean all nooks and cranny's as I described, and start off with a 150ppm (approximate) calcium level

[Chas]

I don't agree - acid washing a spa is not as effective as simply lowering the pH and TA over a period of time because the water will clear out the plumbing as well as all nooks and crannies that you can reach by hand. And since you have said that adding vinegar (which lowers the pH and TA) has cleared it out already, I would not do an 'acid wash.' Not to mention what it does to some finishes, like polished stainless steel, chrome, and some headrest pillows. 

You mentioned that you have added 'lots' of calcium to end a foaming problem... let's look at that. If you have foam, it could be due to things being introduced into your water that cause it to foam. Swimsuits which are laundered are the prime culprit - rinse only but do not wash - and then hair products, lotions, guests who do not own hot tubs, etc. Soft water makes it far worse, so your dealer may have been trying to help by adding calcium to raise the softness level. First - try filling with hard water if you have a choice. By that I mean: if you have been filling your tub with softened water, try filling from another faucet/spigot with hard water. If ALL of your water happens to be very soft, then add only enough calcium to bring the level of hardness up a bit.

But you can also fight foam by keeping the sources of foam out of your spa, or by adding a de-foamer. In any case, don't let the pH and TA get above normal and you should not see the calcium come out of solution. That fallout of calcium only happens when the pH and TA climb and stay up.

HTH

 

[TwinCitiesHotSpring]

I don't agree - acid washing a spa is not as effective as simply lowering the pH and TA over a period of time because the water will clear out the plumbing as well as all nooks and crannies that you can reach by hand. And since you have said that adding vinegar (which lowers the pH and TA) has cleared it out already, I would not do an 'acid wash.' Not to mention what it does to some finishes, like polished stainless steel, chrome, and some headrest pillows. 

You mentioned that you have added 'lots' of calcium to end a foaming problem... let's look at that. If you have foam, it could be due to things being introduced into your water that cause it to foam. Swimsuits which are laundered are the prime culprit - rinse only but do not wash - and then hair products, lotions, guests who do not own hot tubs, etc. Soft water makes it far worse, so your dealer may have been trying to help by adding calcium to raise the softness level. First - try filling with hard water if you have a choice. By that I mean: if you have been filling your tub with softened water, try filling from another faucet/spigot with hard water. If ALL of your water happens to be very soft, then add only enough calcium to bring the level of hardness up a bit.

But you can also fight foam by keeping the sources of foam out of your spa, or by adding a de-foamer. In any case, don't let the pH and TA get above normal and you should not see the calcium come out of solution. That fallout of calcium only happens when the pH and TA climb and stay up.

HTH

 

you misunderstood my point, if calcium has "attached" itself to the side of a spa, sometimes light acid is scrubbing is the only thing that will remove it so that you can start "clean"...I'm not talking about taking gallons of acid and dumping it all over the spa, I meant just mixing up a small pail of diluted acid and lightly scrubbing areas that it has attached to, does not effect the surface one bit.  This process is only if you've let it go too long, obviously maintaining your water balance on a regular basis is key

[Chas]

I still would never recommend that to a customer. A professional with breathing apparatus, a pump running the wash water out of the spa as fast as you pour - maybe. But even if you are trying to acid wash just spots, you are still telling a homeowner (no offense) to handle dangerous chems. Pool acid is actually Hydrochloric Acid, cut with about 50% water. Still strong stuff, still not something you should be handling, especially in the relatively closed environment of a tub.

Adding "Spa Down" will do the same exact thing, only it will take several days to accomplish. And, it gets into the plumbing.

Win win.

 

[Leslie]

Thought I'd give you a follow up. Filled tub yesterday morning. At first the ph was 7.9 and the TA 250.
Now after adding the dry acid I have a TA of 180, but the ph is still 7.9. I just added 2 more oz of dry acid and will wait till morning to check it again.

But, here's the good news, no calcium on walls yet!

Thanks for your help!

[TwinCitiesHotSpring]

Thought I'd give you a follow up. Filled tub yesterday morning. At first the ph was 7.9 and the TA 250.
Now after adding the dry acid I have a TA of 180, but the ph is still 7.9. I just added 2 more oz of dry acid and will wait till morning to check it again.

But, here's the good news, no calcium on walls yet!

Thanks for your help!

shoot for a TA of around 100ppm, that combined with a calcium of around 150ppm seems to be a pretty good "sweet spot" imo