Desperately seeking calcium deposit help

[leswa]

Hoping someone here 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 solved the problem
either.

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

Leslie

 

[chem geek]

Welcome to TFP!

The crystals might be calcium carbonate scaling or might be calcium sulfate crystals. Where do you live? I can look up a water quality report for your fill water (or if you use well water, tell us that). You should also consider investing in a good test kit such as the TFTestkits TF-100 or the Taylor K-2006, either of which will accurately test your Calcium Hardness (CH) level as well as other important levels including pH and Total Alkalinity (TA) and of course chlorine. This document shows various types of calcium scale -- calcium carbonate and calcium sulfate.

When they dissolve with vinegar, do they bubble when they do (if they are above the waterline)? It could just be that you aren't managing the pH of your spa and when it gets too high then calcium carbonate forms. You could probably also Lower Total Alkalinity, but first you need that good test kit so order that right away.

 

[leswa]

I took a sample of the water that I fill the tub with to a local pool place and had the calcium level tested. It is 180 which I am guessing is normal, good for a tub. So would I be correct in thinking the calcium is in the plumbing?

On my more recent attempts to get rid of the calcium, I just fill the tub, calcium comes back on walls in 24 hours with absolutely no chemicals added.

I am wondering how to get the calcium deposits out of plumbing. Any thoughts?

(background info: about a year ago the spa was so foamy, and I thought calcium would help. I added a BUNCH) Is it possible this
is where it all came from, that I added so much that I can't get it out of the pipes inspite of many fill and drains since then? It's been since this that I have had the problem, and we havent even been able to use since.

 

[chem geek]

You really need your own good test kit. I would not trust pool/spa store results. We've seen too many times when they are off. Also, your TA level may be high. Did they test TA and pH as well?

Even if you had scaling in the pipes, you might find flakes coming off, but not new scale forming inside your spa unless your pH, TA, CH were in combination too high. Perhaps on your next refill you should use Spa System Flush and do a full decontamination just to get things to a good baseline. Then with your good TF-100 or K-2006 test kit you can accurately know your CH and properly adjust your TA and pH to minimize the chance of scaling while still preventing foaming.