Sandpaper Feel To Tub Lining

[rockspop]

I've got a Dimension One chlorine spa. I recently filled it using my garden hose that bypasses my water softener. Minnesota water is pretty hard and I live in a small town with a real bad hard water problem.

I must not have got my PH perfect, I was adding an ounce of muratic acid every day for a week.

Now I've got some kind of mineral deposit ALL over the inside of my tub. Must be in the pipes too, eh?

Will Spa Flush 2000 get all this out of my pipes and how do I prevent this from happening again, please?

Thanks,

Phil

[quantumchromodynamics]

Scale is caused by an excessively high CSI (Calcite Saturation Index). If you can post a full set of chemicals we can help you figure out what to do to prevent scale.

[rockspop]

I'm sorry, am I understanding you correctly that I should go get a complete water analysis and post all the individual levels?

[quantumchromodynamics]

Here are the chemicals that you need to measure and report:

Free chlorine

Combined chlorine

pH

Total Alkalinity

Calcium

Cyanuric acid

Borate (when used)

Temperature

Also, please measure and report the pH, TA and calcium levels of the fill water.

These are chemicals you need to measure and manage at all times. You can use the Taylor K-2006 test kit to measure all of these chemicals except borate. Borate levels can be measured with test strips to an acceptable level of precision. Borates can help prevent pH spikes. You will probably need to fill the tub using at least some water from the water softener.

[quantumchromodynamics]

The formation of calcium carbonate scale (calcite) CaCO₃ is endothermic. That means that for calcium carbonate scale to form, it has to absorb heat. This is why calcium is more soluble in cold water than in hot water. The heat is stored in the calcium carbonate until it dissolves. When the calcium carbonate dissolves, it releases heat (it's exothermic).

Since your heater element is hot, it will be more scaled than the rest of the tub. The scale will act as an insulator trapping the heat and causing the element to overheat. You should turn off the heater until the scale is redissolved.

You should drain the tub and refill with a mix of softened and unsoftened water so that the calcium level is about 50 to 100 ppm. Leave the heat off until all calcium carbonate scale is dissolved. Lower the TA (Total Alkalinity) to about 50 ppm and the pH to about 7.2. Allow the tub to circulate for a few days until all of the scale is dissolved. Maintain FC at 2.0 to 5.0 with liquid chlorine.

Once all of the scale is dissolved, recheck all levels and maintain your CSI (Calcite Saturation Index) at about -0.3 to -0.1. You can then reheat the water and the scale should not return. You can use the pool calculator to calculate your CSI.

I recommend that you add 50 ppm borates from boric acid to help manage the pH.

I recommend that you read the following:

Nitro's approach to Water Maintenance

Dichlor/bleach Method In A Nutshell

Chlorine Demand

Also, have you used any sort of phosphate based pH buffer?