What to do if your surface feels like sandpaper and/or has calcium buildup?
Cause - Anytime the pH rises too high, even if it is for a short period of time, the calcium in the water will precipitate out and start forming on the surface of the spa. It will start out as a white powder and then turns into hard crystals that feel like sandpaper on the surface. The natural tendency of the pH is to drift up most of the time.
Remedy - The first thing that you need to do is to make sure your pH is in the ideal range of 7.2 to 7.8 ppm. At this point you have two options, drain your tub now or wait until it is time to drain your tub later. Either way, you will need to drain it sooner or later to get rid of the calcium buildup completely. Below are the specific instructions for each option.
1. Drain your tub now- If you are wanting to drain your tub now, we will want to reverse the process that caused the buildup by lowering the pH down to the point where your water is slightly acidic. This will dissolve the buildup on the surface and in the lines and equipment. You will want to add a full bottle of Arctic Pure Adjust Down (2lbs) directly into the water, and yes, we mean the full 2 lbs. Make sure your filtration cycle is running. Open up all the diverter valves, air controls, waterfall valves, jet valves, etc. This helps ensure that the acidic water will reach all the lines where the calcium has built up. You will also want to turn on your pump 2, pump 3, and blowers 3 or 4 times over 24 hours to get the acidic water flowing through those lines as well. Do not use the spa during this time due to the acidic water. After letting the spa circulate normally for 24 hours, you should be able to see that the calcium buildup is gone. Now you can drain and refill the spa normally. Be careful where you drain the water to as it is more acidic than normal since it might cause damage to grass, plants, etc.
2. Drain your tub later- Once your pH is in line (7.2 - 7.8), you can take a non-scratch scrub pad**** and scrub the surface of the spa to get rid of the majority of the buildup while you are using the spa. This will usually make your water a little cloudy but it will clear up as the filtration catches up. Make sure and maintain your pH properly in the coming weeks to prevent the buildup from returning. When you are ready to drain your spa, you will need to follow the instructions above to completely get rid of the buildup in the lines, equipment, etc.
Prevent this from happening again - The key to preventing calcium buildup is to keep your pH within the ideal range of 7.2 to 7.8 ppm. Having hard water is acceptable as long as the pH remains in the okay range. The Arctic Pure test strip bottle says to keep your pH from 7.2 to 7.8 ppm, but since the natural tendency for pH is to rise, we would suggest keeping your pH at the lower end of the acceptable scale at 7.2 ppm. You will probably want to test your pH at least once a week to make sure that it is properly balanced. If you find that you have to add pH decreaser every week, this may mean that you are not adding enough pH decreaser with each dose.