Many spas and hot tubs can operate effectively with much higher levels. If you have a test kit or test strips that measure for calcium hardness levels in your spa, you can easily check your spa water to see if you have hard (or soft) spa fill water. Most spas and hot tubs will be fine with calcium hardness levels of up to 400 ppm. After that, you may begin to see signs of scaling and cloudy water conditions. Here are some actions  you can take: If it’s just a little above the high end of the range, drain some of the water from your hot tub, add fresh water, and then add a scale control product to keep the calcium level where it should be. You can add scale control weekly, if necessary, but always follow the manufacturer’s instructions for use. If the calcium level is way above 250 ppm, your best bet is to completely drain the hot tub and clean it. When you refill it, use a hose filter to keep at least some of the minerals out of the water. Then use a scale control product to help keep things balanced.