Calcium Increaser for Hot Tub
Calcium Increaser for Hot Tub
Maintain optimal balance and prevent corrosion for clear, cloud-free spa water.
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Our Calcium Increaser maintains optimal balance, shields against equipment corrosion, and ensures crystal-clear, cloud-free water for a pristine spa experience.

1 level capful (2 level tablespoons) of this product will increase the calcium of a 500 gallon spa by approximately 10 ppm.
DIRECTIONS for use:
- Determine amount of product to be added using a calcium hardness test kit.
- Pour proper amount into spa or hot tub with equipment turned ON.
- Run filter for 1-2 hours.
- Water may be retested in 20 minutes.

How do I decrease calcium levels in my hot tub?
If calcium levels are just a little high, drain some water from your hot tub and replace it with fresh water. Test levels and repeat if necessary. Always use AquaDoc's Stain & Scale control to keep Calcium levels at the proper levels. If Calcium levels are extremely high, it's recommended that you completely drain your hot tub and refill.
What if Calcium scale deposits have formed on my hot tub?
If you're already dealing with a scale issue, we recommend you use AquaDoc's Spa Stain & Scale formula to help remove and prevent future scale buildup. It's also recommended you take special care to balance your calcium levels moving forward to reduce overly hard or soft water.
Where is AquaDoc's Calcium increaser made?
Our product is proudly made, packaged, and shipped from the USA.

The price you see is the price you pay.
We don’t play pricing games.
That’s why all orders over $75 ship free—no tricks, no hidden costs.
Why is AquaDoc the Best in Pool Chemicals?
- 🌿 Paraben free & Aluminum free
- 📦 Fast Shipping
- 🇺🇸 Made in the USA
Order With Confidence
If our products don't solve your (pool or spa-related) headaches, contact us for a 100% refund. Free shipping on all orders over $75!
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100% Paraben Free
Say goodbye to parabens that can potentially be harmful to your family. All of AquaDoc's chemicals are paraben and aluminum free.









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Does the job
A little pricey
Good product, good price
Good product, good price
Exactly what I ordered
Used in a hot tub
Works well in my hot tub
Product works as described. I’ll order again.
Hot tub product
We purchased this to help balance the water in our spa. We use bromine, not chlorine. The product qas easy to use, was reasonably priced and very effective.
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