Castle Hot Tubs

Blue Horizons 5kg pH Plus



5kg Blue Horizons pH Plus / pH + is a granular balancer used to increase or raise the pH of your hot tub, spa or swimming pool.pH is a measure of how acidic or how basic water is. The pH range goes from 0 to 14, with 7 being neutral. A pH of less than 7 indicates acidity, a pH of greater than 7 indicates a base. The pH of water is a very important measurement of the water quality of your hot tub.A high pH level in a pool or hot tub water can cause limescale build up, which can damage working parts including pumps, heaters and seals.

Why use a pH Increaser?
Use pH plus for raising the pH level in your hot tub, spa or swimming pool water. Low pH levels in hot tub, spa or swimming pool water can cause staining and corrosion. In addition to this, it can cause damage working parts including pumps, heaters and seals. A low pH level may also lead to foaming and damage to plastic parts. In order to prevent this issue, use pH Plus.Test the water using pH test strips, if your pH is below 7.2, use pH Plus to bring the pH to between 7.2 and 7.6 on your test kit/strips.

Application Instructions
1. Pre-dissolve the product in a clean plastic container at a maximum rate of 100g of product per 2.2 gallons (10ls) of clean warm water. Stir well to ensure product is fully dissolved. Carefully add the resulting solution to the pool whilst the pump(s) are turned 'on', preferably near to the water inlets to aid distribution.

2. After a minimum of 8 hours, recheck the pH level and repeat the treatment until the ideal pH is established. In order to achieve the correct level a number of treatments may be required.

Confused about your hot tub water chemistry?

Read our how-to guide on balancing your hot tub / spa / swimming pool water pH levels.

Take a look at our Frequently Asked Questions!

If you require delivery to the Scottish Highlands & Islands, Isle of Man, Scilly Isles, Channel Islands, Northern Ireland or outside of the UK mainland please contact us for a postal quote before making your purchase. Thank you.

Product Specifications

  • Blue Horizons pH plus granules enables you to increase your pools pH to the ideal pool pH level
  • Test the pH of your pool water if it is below 7.2, use pH Plus

You may be interested in:



All good thanks. Used Blue Horizon before. Good product

Richard T

PH purchase fir hot tub


Good products

Robert A

Value for money


Michael M