How to lower pH in pond water

Art Wolfe/Photodisc/Getty Images

Regularly check the pH levels in your pond (at least once every 2 to 3 days), especially if you have fish or other organisms living in and around your pond. A pH level that is too low will make the water too acidic; a high pH level will become too alkaline.

The pH level on your pond will fluctuate regularly, and will typically be higher in the afternoon than in the morning. Test at a regular point in the day; the ideal time to test is midday.

Test your pond water's pH level. The level should read between 6.5 and 7.5. A measurement too high will often indicate "hard" water, or water that has too much calcium and/or magnesium and measures about 7.8 on a test kit. In addition, a level too low will be too acidic; plants and fish can become very sick. Low levels measure below 6.3 on a test kit.

Purchase Pond Up, Pond Down and Pond Stabilizer solution from your local hardware supplier or garden centre. Keep all three solutions on hand, using certain ones depending on your pond's needs on any given day. Add 1 tsp per 190 litres (50 gallons) of water in your pond. These solutions are all natural and will not harm your plants or animals. The Pond Buffer Stabilizer will only be used as needed, and you will use 60 ml (1/4) cup per 760 litres (200 gallons). The Pond Buffer Stabilizer will be used in your pond water after you have lowered the pH level in the pond. After the pond water reaches an optimal pH level, you will use the Buffer Stabilizer for the next 2 to 3 days to make sure the pH level remains balanced. After 2 to 3 days, the pond water should remain stabilised without the Buffer Stabilizer solution.

Purchase a small bag of peat moss. You can apply the peat moss at any time in your pond, but this will become especially important if you continue to have high pH levels in your pond. Peat moss will help stabilise pond water, but should be used sparingly as to not interfere with other plant or animal life.

Place your peat moss near your waterfall, or by your pond filtration system. This will help filter out harmful bacteria which can raise pH levels. Place about 15 cm (6 inches) of peat moss in this area and let it grow. The peat moss will absorb excess calcium and magnesium in the water.

Allow the peat moss to grow no more than 30 to 35 cm (12 to 14 inches) total. Allowing it to grow larger can start to interfere with other life forms; the peat moss can start to use up nutrients needed for other life.