General Hydroponics pH Down Liquid | Phosphoric Acid Adjuster, Qt or Gal

General Hydroponics pH Down Liquid for Dialling In Nutrient Solutions

This is a concentrated liquid acid used to lower the pH of a nutrient solution after the fertilizer is mixed. The working ingredients are food-grade phosphoric acid at 10–25% and citric acid at 5–10%, with the balance water. Straight from the bottle it sits around pH 1.2, which is why tiny amounts move a reservoir quickly. Most crops take up nutrients best between 5.5 and 6.5, and that is the window this acid is meant to reach. Tap water and alkaline wells often push freshly mixed feed above that range. Inert media like rockwool and fast-growing plants can also drag pH upward between reservoir changes. Pulling it back down keeps iron, manganese, phosphorus and other nutrients available instead of locked away. General Hydroponics notes that its own base nutrients are pH buffered, so the bottle often comes out for problem water rather than every mix. Phosphoric acid adds a trace of phosphorus as it works. Heavy, repeated dosing therefore nudges phosphorus up slightly in the tank.

Using pH Down for Plants Without Overshooting

Always add the base nutrients to fresh water first, then adjust pH as the last step. Start with a very small dose, stir thoroughly, and test with a calibrated meter or indicator. Repeat in small doses until the reading lands where you want it. The dose varies with water hardness and feed strength, so a fixed number on a chart would mislead more than help. Large reservoirs reward patience, because acid poured in a rush overshoots and then needs pH Up to recover. Never add it to undiluted nutrient concentrates, and keep it away from alkaline products on the shelf. The acid is corrosive and carries a Danger signal word, so wear eye protection and gloves when pouring. Store it upright, capped, cool and out of reach of children. Unopened bottles keep their strength for about two years. Once opened, plan to finish the bottle within a growing season. The 1 quart bottle suits tents and home reservoirs, while the 1 gallon jug fits rooms mixing several tanks a week.

Key Features

• Phosphoric and Citric Acid: Food-grade acids lower pH quickly and add a trace of phosphorus as they work.
• Highly Concentrated: General Hydroponics says to use it sparingly, so one bottle covers many reservoir mixes.
• Hydro, Coco and Soil: It adjusts recirculating reservoirs, drain-to-waste feeds and watering-can mixes alike.
• Targets the 5.5 to 6.5 Window: Holding feed in this range keeps micronutrients and phosphorus available to roots.
• Two Working Sizes: A quart bottle for small gardens and a gallon jug for rooms mixing larger tanks.
• Long Shelf Life: Unopened bottles keep full strength for about two years when stored cool and upright.

Technical Specifications