pH Up

pH Up raises the pH of a nutrient solution. It is needed far less often than pH Down – most UK tap water is alkaline to begin with – but there are three situations where you will not get far without it.

When you need it

• RO or heavily filtered water. Reverse osmosis strips the buffering minerals, so the resulting solution is unstable and often drifts low once feed is added.
• Overshooting with pH Down. Concentrated acid moves a reservoir quickly. Everyone overshoots eventually.
• Naturally acidic inputs. Some organic feeds, and rainwater collection, land well below target.

Using it

Most pH Up is potassium hydroxide, which adds a small amount of potassium along with the correction – worth knowing if you are already running a heavy PK booster. Add nutrients to the water first, then adjust, a millilitre at a time with a stir and a pause between doses. Never mix it directly with pH Down or with silica concentrate.

Target ranges

5.5-5.8 for hydroponics and rockwool, 5.8-6.2 for coco, 6.0-6.8 for soil. In organic soil you rarely need to adjust at all – a living soil buffers itself, and chasing pH usually does more harm than leaving it alone.

A meter is essential: see pH and EC management.

Why buy pH Up from The Hydro Bros?

We are a hydroponics shop in Croydon and we can tell you whether your water actually needs it. Discreet UK and European delivery, and excellent customer reviews on Trustpilot.