Restore balance — fix high pH fast. Use this formula for better nutrient absorption and healthier growth.
Precisely lowers pH to ideal levels (5.5–6.5)
Works in soil, coco, hydroponic systems, DWC, aquaponics, and more
Highly-concentrated, dye-free, and additive-free
Clean formula made with phosphoric acid
Trusted by home gardeners and pros alike
"A little goes a long way. My plants bounced back fast."
$11.99
Better results start with the right pH.
Even perfect feeding fails if your pH drifts into chaos. Humboldts Secret pH Down brings equilibrium back, ensuring your plants absorb the nutrients they need — quickly, accurately, and without junk. All it takes is a few potent drops, and your plants can flourish.
Test your water or nutrient solution with a digital pH meter
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If pH is above 6.5, add pH Down one drop at a time per gallon
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Stir and re-test until pH is in the 5.5–6.5 range
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Apply to your plants as usual
Gardener’s Tip: Potent formulas demand precision. Go slow, and use a dropper or syringe to unlock best results.
Don’t let high pH stall your grow.
Too much alkalinity means locked-out nutrients, wasted water, and stunted plants. If your leaves are yellowing, curling, or just not thriving — check your pH.
Humboldts Secret pH Down gives you the fast, precise fix for high pH. No mystery dosing. No advanced alchemy. No added stress.
Can I use pH Down in hydroponic or deep water culture systems?
Yes. Our pH Down solution is fully water-soluble and designed for hydroponics, DWC, and aquaponic systems. It dissolves cleanly, won’t clog lines, and allows for precise control. It’s trusted by gardeners managing large-scale water reservoirs and small home systems alike.
Is pH Down safe for edible plants like vegetables and herbs?
Absolutely. Our formula contains only high-purity phosphoric acid and no dyes, fragrances, or harsh additives. It’s safe for leafy greens, tomatoes, herbs, citrus trees, and more. Just dilute carefully and adjust with a pH meter.
How much pH Down should I use per gallon of water?
Start small. Add 1 drop (or 0.25 mL) per gallon, stir, and re-test. This formula is highly concentrated, so it’s easy to overshoot if you eyeball it. Always adjust incrementally using a digital pH meter.
Why is pH balance important for plant growth?
pH affects nutrient availability. Most plants thrive between 5.5 and 6.5. If your solution is too alkaline, nutrients like iron and phosphorus become inaccessible, leading to stunted growth, yellowing, or deficiency symptoms. Correcting pH ensures better nutrient uptake and stronger growth.
Why not use household vinegar or lemon juice as a pH down solution?
Those options are inconsistent and less stable. Household acids lack the strength and precision required for reliable pH control. Humboldts Secret pH Down for soil offers stronger, measurable results with less product and no unwanted TDS spikes.
What happens if I add too much pH Down?
If you overshoot and your pH drops too low (below 5.0), nutrients can become toxic or unavailable. Simply re-adjust using pH Up and re-test until you're back in the ideal range. Always adjust in small increments.
How long does a bottle last?
Thanks to its concentrated formula, even a small bottle can last for months. Many gardeners using it weekly in 5–10 gallon systems report lasting over a full growing season.
Does this work with well water or RO water?
Yes. Whether your water source is high in alkalinity (like well water) or stripped clean (like RO), pH Down is effective at correcting and stabilizing the solution for optimal nutrient absorption.
Humboldts Secret pH Down delivers clean, precise results every time. Trusted by curious beginners to seasoned pros alike, it’s the key to consistent, visible performance — without the guesswork.
