CYCO Grow XL 0-40-0 | Concentrated Phosphorus Additive Australia

CYCO Grow XL

CYCO Grow XL is a Platinum Series additive built on super phosphoric acid, giving it a registered analysis of 0-40-0. Phosphorus is the element behind energy transfer and root formation, and Grow XL delivers it at a concentration nothing else in the range comes close to. It's used from week 3 of vegetative growth, once a plant has enough root mass to make use of it.

What 0-40-0 Actually Means for You

Forty percent phosphate is a lot. For comparison, Swell is 5% and Potash Plus is 4%. Grow XL is eight to ten times the concentration, which is why it comes in 100mL, 250mL and 500mL bottles rather than the litres everything else ships in.

Two things follow from that, and both matter more than any benefit claim.

It will move your pH. Super phosphoric acid is exactly what the name says. Adding it drops pH, sometimes sharply. Add Grow XL to the reservoir before you make your pH adjustment, then correct once. Adding it after you've dialled pH in means doing the job twice.

It's easy to overshoot. Excess phosphorus competes with iron and zinc for uptake, so overdoing it produces symptoms that look exactly like a micronutrient deficiency. If you add Grow XL and new growth starts coming through pale, back off rather than reaching for an iron product. Our nutrient lockout guide covers how to tell the two apart.

CYCO's own claim is that Grow XL supports the uptake of iron, nitrogen and potassium. That's their wording and we can't verify it independently, and it sits awkwardly against the phosphorus and iron interaction above. What the analysis unambiguously supports is that this is a concentrated phosphorus source for root development.

Key Benefits

• Concentrated Phosphorus: 40% available phosphate for root formation and energy transfer through early growth.
• Small Doses Go Far: A 100mL bottle covers a full cycle for most home setups, which is why the sizes are small.
• Root Development: Aimed at building root mass from week 3, before the plant hits the demanding stages later on.
• Runs in Any Medium: Suitable for hydroponics, coco and soil, with a lower starting rate in soil.

How and When to Use

Start from week 3 of vegetative growth. Earlier than that and the plant lacks the root mass to use it, and you're adding a strong acid to a seedling that doesn't need it.

Add it to your reservoir before adjusting pH, then correct once and check EC. Expect the reading to climb. If you're already running a base nutrient with meaningful phosphorus, factor Grow XL in rather than adding it on top and hoping.

Don't run it alongside a bloom booster. Both are phosphorus-led and stacking them is the fastest way to lock out iron and zinc.

Technical Specifications

• Format: Liquid additive
• Registered Analysis: Available Phosphate (P2O5) 40%. Nitrogen 0%, Potash 0%.
• Derived From: Super phosphoric acid
• Effect on pH: Lowers it, often noticeably. Dose before adjusting.
• Best Used: From week 3 of vegetative growth
• Do Not Combine With: Bloom boosters or other high-phosphorus additives in the same feed
• Compatible Media: Hydroponics, coco coir, and soil

Available Sizes

• 100mL
• 250mL
• 500mL

CYCO Grow XL is a pharmaceutical grade, Australian made phosphorus concentrate for root development from week 3 onward.

Frequently Asked Questions

What is the NPK of CYCO Grow XL?

0-40-0, derived from super phosphoric acid. No nitrogen, no potassium, 40% available phosphate. It's a single-element product and by a wide margin the most concentrated thing in the CYCO range.

Why does my pH drop when I add Grow XL?

Because it's an acid. Super phosphoric acid is the source of the phosphorus, so adding it lowers pH the same way a pH Down product would. Add Grow XL first, then adjust pH once, rather than correcting twice.

Why does my EC climb after adding it?

At 40% phosphate even a small dose contributes meaningfully to total dissolved solids. Check EC after mixing and reduce your base nutrient if the combined figure runs above your target for the stage.

Can I use Grow XL with a bloom booster?

No. Both are phosphorus-led products, and running them together pushes phosphorus well past what the plant can use. Excess phosphorus competes with iron and zinc for uptake, which produces what looks like a micronutrient deficiency but is actually overfeeding.

When do I start using CYCO Grow XL?

From week 3 of vegetative growth. Younger plants don't have the root development to use it, and a concentrated acid is the last thing a seedling needs.

Can I use CYCO Grow XL in soil as well as hydroponics?

Yes, at a reduced starting rate. Soil buffers nutrients and holds phosphorus differently to an inert medium, so start low and watch how the plant responds before increasing.

What is the shelf life of CYCO Grow XL?

Unopened, 2 years when stored cool and out of direct sunlight. Once opened, use within 12 months.

Does CYCO Grow XL ship fast within Australia?

Yes, CYCO Grow XL ships from within Australia with fast tracked delivery Australia-wide. Most orders to VIC, NSW, QLD, SA and ACT arrive within 2 to 5 business days. WA, NT, and TAS orders typically arrive within 5 to 12 business days.