Skip to content

GT Optimum - Growth Technology Hydroponic Nutrient BLOOM A & B

Original price $34.00 - Original price $220.00
Original price
$34.00 - $220.00
Current price $34.00
Original price $34.00 - Original price $220.00
Original price
$34.00 - $220.00
Current price $34.00
Choose a Size
We Support
We Support Red Nose Australia
1% of every sale goes to Red Nose

Free Shipping Image
Free Shipping

When you spend $199*

*Excludes bulky items: soil, tents etc



  • Australia’s most trusted hydroponic twin pack nutrient
  • Formulated by internationally renowned chemist, Carl Barry
  • Available in ‘Grow’ and ‘Bloom’ formulations
  • Unrivalled performance in all hydroponic systems

OPTIMUM – Twin pack hydroponic nutrient.
Want optimum results?  Choose  OPTIMUM – the Original and still the Best!
Optimum is one of Australia’s first and most trusted hydroponic nutrient solutions - an Australian Classic and industry standard!
 This complete and balanced twin pack formulation has been calculated to the highest possible standard of accuracy and is manufactured from the purest and most soluble mineral salts. The inclusion of chelates ensures vital micronutrients remain available to the plant even during pH fluctuations.
Available in 2 distinct formulations, OPTIMUM supplies all the nutritional requirements for healthy plant growth.
OPTIMUM Grow is formulated to supply the needs of the plant during the vegetative stage of its growth cycle. High levels of nitrate-nitrogen encourage rapid leaf and shoot growth, maximizing the young plant’s potential to produce fruit and flowers later in its life.
OPTIMUM Bloom is dedicated to the flowering and fruiting stage of plant growth. The bloom formulation contains reduced levels of nitrogen and enhanced levels of phosphorous and potassium, the elements required for the initiation and development of buds and flowers.
Optimum is suitable for all types of hydroponic cultivation.  It is especially recommended for NFT, Flood and Drain and recirculation systems containing perlite or clay.
Vegetative Optimum Grow 1.5 – 2.0 mS 5.8 – 6.2 Flowering Optimum Bloom 2.0 – 2.5 mS 6.0 – 6.5
 Gradually increase the nutrient strength during each cycle ie, start on 1.5mS during the Vegetative growth stage and gradually increase it to 2.0mS towards the end of the stage,  DO NOT IGNORE pH.  Certain minerals can become inaccessible to the plant when the pH of the solution is outside the recommended range.  If using a pH Test Kit, aim for ‘6’.
 Both Grow and Bloom have an ‘A’ part and a ‘B’ part.  These must be added in equal amounts as per instructions to maintain the ideal nutrient profile for the plant.  Re-circulated nutrient tanks should ideally be changed once a week in order to maintain the optimum mineral nutrient profile in the tank.
 To introduce an organic component to your nutrient solution, use GT FULVIC.  To maximize the flowering potential of your plant during the flowering stage, use GT SUPER.  For a plant with extra strength and vigor, add GT SILICA to your nutrient solution.

Our Customers Love Us!