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 Your one-stop Hydroponic Superstore in Melbourne 


Should I use EC & pH meters?
Trying to run a hydroponics system without meters can be very difficult, and it would be hard to achieve optimum results.
We would always recommend the use of meters for peace of mind.

What EC (PPM) or CF should I maintain?

This can vary according to the growth phase, time of year and type of plant being grown. 

eg: If you’re using RAPID Range Nutrients and you have vigorous, fast growing plants such as a tomato plant, to maintain a

safe nutrient level and minimise salt buid-up then the following will apply:





Early Veg

1.0 EC

1 - 1.4EC




Late Veg through to harvest           

up to 1.8 EC

up to 2.4 EC


What pH should I maintain?
Your pH levels should be kept between 5.8 and 6.3 throughout the whole cycle.
What does pH stand for?

PH, or Potential of Hydrogen, is a measure of the acidity or alkalinity of a solution. Aqueous solutions at 25°C with

a pH less than seven are considered acidic while those with a pH greater than seven are considered basic (alkaline).

A pH meter can be very useful in a variety of situations, from measuring drinking water to pool water, or for many

industrial or commercial applications.

PH is one of the most important factors in nutrient management and can make the difference between a

successful, healthy crop and a wasted season. Maximum nutrient absorption occurs when pH levels

are maintained between 5.5 and 6.5.

What does TDS (EC) mean?
Total Dissolved Solids (TDS) are the total amount of mobile charged ions, including minerals,
salts or metals,dissolved in a given volume of water. It’s expressed in units of mg per unit volume of
water (mg/L), also referred to as parts per million (ppm). TDS is directly related to the purity of the water
and the quality of water purification systems.
It affects everything that consumes, lives in, or uses water, whether organic or inorganic.
What are total dissolved solids?

"Dissolved solids" refer to any minerals, salts, metals, cations or anions dissolved in water.

This includes anything present in the water other than the pure water (H20) molecule and suspended solids.

Suspended solids are any particles/substances that are neither dissolved nor settled in the water,

such as wood pulp.

In general, the total dissolved solids concentration is the sum of the cations (positively charged) and anions 

(negatively charged) ions in the water. Parts per million (ppm) is the weight-to-weight ratio of any ion to water. 

A TDS meter is based on the electrical conductivity (EC) of water. Pure H20 has virtually zero conductivity.

Conductivity is usually about 100 times the total cations or anions expressed as equivalents.

TDS is calculated by converting the EC by a factor of 0.5 to 1.0 times the EC, depending upon the levels.

Typically, the higher the level of EC, the higher the conversion factor to determine the TDS.

What is the best water to use?
The best water to use will have a low salt and contaminant level. The lower the EC/ppm, the greater level of
control one has to the nutrients contained in the tank.
If the water used has a starting EC that is too high, you will be limited as to the amount of nutrient you
can add to the system before reaching the highest recommended EC, resulting in a less than ideal nutrient
solution which may lead to lower overall yieads.
 Generally, if your tap water is good enough fo you to drink, it will be fine to use for your plants.
Most hobby growers will use tap water without having too many issues, but for peace of mind test the water before
adding the nutrients to it.
Keep in mind that pH will directly effect the accuracy of the EC reading, so it's best to ensure the
EC levels are measured with a constant pH level.
Is it necessary to aerate the nutrient solution?
Aerating the nutrient solution is a good idea. It guards against stagnant water and improves plant health.
Does the nutrient solution need to be heated?
Try to maintain your nutrient solution at a temperature of 18°C to 25°C to ensure optimum growth.
If you find the room temperature drops below 17'C then suitable heating should be added. 
Water chillers are also available where ambient temperatures are too high.
Our team will be more than happy to recommend a suitable solution for your needs.
My plants keep dying! Why?
The most common reasons are things such as a lack of or too much water, high temperatures or
inadequate ventilation. Ensure enough water is supplied to the plants and keep room temperature
at a level suited to the plants' natural environment.
Always keep the growroom sufficiently ventilated - install suitable fans to bring fresh air
into and take hot stale air out of the room. Crops can also be affected by root disease, caused by
pathogens such as Pythium. Try applying a nutrient conditioner such as 'Saviour' regularly to your nutrient solution
as a preventative measure in order to minimize the risk of root disease and other fungal and bacterial issues, as
well as invigorate the overall health of the plant.
Why are the tips of my plants burning?
Most commonly, the EC level of your nutrient solution may be too high. Try adding plain water to the system to
dilute the nutrients in the tank back to an acceptable EC level. Pour the water directly into each pot, as this will
also flush out excess salts which may build up at the root base.This should be done regularly
(every 2-4 week periods). Recirculating systems should have the nutrient solution replaced with fresh
solution every 1-2 weeks. Not enough water or positioning your lights too close to your plants may
also be the cause. Incorrect pH levels can lead to nutrient deficiencies which can also cause the
leaf to appear burnt. Chech pH levels regularly.
If unsure, feel free to seek advice from one of our professional team members. 
What causes leaves to turn yellow?
Plants need sufficient aeration to ensure optimal oxygen levels. Ensure you have not supplied too
much water, as this will deplete oxygen available to the roots and may lead to root disease
setting in, while also providing a comfortable environment for pest infestation. 
Adding an aquarium air pump to the tank will help oxygenate the nutrient solution and minimise
these problemAlways maintain correct pH levels, ensure the nutrient solution is cool enough, and there’s not too much
salt in the water (EC levels too high).
It’s all about finding the right balance. If you’re still having problems, try adding a calcium/magnesium additive
 into your nutrient solution  along with a root conditioner to help rectify and prevent any deficiencies.
Why do plants stretch?
Plants stretch when light levels are too low,which can occur when lights are being positioned too high above the
plants or if using old lamps that are past their optimum working life.  
The humidity may be too high. Lack of ventilation is usually the cause of high humidity and
cramming too many plants in a small area will make it worse. Ensure your plants have enough access to light and
are not having to compete in a small space, and always provide adequate ventilation.
What humidity should I maintain?
Humidity is best maintained between 40% to 60% . 
If the humidity is too high or too low you will run the risk of disease and stretching in the plants,
which makes it difficult to achieve optimum growth levels and will usually result in 
unsatisfactory yields produced
How much ventilation is necessary?
Ventilation needs to be enough to maintain optimum room temperature and humidity levels while also
providing  plenty of fresh air.
Generally, it’s better to have too much ventilation rather than too little.  
Try to maintain a temperature inside of no higher than outside.
In winter, vent according to temperature and humidity.
You will usually need less ventilation during this period. 
What capacity fan is necessary?
To calculate fan size needed - As a rule of thumb, air exchange of 70 x per Hour would be sufficient.
Calculate the room Volume  (L x W x H) and multiply this by 70. This will provide the
Cubic Metre per Hour your fan size needs to be.

CMH Fan Size Calculator
All Measurements in METRES



1 x 1 x 2

140 CMH

1.2 x 1.2 x 2.3

230 CMH

1.2 x 2.4 x 2.3

460 CMH

2.4 x 2.4 x 2.3

930 CMH

1.5 x 1.5 x 2.3’

360 CMH

1.5 x 3 x 2.3

725 CMH

3 x 3 x 2.3

1450 CMH

3 x 6 x 2.7

3400 CMH

4 x 4 x 2.7

3000 CMH

What size reservoir should I run?
For ease of control use a minimum of 45L per/m2 for your growing area. Any less than this
will require frequent adjustments.
Is it necessary to prune leaf plants?
There is no real need to prune leaves on plants provided that they aren't being grown too large. Large plants may need some
of the larger lower leaves removed, especially if they go pale green or yellow.
How long should it take for clones to strike roots?
The time taken to strike roots on clones varies according to the time of the year and the health of the clones.
About 5-12 days is normal. Using a powerful root stimulant will help to produce roots quicker, and can also be added
in lesser quantities through the growth cycle to help maintain an optimum level of plant health.
Hydroponic grow room - how to set up a hydroponic grow room for beginners

An indoor hydroponic grow room can be set up just about anywhere, from a spare room to a garage or shed.

There are just a few things that you need to take into consideration when picking out the perfect place for a

hydroponic grow room.

To get an idea of just what your plants will require, picture a sunny spot of an outside garden on a warm summer's day.

Just about any plant will grow well in these conditions, and these are the exact same conditions that we need to

recreate in an indoor hydroponic grow room. There are three major categories that we need to focus on in creating

 a grow room: temperature, humidity and light.

Hydroponic grow room temperatures

Temperature is one of the most important design considerations when setting up a hydroponic grow room.

Most plants do well in a temperature range of 20-28°C. It’s not that difficult to achieve this temperature

range in your grow room, especially when the lights are on. If your temperatures become too high, inlet and

extractor fans pumping the hot air out of the room can help to control the temperature. 


You can set up a thermostat to your fan to automate the whole operation. When the lights are off, you need to

make sure that your temperatures do not become too low. Most of all, you need to avoid huge temperature fluctuations

 between the

day and night cycles because this can result in poorly formed plants. 

Hydroponic grow room humidity

A successful hydroponic grow room will always maintain a healthy humidity level. Excessive humidity for long periods

 can result in the formation of grey mould. Once started, it can quickly spread and affect your entire crop.

Using a device called a hygrometer mounted on the wall inside your hydroponic grow room will allow you to keep an eye on

humidity levels. It is important to keep nutrient reservoirs covered at all times so they don’t contribute to higher

humidity levels. Humidity levels can be easily controlled as with temperature by using inlet

and extractor fans to rid the room of heat or humidity. As a general rule, it is best to keep humidity in your

grow rooms between 40-60%, as this will prevent mould problems and minimize pest infestation.

Hydroponic grow room lights

Lighting is one of the most important factors when designing your grow room. This will not matter as much if you’re

in a greenhouse receiving full sunlight, but if you’re in a cellar or a structure with a normal roof,

you’ll have to provide the light yourself and recreate light that is similar to the sun’s rays.

Artificial lighting is a quick and easy solution. Artificial lighting can be easily controlled, and we stock a wide

range of controllers and timers here at Simply Hydroponics. 

By using artificial lighting, the grower can simulate the long days of summer to improve growth levels.

Start to slowly reduce the time the lights are on to simulate shortening days in order to induce the plants to start flowering.

A well designed hydroponic grow room will produce fantastic results with almost any type of plant that you decide to grow.