1. Using a Clear Hydroponic Water Pump Reservoir

This is a common mistake with DIY systems and a mistake I made with my first raft system. Most hydroponic systems require some kind of water storage tank, either static and aerated with an air pump or pumped through the system, where it gets naturally oxygenated.

However, anywhere you find a pool of nutrient-rich water sitting at a pleasant temperature, you risk getting algae to bloom through a process known as eutrophication. A hydroponics users’ worst nightmare!

We want to keep the high nutrient levels in the water because our plants need those nutrients to grow, so the next best course of action is to ensure your water reservoir is as dark as possible. Having the tank dark stops Algae from being able to photosynthesize, stunting its growth. An added benefit of an opaque tank is that it helps moderate temperature well.

But be sure to keep the water tank out of direct sunlight. The simple solution is to paint your reservoir with a few coats of black paint. Some people like to use a mixture of black and white color in layers, but the key is to ensure no light gets to your reservoir and the temperature is as consistent as possible.

2. Ignoring pH Levels

Getting the pH levels in your system spot on ensures that your plants absorb the most nutrients possible, meaning they’ll grow quicker. One of the beauties of hydroponic growing is that you can supercharge the growth of your plants by removing weeds, ensuring they have all the correct nutrients, and giving them more sunlight than they would typically get. This can speed up growth by 25% and increase yield by 30%.

Cast your mind back to high school chemistry for a second; pH is measured on a scale of 0-14, with 0 being very acidic, 7 being neutral, and 14 very alkaline. pH litmus strips allow you to eye the approximate pH based on a color scale – be aware not all testing strips use the same colors!

I’ve found that plants typically like a slightly acidic nutrient solution with a pH between 5.5- 6.5. I always use this as a base point before varying the pH as I tinker and test to find the optimal level, but being in this range will set you up for successful growth. The simplest ways to test pH are via litmus paper, or the more precise method (and my favorite) is using a calibrated pH pen.

3. Not Learning About Hydroponics Nutrients

If you’re researching hydroponics, you’ve probably realized that nutrients are key to ensuring your plants thrive. Many growers don’t recognize that nutrients were not all created equal and that you must carefully monitor the amount of nutrients in your system.

Typically, nutrient mixtures will advertise their NPK ratios. These letters all relate to a significant nutrient: N (Nitrogen), P (Phosphorus), and K (Potassium). If you are still deciding which setup is right for you, you can read about benefits of hydroponic systems to see how different setups handle nutrient delivery.

Here is my handy list to tell if you need to add more of a particular nutrient:

• Leaves are dying or have stunted growth – Lack of CO2
• Leaves are very dark green and still dropping – Lack of phosphates
• Yellow tips to leaves – Lack of potassium
• Dark marks on leaves – Lack of magnesium
• Yellow, wilted leaves – Lack of nitrogen
• New growth is pale/white yellow – Lack of iron

4. Hydroponics Oxygen For Drowning Plants

Plants need to respire (take in oxygen) and photosynthesize. The roots of plants need to breathe. Therefore, we need to ensure the plant roots have a ready supply of oxygen. This is easy to achieve in systems where the water is flowing, such as an NFT build, so ensure the roots aren’t completely submerged.

However, we need to oxygenate the water in static systems such as raft systems as it isn’t moving around manually. Fortunately, this is easy and reasonably cheap to do by using air stones. If you are interested in vertical solutions, you should check out how hydroponic towers work as they offer unique ways to keep roots oxygenated.

5. Getting Lighting Conditions Wrong

Plants need light for photosynthesis. Hydroponics allows us to deliver sunlight even when the sun isn’t shining. The ideal light system for hydroponics offers a good spectrum of light, stays cool, and uses minimal electricity.

The standard lighting options for growers are:

• T5 Fluorescent bulbs: Cheap and long-lasting, but not ideal for flowering.
• High-Intensity Discharge (HIDs): Better usable light range but run hot and have a shorter life.
• LEDs: Efficient, long-lasting, and offer full-spectrum control.

Typically I would recommend T5 lights for beginners on a budget placed around 8” above your plants. If your budget stretches, go for LEDs, which are far more efficient and will make your life much easier.

6. Using Tap Water

Many people don’t realize how much effort goes into making their tap water safe to drink. Water treatment is an intense process; depending on your location, the water may have additives like chlorine that can kill useful bacteria on plant roots. Before you fill your tank, you should read about water quality for hydroponics to understand your best options.

My recommended alternative for beginners is to collect rainwater. Just watch the pH levels, as it varies from region to region. If you still have doubts about your local supply, you can check our common questions for more troubleshooting tips.

7. Not Checking Water Levels Regularly

Most growers will shelter their growing systems inside or in grow tents; therefore, rain can’t top up the levels. As a grower, you need to ensure that your roots have access to water without being completely submerged (unless you have an airstone). Nutraponics systems are often touted as ‘set and forget’ systems, but forgetting to check water levels is a leading cause of plant stress.

8. Not Spotting Root Rot

Root rot is caused by a lack of oxygen. One of the more obvious indicators is a slight ‘musty’ smell. If you notice this, look at your roots; if they’re brown and slimy, you have root rot. This is why maintaining oxygen levels via air stones or flowing water is so critical to your success.

9. Not Understanding Electrical Conductivity (EC)

EC measures the ions in the water—essentially how many “extra things” are in the water that aren’t pure H2O. For us, this indicates the concentration of nutrients. The higher the EC reading, the more nutrients are available for the plants. Checking the EC and topping up nutrients when it drops too low helps you grow plants bigger, faster, and healthier.

Ready to Level Up?

If you are ready to stop guessing and start growing like a pro, you can get the NutraTower Premium for advanced growing. It takes the guesswork out of the setup so you can focus on the harvest!

BONUS GIFT: I’ve been hard at work putting together what I consider to be the ULTIMATE guide for hydroponics. As a thank you for visiting, I want to offer you a copy of the book at a BIG discount, including two cheatsheets for identifying nutrient deficiencies and ideal pH/EC ranges. Don’t miss out!