What Is A Hydroponic Reservoir? Flood And Drain How To

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What is a hydroponic reservoir and how do you keep a hydroponic reservoir clean? These are important questions that need to be answered especially for newer growers.

If you want to grow your vegetables with hydroponics you will need a hydroponic reservoir and know how to maintain it.

What Is A Hydroponic Reservoir? Hydroponic Reservoir For Flood And Drain System

So What Is A Hydroponic Reservoir Anyway?

A hydroponic reservoir is any tank that holds nutrients and feeds them to plants. Often this is done with a pump. Reservoirs recirculate nutrient solutions.

Some reservoirs are remotely located but some are part of a growing system. The AeroGarden is an example of this. Remote systems would be flood and drain, RDWC, or most dripper systems.

Flood And Drain AKA Ebb And Flow Systems

The flood and drain system is one of the easiest hydroponic systems to set up. Water is held in a hydroponic reservoir and is flooded into a tray by a pump on a timer. An overflow fitting controls the flood height.

Once the pump shuts off any remaining water flows back through the fill fitting and back down into the pump and the reservoir. It produces great results and it is automated.

If you are just getting started growing hydroponic vegetables this is a great way to start. This type of setup can easily be adapted to a drip system by adding a manifold and drip lines.

Part of the beauty of an ebb and flow system is its versatility. You can use it with hydroton, soil, or coco. If you are a hydro beginner I recommend giving flood and drain a try with coco. Growing Vegetables In Coco Coir Get Amazing Results (indoorvegetablegrower.com)

Do you need a reservoir for hydroponics?

Yes, you will need a reservoir for any hydroponic system.

How do you make a hydroponic reservoir?

You can use just about any leak proof container to make a hydroponic reservoir. Plastic totes can make a great reservoir with a lid. You do want a top for your reservoir to keep light and dirt out

How big should a hydroponic reservoir be?

Your reservoir needs to hold enough water and nutrients for your system to run properly. You don’t want your reservoir to drain completely each time you flood your tray.

As an example, I run a 2 foot by 4 foot flood tray with a 27 gallon tote. I can flood it without draining my reservoir. If it were to drain fully your pump might not keep its prime and it is bad for a submersible pump to be run dry.

How does a hydroponic tank work?

Your pump is plugged into a timer that is set to turn on several hours apart and run several minutes before it shuts off again.

The water is pumped up to a flood fitting that fills the tray to a level that you set with the drain fitting. Generally, you want the water to be about half the height of your pots.

It has several sections that allow you to set the water level until it drains back down into your hydroponic reservoir. Any remaining water will drain back into the reservoir through the pump once it is off.

Hydroponic Reservoir Setup

You need to set your reservoir up properly. You will need a pump to pump the solution up to the tray. The pump will be plugged into a timer.

Most timers are made to run on 15 minute intervals but I recommend getting a digital timer that allows you to set the run time in minutes. At least in my systems, 15 minutes is way too long to flood. I generally water 5 minutes or less every 3 to 4 hours apart.

However, it depends a lot on your pot size and how big your plants are. Seedlings may only need one watering at first.

You are going to keep the water circulating so the nutrient solution does not settle. You can use a 2nd very small pump to recirculate the water. Some people use airstones to do this. It is not uncommon to do both.

How do you keep a hydroponic reservoir clean?

It is important to keep your hydroponic reservoir clean. This starts with having a lid for it. It will keep dirt from falling in as well as airborne bacteria and yeasts.

It will also keep light out. If your reservoir has light in it algae will start to grow and you don’t want this.

How do you keep a hydroponic sterile?

There are 2 schools of thought on this. Some hydroponic growers choose to keep their reservoir sterile with chlorine or hydrogen peroxide.

Many other growers prefer a more natural approach and believe in adding beneficial bacteria to their reservoir. This will make it hard for any bad bacteria to start growing.

What is the best temperature for a hydroponic reservoir

I fall somewhere in the middle. I don’t use either unless there is a problem in my reservoir. I also don’t use organics like molasses because they offer a food source for bacteria both good and bad. Generally, if you keep your reservoir temperatures on the cool side you wont have any problems.

The sweet spot for reservoir temperature is 68°. At this temperature, the roots are not cold and water can hold more oxygen. Once temperatures reach 72 degrees you can have problems with bacterial growth.

Should I aerate my hydroponic reservoir?

You certainly can. Most people do and it can benefit your plants. That said it is not necessary. I prefer to use a small recirculation pump pointed to the surface of my reservoir to recirculate my nutrients and add oxygen.

It is not necessary to make bubbles to get oxygenation. By creating surface agitation with a small pump pointed upwards oxygen gets folded into the water. By letting the drain drop into the reservoir you get a waterfall effect which also improves oxygenation. 

Pythium Root Rot

Pythium root rot is the bane of all hydroponic systems. I hope you never get this! Pythium is a water mold that attacks roots and it can kill your plants if not controlled. It covers them in slime and eats them away. It also smells really bad kind of like a really funky gym locker.

It can be a big problem in DWC and RDWC systems. Fortunately, it is much less of a problem in flood and drain systems. Coco is also fairly resistant to it.

How do you sterilize a hydroponic system?

Using chlorine in hydroponics is standard practice for most DWC (deep water culture) systems. There are additives like Clear Rez and UC Roots but they are basically pool shock which is about 65% calcium hypochlorite.

You can make your own solution by adding 28 grams of it to a gallon of water. This is a stock solution that you will add to your hydroponic reservoir at 1 ml per gallon.

You would add it every 2 or 3 days. Personally, I only use this in summer when temperatures inside my reservoir get above 70 degrees.

Hydroponic Reservoir Final Thoughts

I want to encourage you to grow hydroponic vegetables. You will get faster and bigger harvests than growing in a pot of soil. The flood and drain system is easy to set up and use. Learn about using a grow tent for vegetables

You can learn more about hydroponics here: https://en.wikipedia.org/wiki/Hydroponics