Water movement in a saltwater tank is crucial for its overall health. Not only is the amount of flow important, but the flow pattern is as well.
There are many things to consider when deciding on water flow in your tank. Depending on the types of corals and fish you have in the tank, you can plan out the right amount of flow for them.
Other important reasons for water flow include:
- Gas exchange
- Supplies food to corals
- Directing waste to the filtration
- Maintaining biological balance
This article will cover the best flow patterns for your reef tank.
What are the best flow patterns for reef tanks?
Pulse speed and frequency
Being able to adjust the speed and frequency of your wavemaker or powerhead is important as you are attempting to simulate the ocean’s water current found on coral reefs. This will create a healthy environment for your fish and corals. This makes a huge difference over a constant speed powerhead.
Here are some of the different flow patterns:
Laminar / constant flow
The constant flow mode is not the preferred mode to use but many powerheads don’t have a controllable option. It’s either on or off. The flow rate can’t be changed. With this mode, you can’t make adjustments for different coral types and you could end up with dead zones in the tank where it doesn’t receive any flow at all.
This will cause a build-up of nutrients and result in poor water quality. This mode would be good if you are just trying to add additional flow to the tank. Avoid the laminar flow mode if you have other options available.
Gyre flow or oscillating flow is the preferred flow method. This “wave mode” creates waves at different intervals that pulse out from the wavemaker or powerhead in a back and forth method. This is great for a variety of corals where you can create a very natural swaying movement. It is also great for providing food to the corals.
If you have corals with long sweeper tentacles, this flow mode will help to prevent them from stinging others that are close by. Adjusting the time interval between the pulsing will allow you to create more or fewer waves. Adjusting the strength will create smaller or larger waves.
Turbulent flow mode is a mix of random flow patterns. This will create turbulent water with no dead zones in the tank. This mode is great for SPS corals and some more sensitive corals as the turbulent flow is better for waste removal and keeping the tank clean.
Ecotech Vortech modes:
The Vortech MP wavemakers are one of the best on the market and have been a staple in the hobby for many years. They are designed to create many different water flow patterns and speeds for use with any corals or fish you have.
They are fully controllable and known for their awesome flow patterns like these:
Reef crest random
This is the turbulent flow mode that simulates a random change in speed and intensity to create crashing waves. It simulates a high energy reef environment and is great for SPS corals.
Short pulse consists of high and low flow levels at different intervals. This is controllable between 0.2 and 2 seconds.
This mode is opposite to the reef crest mode as it simulates a low energy reef environment. The pump speed changes slowly to create the gentle currents of a lagoon.
The Vortech gyre mode will produce flow patterns of clockwise and counterclockwise flow levels. The water will pulse back and forth between time of 2 seconds and 2 hours.
Check out the Vortech pump flow calculator here.
How to choose the best flow pattern?
Choosing the best flow pattern for your tank is important for its overall long term health. Depending on the livestock in your tank and its specific flow needs, you should plan flow patterns accordingly. It might take some adjusting and you will need to adjust as you add or remove corals.
With proper planning and observing your corals, you will find what works well for your tank.
Take this into consideration:
LPS vs SPS vs Soft corals
SPS corals will generally require more flow and varied patterns where LPS and soft corals do not need as much.
Certain fish do not like much water movement and a strong flow with turbulent patterns can be harmful to them. The Copperband butterfly is an example. Other fish like the Clown tang prefers a stronger flow and can handle it much easier.
The type of substrate you use in the tank will affect the amount of flow you decide to have. Very fine sand can get blown around the tank very easily and having high water flow can make a mess and harm your corals. Some people prefer to have a bare bottom tank when they require higher flow rates or SPS coral tanks.
How much flow should you have in a reef tank?
Turnover rate is a term normally used with reef tanks and water movement. This is a number given to the number of times your main tank water volume will cycle or turn over. A normal turnover rate is around 20-30x for the water volume in your tank.
For example, if you have a 100-gallon reef tank with LPS corals, you will want a wavemaker capable of producing 2000-3000 GPH. If you have SPS corals, you might want a larger turnover rate.
Can you have too much flow in a reef tank?
Yes, you can have too much flow in your tank. It doesn’t matter if you have a fish only tank or a full reef tank, it’s possible to have too much flow. Every tank will be different.
Where should I place my aquarium wavemakers in the tank?
Proper placement of your wavemakers is important as you will have better control of flow and directional patterns in the tank. You can place them on the rear or side panels at various heights based on the tank’s needs. Also placing your wavemakers in a strategic position will help with the overall biological balance of the tank.
Determining the best flow pattern for your tank will depend on the many factors mentioned in this article. Each flow pattern has a unique purpose and some are better than others depending on the livestock in your tank. Plan ahead of time so you have the right wavemaker or powerhead based on your stocking plan for the short and long term.