The filter of your reef tank works best when you maintain a proper water flow rate. To get a clean aquarium for an extended period and ensure a healthy environment for the tank creatures, maintaining a definite Gallon Per Hour (GPH) flow is an excellent and effective approach.
If your reef tank is dominated by softies and LPS corals, you can start with 10X GPH of your tank capacity. However, if SPS corals or mixed corals dominate your reef tank, you should maintain at least 30X flow rate of your tank water volume.
Are you wondering why the GPH is 10X the volume of the tank? To be frank, a reef tank is supposed to get faster flow rates consistently to keep the corals and other inhabitants healthy.
In this article, I am going to talk about the factors that affect the flow rate and how to choose the proper flow rate for your reef tank. Let’s go ahead.
What is GPH? (Understanding Flow rate)
You might already know that GPH stands to mean Gallon Per Hour. Usually, it indicates the flow rate of the filters. It gives us an idea about the maximum gallons of water that flows to a tank through filters in an hour.
GPH rate varies due to the difference in filter type, filter strength, filter state, and efficiency.
The entire volume of aquarium water usually runs several times in an hour through the filter. Though many aquarists think that the higher the GPH, the better it is for the tank, you should not go beyond the limit as too much flow can create uncontrolled water movement.
When there is too much water movement due to excessive GPH, some fishes might find it difficult to swim or rest which will stress them.
Though many people mistake using the phrase “turnover rate” to indicate GPH, the phrase has a different meaning. The turnover rate just shows how efficient a filter is.
What Affects Flow Rate in Your Reef Tank?
Calculating the exact water flow rate might seem different. Certain factors might affect the flow rate negatively. Let’s check some of those:
The flow rate shown on the pumps indicates the flow rate under 0’ degree head height or optimal conditions. However, conditions may not be perfect always.
You can understand this if you look at the water level of your aquarium. Usually, most of the aquarists keep the water levels about four feet off the floor.
Wet or dry filters, canister filters, and modules require the water to be pushed upward. In that scenario, even if the flow of your pump is high but the water pressure is low, the water flow rate drops significantly in water tanks where the water level is four feet off the ground.
The flow rate also drops by elbows or sharp turns in the tubing. If you’ve got a smaller tubing compared to the pump’s requirement the flow rate also slows down.
Do not let the filters get dirty or clogged. Dirty or clogged filters are responsible for slowing down the flow rate.
The flow rate also drops by elbows or sharp turns in the tubing. If you’ve got a smaller tubing compared to the pump’s requirement the flow rate also slows down.
Do not let the filters get dirty or clogged. Dirty or clogged filters are responsible for slowing down the flow rate.
How Many GPH for 30 Gallon Reef Tank?
Many men, many minds. Reef aquarists are not in any agreement to say that all reef tanks need a certain number of GPH.
How many GPH you need for your 30 Gallon Reef Tank varies greatly on the type of corals you have.
If your reef tank is dominated by softies and LPS corals, you can start with 300 GPH. However, on the other hand, if SPS corals or mixed corals dominate your reef tank, you should maintain at least 900 GPH.
All the reef tanks are unique and that’s why the aquarists have different opinions about the exact GPH.
My suggestion would be to start with the minimum (as I recommended) and then increase the GPH if your reef tank demands so.
Why Does a Reef Tank Need Higher Flow Rates than Freshwater Tanks?
While 120 GPH is enough for a 30 gallon freshwater tank, that might be insufficient for a reef tank of the same volume. Note that reef tanks require more GPH than freshwater tanks to let the water move through all the areas of the aquarium.
I have just mentioned that a 30 gallon reef tank requires approximately 300 GPH of water flow. However, some aquarists suggest that reef tanks with SPS might need a higher flow rate of up to 50X, and reef tanks with non-SPS might require up to 30X of flow rate.
If your reef tank contains large fishes, you should consider increasing the GPH. You can also think about adding extra powerheads so that all the fish detritus can be filtered out and removed.
Things to Consider for Maintaining a Steady Flow Rate in Your Reef Tank
There are certain things that you should not ignore if you want to maintain a steady flow rate on your reef tank. Let me tell you some of those:
- No matter how much water flow gets into the tank, make sure that the invertebrates don’t get them directly upon them. Place the invertebrates in a place where the water will not strike heavily on them.
- Make sure that the hiding spots are away from the direct currents. Use submersible devices that are reef-safe.
- Consider buying two small pumps than one large pump. Two small pumps can serve you better than one big pump.
- Do not forget to clean the pumps and filters after every 6 months of use. On top of that, changing the media filter as required is also essential.
- It is great to check your reef tank daily to see if everything is going well. In case you notice stress or stalled growth, you need to adjust the water flow either by increasing or decreasing that.
- If you see that the fishes are having trouble moving or swimming in heavy flow, you should consider lowering the GPH.
How to Choose Proper Flow Rate for Your Reef Tank?
Determine the GPH Water Flow: Determining the GPH water flow rate is a prerequisite for maintaining proper water flow. When you buy a new pump, you should check the flow rate given by the manufacturer and then divide that with the tank water volume. The result is the GPH you are going to have.
Consider the Type of Corals: The best way to choose the right water flow for your reef tank is to consider the types of corals you intend to keep in your tank. If you just keep softies and LPS corals, a 10x turnover rate will be pretty good to start with for your tank. On the contrary, if your tank is dominated by SPS corals, you might need a 30X turnover rate or more.
Aspire for More: Most of the aquarists suggest maintaining more water flow than less. I have suggested you using 10X for soft corals and up to 30X for SPS corals. But, note that this is not a universal opinion. Many aquarists even suggest using 50X or more for SPS and mixed coral reef tanks. If you think that your tank needs more water flow, feel free to try that.
Add Powerheads and/or wavemakers: To let the water flow throughout the tank, adding powerheads and wavemakers is really helpful. Powerheads help to create a turbulent and indirect flow that’s effective for healthy coral growth.
Final Thoughts
By now you know exactly how many GPH you need for a 30 gallon reef tank. You’ve also learned about the factors you should consider for the appropriate water flow rate in your tank.
No matter how big or small your tank is you should strive to maintain the right water flow for the healthy growth of fishes, corals, and invertebrates. Choosing the right GPH for your tank will help those creatures to thrive and maintain a proper marine environment.
