What is the proper flow rate for your 30 gallons aquarium?
The best filter for 30 gallon aquarium will come with the flow rated according to how many gallons the aquarium holds. However, the flow rate that come with the filters are not alway work well for all the case. In some aquariums, you may need the flow rate that higher or slower than it is recommeded.
#1 Average flow rate of 30 gallon tank
Generally speaking, I generally recommend that you should turn over your aquarium volume at least four times per hour. This means that if you have a 30 gallons tank, you need a pump and filter with flow rates of around 120 GPH. The filter with 120 GPH can be able to move 4 times the amount of water in your tank a single hour.
#2 The aquariums that need higher flow rates
Any 30 gallons tank with heavily populated aquariums, or those with large predatory fish or fish that generate large amounts of waste should be fitted with oversized or multiple filters. For example, if you keep a multiple gold fish in your tank, they are quite messy as they generate much of waste, you will need something that larger than 120 GLP.
Reef tanks also require higher flow rate so water is moving in all areas of the aquarium. This is essential for filter feeders. Water currents bring corals the food, oxygen, nutrients, and movement necessary to stimulate growth of them.
If you are keeping these kind of aquarium, for best results, purchase a filter that is rated for an aquarium a little larger than the one you own.
#3 The types of aquarium that need slower flow rate
If you are owing a 30 gallons live plant tanks, the slow flow rate of water will help decrease surface agitation and hold more amount of CO2 that live plants need. Most plants cannot tolerate being in the middle of the flow stream.
Other types of aquarium that need slow flow rate is the tank that you keep small fish, baby fish or betta fish tank. Betta prefer to live in the peaceful habitat, too strong water flow can cause much unwanted stress for them to swim in the current all the time. While small and baby fish can be swept away in the high flow rate.