Insufficient filtration

Insufficient filtration
It’s no surprise that algae will show up in a tank with inadequate filtration. As we’ve discussed, the bacteria in your filter converts the ammonia that algae loves into other compounds. If your filter can’t remove the solid waste and hold enough bacteria for the livestock and size of your aquarium, your water is always going to be low quality with excess ammonia and other organics present.
While many types of filters exist, not all are created equal. You want a filter that can:

1. Hold as much filter media as possible including mechanical (sponges) and biological (e.g. ceramic rings)
2. Pump through approximately 8-10 times your total water volume per hour

Canister filters are ideal for many aquariums, as they hold a lot of filter media (allowing for a large colony of beneficial bacteria) and can turn over a significant amount of water. Where canister filters are not appropriate due to size, flow or space restrictions, a hang-on-back (HOB) filter can be ideal as long as the capacity for filter media is reasonable, or a sponge filter is also an excellent choice.
There is no such thing as “too much” filtration. The more water your filter can circulate per hour, the better – as long as your livestock don’t mind the flow!​​

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