The internal filter that came with the 8 gallon fluval tank had nice flow but I hated how it would come apart in the tank when touched. Yesterday I replaced it with a Finnex px-360 canister filter. The new filter is extremely quiet, silent actually and works great. I wish it came with cut-off valves for maintenance. The glass top no longer fits because of the filter intake/outflow so I cut a piece of lexan to replace it.
I also started using Flourish Excel in that same tank to help with the algae outbreak. Installed the Cobalt Neo Therm 25 Watt heater finally. It works great and is so incredibly thin. It barely takes up any space at all.