External Filtration.

[lillith112]

I have an external filter on my 170ltr tank, I have 2 questions, I use this tank as a growing on tank for fry but I would like to add shrimp at some point so I have cut up a fish net and cable tied it to the inlet tube to stop fry being sucked up, is there any other way of doing it maybe with a sponge ?.
Second question is how often should the canister medium be cleaned, currently I am cleaning every 2-3 weeks as the tank has a lot of baby fish in it, is that ok or should I be doing it less or more often ?.
Many thanks
Julia

[Fento]

You can use a sponge, or a kind of prefilter. There are a few brand that have their own (for example Eheim prefilters). For my filters water intake I use Haggen sponges, wich have very small holes.
About cleaning the filtering media, it depends on the population of the aquarium and if they generate much waste... if you see in 2-3 weeks it's quite clean (as long as you have your water suitable), you may wait a bit longer... if it's dirty you should clean it often. I couldn't tell you a specific answer for that.