What is correct order of media for canister filter?

[rheemas]

Hi,

I run a 1500L/hr canister filter with three trays. The first tray has ceramic noodles, the second has sinterlated glass and bioballs, and the last has a black coarse sponge. Thereafter the water flows past the UV and back into the tank.

I thought it should be in this order so the bacteria can use the waste in the water before it is taken out by the sponge? What do others do...I would be interested to know.

[DIY]

There is probably 2 schools of thought on this

1) remove as much waste mechanicaly as possible and let bio-filter convert rest to nitrate. This means sponge first to capture the waste and noodles/bio balls after. Downside of this is to work properly you need to replace or clean sponge more frequently

2) allow the waste to break up using coarse media and end up with the finer mechanical filter (sponge) last before returning to tank. Downside of this method I believe is higher nitrates as more waste is trapped / broken down and converted, less is physically removed before needing to be converted.

Reality is both methods work well, for canisters I always have the sponge in the top tray for easier access to change. For some of the canisters I have that works out the sponge is first as the water goes through media trays before getting to the bottom of the canister, and for the other canisters the sponge is last as the water goes to the bottom of the canister first and then up through the media trays...

I prefer canisters that go through the sponge first because replacing/cleaning the sponge captures nearly all the waste, wheras canisters that go from the bottom up through the trays end up with waste sitting in the bottom and require the trays removed and the waste washed of the canister each clean.

[DIY]

Forgot to mention, it's worth checking which way your canister flows.. a lot of the UV canister filters go through the UV first down to the bottom, and then up through the trays. It's easier to build that way as there is less requirement to seal the "UV tube" section between the trays

[rheemas]

Thanks for your input. I have only cleaned my new filter once and wondered why the slime was on the bottom of the sponge in the bottom of the tray. I now know that because of the UV it goes past the light first then up through the trays, so in fact I did have the sponge in first.

I think I might swap the order around to see if a higher flow is maintained for longer periods and I will just have to monitor the nitrate levels to ensure my water changes are still regular enough.

[aquafrogstuff]

rheemas, the way you have ordered the media in the canister (i.e. noodles->glass->sponge) is correct. Notwithstanding the comments above, the noodles are also meant to disperse the inflowing water more equally (aided by their shape) through the filter which is why they should be first.