Post Filter Filter - Such a thing exist?

I've noticed that my filter isnt filtering everything out and is spraying dirt back out via spray bar. It could almost do with an additional filtration stage before the water actually reaches the spray bar. I doubt such a thing exists but was wondering if anyone had any ideas of something similar?

I've currently angled the spray bar to fire against the side wall of the tank to avoid it spraying the dirt over the plants and rocks.

I've added purigen to the filter trays, hoping to solve the problem to no avail. The filter is a eheim pro 3 1200xl and has the provided materials of ehfimech and substratpro and the usual sponge filters.

Have you tried cleaning your hoses and the spray bar itself. A lot of muck accumulates in them and that could be the culprit (assuming the filter itself is clean).

Yeah, I clean both out each time I clean the filter. I clean the filter out each month and replace the disposable floss section.

I suppose the issue is why isnt the filter actually capturing it? Is it unreasonable to expect to prevent all dirt (however small) from passing back out the water outlet?

You will need fine sponge pad to trap the dirt before it returns back to your tank.
Usually, you need a few layers of filter media from coarse to fine sponge pads.

You can try adding filter wool as the first layer of your filter to trap all the dirt.
If it's still not working, add a few more layers of filter wool or fine sponge pad.
Change the filter wool every 1-2 months or when it started to break down.

Recently, I added the filter wools to my hang on filter and my tank water becomes super clear and clean from dirt.

Another possibility is your flow rate could be too powerful which forced the dirt to go through all the layers of filters.

What do you use for your filter medias?
Or it could be that your sponge pads of filter wool/floss isn't big enough to cover the filter and the dirt flows through the sides of the sponge pads.

You can reduce your flow rate or add more filter wools or fine sponge pads.

Thanks, I'll give that a go. I always have my filter at 100% due to the additional purigen that I've added to ensure a high flow rate. The tank is quite large at 550L and even at 100% there isnt always a current at the far end of the tank.

This is the filter layout. I have ehfimech and substratpro in the three material baskets but I could try adding another layer of wool to each to see if that helps. There is already one layer in the top basket shown above.

Wow, powerful filter.

Alternatively, I think you can use a canister pre-filter. It can trap most of the dirt before the water going into the main filter.


And for your big tank, I guess you need at least two filters to effectively filter the whole tank.

The tank (Incipria 530) has a two pre-cut filter inlet points at the bottom of the tank like the picture below so I'm not sure the prefilter would fit. I'd have to find a way of fitting the
prefilter to the tank inlets. They're only £10 though so I've bought one to try.

Also, check the hose size that they can match.
If they cannot match, then you have to use hose adapter. See attached files.