Random Cory death

[CattyV]

Is this in the Fluval U3 internal filter or do you use a different filter?
[/quote]

Yes, it’s for the U3 filter. Keeps the water super clean either way

Decided the tank can stay with the 15 little fish in for now. Need a break from it. Getting a new carpet instead, for which I’ll need to move the tank out the way of. Might as well whilst minimum fish are inhabiting!

Will see what happens over the course of the next 4-6 weeks whilst sorting that.

[Stephen]

Thanks

I would use the medium sponge and add a fine sponge to each of the outside cartridges (no need for carbon or nitrate/phosphate removers) the fine sponge faces outwards in each cartridge.
You can cut fine sponges from compatible fine filter sponge sheets using the existing medium sponge as a template.
I would also add more Fluval Biomax to the middle cartridge as they do not come with very much biological media.
This will make the filter more efficient.

Just a thought