Two Filters In The Tank?

I've got a vague recollection of somebody (Sue?) answering a member's query regarding having a second filter in the tank. I might be wrong, could have been another site.

Anyway,  This Fluvel 4 Plus looks to be VERY old. It's currently working but I have no confidence in it so have put my tank home made quarantine  filter in as well.
This little filter did seed my quarantine tank in a very short space of time so I know it was active.
I'm killing two birds as I am also using it as an airstone, which is what it is based on (Well seeded Filter sponges/fine floss in a plastic jar. All serviced by an airstone and tubing).

Belt and braces to give me confidence that something will help if the filter fails whilst I'm away.
I do intend to replace it but first I want to replace the light which is pretty grim and buzzes like mad, so I have taken the smaller one from the Nano22 and I'm using that.

Is it likely to help or not?

Thanks for the confirmation Sue.

I definitely will have to wait till this one packs up.
Not been a good day.
We are trying to revamp part of the garden and first the other half half fell over which was bad enough but half hour later I went a real purler. 
On the upside while I was down there getting my breath back and making sure that my previously fractured and plated wrist was still intact despite the pain, I glanced up at the roof and there was a tile completely missing and sitting in the gutter!!
Got a lovely young man from checkatrade.com to come round straight away. Cost £85 though.
It was a relatively simple job in itself but we have a conservatory and we weren't confident that we could squeeze through the gap with the ladder.

Then I sort of persuaded him that I needed new wood for my raised bed as it disintegrated as we were taking it down so just got back from B & Q and he's another £40 out of pocket.
I knew the Fluval was well over rated for the tank but it came with it secondhand so I had no choice.

How I wish I had gone with his original offer of a new one, but too late now the damage is done!!
Or at least got one from Ebay which meant that the seller would have been a bit more honest for fear of bad feedback.
We live and learn

UPDATE

The day can only get worse. I've just dashed through the kitchen to get on with my gardening to make up for lost time.  The knob on the cabinet got caught in my pocket and somehow I've RIPPED the door off it's hinges so that it is now standing on the floor next to the cupboard. O gawd

I'm seriously considering not getting up tomorrow 

Slapstick indeed.
The door isn't back on because in ripping it off I  completely destroyed the inside of the side of the cabinet the hinges fix to.

I was talking to my neighbours last night, over the garden fence as you do, and I mentioned the trials of the day culminating with the cupboard door.  I wasn't hinting but my neighbour gave me advice on how to fix the door back on using the cabinet that butts to it (he is a carpenter /joiner) and failing that he reckons he will do it for me. Result.

It is currently absolutely chucking it down so I am mightily relieved that the roof tile was speedily replaced.
The wood we bought for making new raised beds is now outside in the pouring rain which hasn't pleased the other half.  He has given it one coat of preservative so maybe that will help

No amount of reassurance on the part of my husband or the roofer I spoke to could convince me that we would not have had the rain inside because we have roof felt up.
It's water  -  it would have got in.

Thanks for the hint on the filter. Appreciated

(Good luck with persuation on the new tank front)