Opinions and help please

So yesterday night taking a nice little look at my 5 gallon I noticed a couple things,Brown algae was coming back,My filter was not c leaning my water correctly and stuff was shooting out that was suppposed to be filtered.And what I could only describe as well you know what it looks like when oil and water mix?To make that rainbow thing.Yeah,thats what the top of my tank looks like but not filmy.And I wondered is this from my diy co2? So I took it out cause when I first put it in I had brown algae problems and oily looking surface So I think that is all good now.But any suggestions on what to do about the filter?

What filter do you have?

And also what media is inside the filter?
Order of media may help.

Aquatech 5-15 It may just need a good cleaning but here is the order.
In the front closest to the output is a yellow plastic filter piece.Then behind that is the big spongey media. Then to the side id the improller and tube and stuff.

My shrimp tank has the oil slick bad... I can skim it off and it comes right back...

I think my 5-15 aqua tech is one of the worst hobs I've bought... about 5 days and it can't pull water through its pre filter

Im =a just clean mine.

Having had a look online for this 5-15 aqua tech filter. It seems there are some reviews which does not favor this filter very well.

One of the suggestions given about this media is the plastic grate filter part is part of the problem. So folks have said just to chuck all the media out and replace with media of your choice.

I have done this with my HOB's, it was supposed to have cartridge filter media but I've never liked them whatsoever (always think these being a gimmick and instructions said to replace every few weeks, utter tosh imho) and instead took these out and just put in a small bag of ceramics/noodles under the input pipe and fill the majority of the space with sponge media and lastly on top, filter floss. I have done this for years and never have had any issues whatsoever. In fact it actually improved the filter all round and the tank water is crystal clear and no issues with water parameters whatsoever.

So thats what I would do if that 5-15 aqua tech was my filter, chuck the current media in there and replace with your choice of media. Of course do bear in mind if the filter is cycled, squeeze the media into the tank water and leave in a mesh bag in the tank for a couple of days to a week or so, just to transfer the beneficial bacteria into the new media in the filter.

Oh ok Well the blue media I know for sure Is ok I think As when I clean it, it always has junk on it I think it is just the yellow plastic part that is the problem so Ok I will just go pick up some filter floss or something and replace the yellow plastic part and then maybe put a little more in ther around the blue media just to help it.

http://www.petco.com/shop/en/petcostore/product/aquaclear-70-filter-insert-foam

Should this be fine to replace the yellow plastic thing with?

I've got one in one of mine.

I'm running two hobs with some 99 cent foam off eBay from Hong Kong. It's a little fine but It works.

Ok So the sponge will work.Good. Thanks toney and Ch4rlie