Divided Tank Filtering Problem

[Muffingirl333]

Hi there, new poster here. So, I found a thread on here about DIY tank dividers using the white crafting mesh and report binders. I successfully made myself a tank divider for my male and female bettas, but I'm noticing that the side of the tank that doesn't have the water filter is developing this nasty white film on the top of the water. I'm not noticing any problems with the betta on that side and I've just been skimming it off with a paper towel, but I'm wondering what I can do to get the water circulating better over there. I thought about cutting the divider down to just below the water level but then I'm concerned about one of them jumping over it. They both have been behaving very well and no one has attempted to jump the divider or push it over yet. Would it be better to just cut some larger holes along the water line? Or am I doing it all wrong having the divider sticking up over the water to begin with? Any tips would be greatly appreciated, thanks!

 

[SeanTrollope]

firstly what filter is it .

 

[Muffingirl333]

It's a Top Fin power aquarium filter, don't know much more than that. It sits on the right side of the tank. The rest of the water seems to be getting pushed through the divider just fine. But the top layer of water is stagnant.
http/m.petsmart.com/h5/hub?id=supplies%2Ffilters%2Ftop-fin-aquarium-power-filter-zid36-16953%2Fcat-36-catid-300088%3Fvar_id%3D36-16953

This is the filter I have.

 

[Wildbetta]

I recommend in this situation to place the filter where the outflow (waterfall part) is in one section and the uptake (the tube that sucks in the water) in the other section.  This helps with the water movement on both sides of the divider.  I do not in any way recommend you cut holes in the divider or drop it lower since both of those ideas will mess with the integrity of the divider and could let your bettas find a way into each others side.

 

[Muffingirl333]

Unfortunately that's not going to work with the design of the tank, the filter has to go on the right side where the cut-out on the lid is.

 

[Wildbetta]

Ok.  Then I suggest getting a sponge filter to put on the other side which will be the best way to filter both sides. 
 
These are the kinds of sponge filters I use on almost all my tanks:
 
http/www.ebay.com/itm/Bio-Sponge-Filter-Breeding-Fry-Shrimp-Aquarium-Fish-Tank-Double-Head-/171011983536?pt=Fish_Filters&hash=item27d11bc8b0
 
(NOTE - this link is not endorsing this seller but is just to show the product offered.  Also not to promote Ebay itself as these filters can be found on lots of other sites as well as possibly in some stores)
 
My personal recommendation is to ditch the HOB filter you currently have and just use two sponge filters run off of a dual outlet air filter.  The current created by a sponge filter is easier on a betta which is why they are the type of filter I recommend for bettas.
 
To use the filter I just showed -- you would need airline and an air pump.