filter fix

Last week I put a question up on the forums. I decided to add polyester batting to the filter to remove fine particles, and thinking about where to put it- after the sponge, before the ceramic bio cubes- made me question how I've arranged all the media in there. I drew a few quick pictures to ask about the flow-

does it go mostly back-to-front around the corner of the filter box,

or bottom to top?

General consensus was that it goes both ways- but the picture I put up of my current media arrangement also got me some feedback that I have it in there wrong. For my particular model, the box shouldn't be crammed full of media, it needs space behind it for the water to spread out and flow through all parts of the filter panel. I felt terrible, and embarrassed, to know that I've been using it wrong all this time- over a year.

The fix: I bought some polyester quilting batting (called the company to make sure it has no flame retardant or other chemicals) and cut it to fit the media panel. I pulled out one sponge, and realized the two pieces I had in there were both shorter than the space, letting the water flow around it. So I really took out three-quarters of one sponge- the other part of it I cut to fit the width- flipping both horizontal and stitched together with fishing line so to make one larger piece the right size.

Sandwiched the sheet of poly batting between the plastic panel and the sponge, and held it together with two loops of fishing line. Just loose enough I can slip them off again for rinsing. It's good I did it that way.

I also put the bio cubes back in there, in a space in front of the panel below the outflow wheel. Tried to hold them in the spot in a mesh bag. Later in the day noticed some overflow through the spillway. Took it all apart again several times- it turns out the flow was blocked because the poly was doing its job! In just a few hours it had turned from white to dark gray/brown, and was clogged with gunk. I rinsed it out in tank water in the bucket, but still had a little overflow until I took the cubes out of the bag and just dropped them in the spot.

The tank water does look cleaner- visually there are far less particles- but when I tested it surprised at the result. I expected to get ammonia or nitrite spike from removing part of the sponge, but instead found high nitrates 80+. Maybe there was an ammonia spike and it resolved quickly into nitrates, or I inadvertently fouled the water when messing with the filter on/off. Regardless, I did a small partial wc and brought nitrates down to around 40. Tomorrow will do another wc.

The flow is a lot stronger. I might have to put the baffle back on. As soon as I had it going properly again, the cherry barbs were very active in the watersprite plants just below the outflow. I wasn't watching them closely but I am pretty sure they were flirting, sparring and spawning again. Next morning dismayed to find one of the females is missing half her tail. I can only think one of the other fish bit it in a fight. Keeping the water cleaner will help her heal. I'm also hoping this improvement might be enough to do away with the bits of thread and hair algae I still get. Will wait a week or so to see, before I try adjusting lights or ferts any.