Filter Positioning The Cause Or Solution?

[Guest22583]

At first I set my tank up with the filter at the bottom of the tank, as a beginner to this stuff would assume.

After a small while, the surface slowly starts showing signs of buildup, possibly bacteria? I can't remember what the guy at one of my local aquarium shops said it was because he was explaining to my girlfriend (guys try so much harder for girls ) and so we take out one of two white filter sponges we had in the filter. The filter came with both in so we assumed they both stayed in there. Now saying 2 sponges I don't mean the carbon filter. That's the black one we have. He also said it was an excessive growth of 'helpful' bacteria and was something called 'new tank syndrome'. He sold us a bottle of Nutrafin B-Clear.

Now we took one out and the build up got worse and the water was getting milkier and milkier. The B-Clear worked for a short period but still left the surface with this build up.

This is a greyscale photo of the surface, looking up from outside

There was also a build up of horizontal residue on the glass surface. I just rubbed it with a broken surface thermometre we have and they came right off with no effort, suggesting they're bubbles. But they aren't my problem in this topic.

We went to a different (and better stocked and maintained) aquarium who employed staff who really knew what they were talking about. The one guy who spoke to us had kept fish for 11 years and also works as 'freelance' as an aquarium maintainer for £25ph so we had no reason to doubt him.

He had a think, asked some relevant questioned pondered some more and told us the problem was the filter wasn't moving the water around enough so there was a build up of crap on the surface. He said to raise the filter so there is alot of movement on the surface.

We were also due for another Weekly Nutrafin Cycle supplement, so we put this in. It's be a few days and the water appears to have cleared up dramatically:

This is a greyscale photo of the surface, looking up from outside

However, is the surface supposed to be moving this much? It may have got rid of the crap on the surface but does it render the tank unhabitable? Will the bubbles stress my fish or is this all ok? Also does anybody know what the gunk on the surface could be?

To help show you the effect of the filter just below surface level, I made a quick movie clip -

 

[Chri$]

Your filter is now positioned correctly. The more surface agitation the more dissolved oxygen which means happier fish.
No, the bubbles do not stress your fish. If you don't want quite as much surface movement just position the filter slightly lower.

 

[BrassMan]

I have a Flouvel 4+ which is the same as yours only bigger. The bubbles are fine but if you don't like them you can tune them out by twisting the dial on top of the venturi valve (the black thing sticking up from the filter outlet), as long as the filter is still producing some surface turbulence the water will still be airated, if it looks like your fish hav'nt got enough O2 then you can dial the bubbles back in to provide a little more surface movement.

Paul

 

[Chri$]

I have a Flouvel 4+ which is the same as yours only bigger. The bubbles are fine but if you don't like them you can tune them out by twisting the dial on top of the venturi valve (the black thing sticking up from the filter outlet), as long as the filter is still producing some surface turbulence the water will still be airated, if it looks like your fish hav'nt got enough O2 then you can dial the bubbles back in to provide a little more surface movement.

Paul

Or you can take the venturi attacment off.

 

[BBrain]

Now that your filter is okay, what wattage is that l-o-n-g heater, and what volume is the tank?