# Hamburg Matten Filter



## jameson_uk (23 Jun 2020)

When setting up what is currently a fry tank I bought a HMF.

The sponge fits pretty tight so the tank so I have just wedged it in and have added fine sand only on one side. There shouldn't be a need to do anything more substantial?

I have added the heater to the area behind the filter but noticed that the temperature in the tank was cooler than the filter area, presumably increasing the flow will help here.

I have noticed what I guess is a protein build up in the filter area. I guess with no surface agitation this is expected. Should I be doing anything other than a little cleaning at water change time to prevent this?


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## mort (24 Jun 2020)

You have pretty much diagnosed and solved your problems, so there isn't really anything to suggest.


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## jameson_uk (24 Jun 2020)

mort said:


> You have pretty much diagnosed and solved your problems, so there isn't really anything to suggest.


Just seemed odd in everything I have read about HMF I haven't really come across anyone talking about protein build up in the area behind the filter so was't sure whether I should consider putting an air stone in there or whether the uplifter should have some sort of small bypass to just agitate the surface a little.

As it is a fry tank I have thought that moving the heater in the main tank area rather than upping the flow so the fry aren't blown all over the place.  I a just surprised as to how well an insulator the foam seems to be and it seems the main tank is about 1.5C less than the area behind the foam.


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## mort (24 Jun 2020)

jameson_uk said:


> Just seemed odd in everything I have read about HMF I haven't really come across anyone talking about protein build up in the area behind the filter so was't sure whether I should consider putting an air stone in there or whether the uplifter should have some sort of small bypass to just agitate the surface a little.



I think some of this is because hmf's are run by fish nerds in their breeding setups, so lots of live and frozen foods are fed that don't necessarily create a protein film like most fry foods do. I'd also wager that most don't notice any film if there is any as they run them at the back of the tanks in the dimmer areas. Your solution of adding more aeration to that area does work and I have a little air bleed in my just to keep the water circulating. I don't think a little bit of protein film is a problem but if you want it shifted then it is easier to add a new outlet.

I'm surprised there is that much difference in temperature, unless the flow is really restricted but moving heater should help if it's put in an area of high flow.


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## sparkyweasel (24 Jun 2020)

jameson_uk said:


> the main tank is about 1.5C less than the area behind the foam.


If it stays like that consistently it's not a problem, you can set the thermostat accordingly. You might check whether it just gets hotter behind the foam when the heater is on, and the main tank area gradually warms up to match. You don't want a lot of fluctuation as it's a fry tank.


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