HMF (Hamburg Mattenfilter) Questions

**zonkkie** · 4th May 2011, 22:24

Dear all,

I have setup HMF (http://www.janrigter.nl/mattenfilter/) in 2 of my tanks. I do notice a couple of things which I hope someone can help.

1) As done by many others, I hid my heater in the HMF. However, I notice a temperature difference in my HMF and the tank water. 1 degree difference. Not sure if it means my flow is too low. Tank is around 100 liters and the airpump I use is rated 200L/h.

2) After more than a week of cycling, there is surface scum on the HMF side. Anyway to get rid of it or should I just leave it there since it doesn't affect anything.

**bernie** · 9th May 2011, 13:22

I see people use powerheads rather than airpump. Maybe that makes a difference?

**jeffteo** · 9th May 2011, 16:33

Curious why you need a heater in Singapore? Tank is In a 24/7 air-con room?

Let's see if I can help.
1. The sponge used is an insulator thus the side where the heater is placed will always be warmer.
2. Air bubble is not a good conductor of heat. If you are using air to drive it, you will need very high flow rate to mix the water fast enough.
3. Hot air/water rises and this will means the heated water is always at the top. Where is pipe drawing water in from, near the top or bottom?

For surface scum on HMF side, i think is is ok as it is not affecting oxygen exchange. If you want to break it up, just add another air line tube in at few bubbles per second to break up the surface.

**bernie** · 9th May 2011, 18:02

Originally Posted by jeffteo

Curious why you need a heater in Singapore? Tank is In a 24/7 air-con room?

Let's see if I can help.
1. The sponge used is an insulator thus the side where the heater is placed will always be warmer.
2. Air bubble is not a good conductor of heat. If you are using air to drive it, you will need very high flow rate to mix the water fast enough.
3. Hot air/water rises and this will means the heated water is always at the top. Where is pipe drawing water in from, near the top or bottom?

For surface scum on HMF side, i think is is ok as it is not affecting oxygen exchange. If you want to break it up, just add another air line tube in at few bubbles per second to break up the surface.

Let me guess. Because of the type of fish Zonkkie is keeping.
Using a higher flow rate might help. Or move the heater to be with the fish.

**zonkkie** · 10th May 2011, 15:19

Thanks bros.

1) Hiding heater is for asthetics la... of course can put with the fish worse comes to worse. For HMF, water turnover rate is recommended 1-2x so cannot have too high flow rate, else the bb in the sponge will not work.

2) Need heater because of fishes - plecos.

3) Changing one to powerhead instead of airpump and will see if it makes a difference.

**jeffteo** · 10th May 2011, 16:56

Sorry to side track. So Plecos need warm temperature above 28 degree C? Or need a stable temperature?

Changing to powerhead, won't that increase the flow rate also though it carries more water than air.

**cylap888** · 8th Jul 2011, 10:37

What type of filter material did you use? Where did you get it. Intend to set up also.

Thanks.

**stormhawk** · 8th Jul 2011, 11:07

To set up a HMF, all you need is basically a large piece of coarse/fine sponge that can wedge tightly between the front and back panels of the tank. I think any LFS will stock such sponges of variable size.

About the surface scum on the HMF side, you can break it up with an airstone or a surface skimmer attached to a HOF. Water circulation is just as important behind the wad of sponge as it is on the other side where the fishes are.

**BillD** · 12th Jul 2011, 01:37

One of our members has 34 tanks running 20 PPI reticulated foam matten filters, the largest being 350 gallons. All are air powered, and with the proper configuration can move a lot of water. They go a year or more between cleanings.
As far as temp goes, 1 degree is really no consequence.

**BFG** · 12th Jul 2011, 04:25

Different countries experience different kind of climate. Here in Singapore, if you switch off the fan or air-con in an enclosed room, the temperature may rise during the day due to the hot weather. It become worst during the hot spell. Chiller and air-con will have to work hard during this period and many will fail due to heat load.

**cylap888** · 12th Jul 2011, 14:01

Anyone knows which LFS selling the 20 or 30 PPI reticulated foam?

**zonkkie** · 12th Jul 2011, 17:05

I used the black coarse foam from Ocean Free. Not sure how many PPI it is but it works. Got mine from Seaview but most LFS has it... Y618 and C328 have.