Intake tubes on HOB filters

[CACAdmin]

I have often wondered about the length and placement of intake tubes on HOB filters. On large filters they tend to be quite long but on the small filters there is little distance between the intake and the outflow from the filter, making me wonder how much tank water is entering the intake and what percentage of that is already filtered water from the outflow.

I realize there are extension tubes sold for some filters (or if the intake is a round tube, you can extend the existing tube with hose) to enable you to place the intake closer to the bottom of the tank (further distanced from the outflow).

I was wondering if it might be better to extend the intake not only to the bottom but a distance horizontally as well away from the outflow? Has anyone done this? Is it beneficial to the filtration or are there factors I'm not considering?

[OldMan]

I usually try to get my HOB filter inlets as close to the tank bottom as I can without sucking up sand. It seems that the smaller filters are made for smaller tanks and there is really no room for longer inlet tubes. I actually got one of the new whisper series filters that is made for a 20 and it is slightly tilted because I put it into a bare bottomed 10 gallon as an attempt to get a little more filtration for that tank. My larger HOB filters have mostly come with some extension sections for the inlet and I get as many sections as I can onto them while leaving a couple of inches of clear space from the substrate. I have never tried to take my inlet sideways in the tank but would expect that to be difficult to do without lots of extra suction cups to guide the inlet strainer to the place I wanted it.
When I look at the return flow on my HOBs it seems like it really does not return downward as much as it returns almost horizontally across the top of the tank. By keeping water levels high, I don't think I get much vertical return of water so I still get decent mixing.

[OldMan]

Sorry duplicate

[CACAdmin]

I guess only way to really see the flow would be to test an unoccupied tank by filling the HOB reservoir with colored water and then turn on the filter and observe. As I don't have an empty tank and filter which is not being used and wouldn't want to run this type of test even with food coloring in an occupied tank, it's hard to know for sure. However, I agree that it appears that a great deal of the flow appears to be horizontal.

If one wanted to redirect the intake without a dozen anchors to hold the extended intake in place, here's something which should work: http://www.modularhose.com/Loc-Line.htm. It's aquarium safe and will hold whatever position you place it in.

[Noctame]

Can foam be put around the intake of an HOB or Canister filter to soften the suction? or protect fry?

[OldMan]

To protect fry, I use a piece of filter foam with a slit cut in one end and slipped over the inlet tube.

I use one of these.
http://i290.photobucket.com/albums/ll251/Oldman1947/Heterandria/DrySponge.jpg

In place it looks like this after about a month.
http://i290.photobucket.com/albums/ll251/Oldman1947/Heterandria/SpongeInPlace.jpg

The one in the picture is in my Heterandria formosa tank.

[CACAdmin]

I always keep a sponge over the intake tube of my fry tank to keep them from being sucked up into the HOB filter. However, that doesn't keep them safe from me doing something like this (http://www.canadianaquariumconnection.com/forum/showthread.php?t=5925). :rolleyes:
I also find the fry like to nibble on the microrganisms that collect om the sponge.

[blainep]

I use extra tubing to extend my filter intake tubes. I use AC HOBs exclusively now so getting extra lengths is no problem.

I often use media bags to cover filter inlets in many of my tanks. They seem to work pretty well overall.

[mdfa.ca]

Jay,

I have often wondered about the same thing and am glad you have mentioned this. Couple more factors to consider:

1. Natural turnover of water. As the top layers of water cool due to evaporation they will naturally sink displacing the cooler water below them, thus creating a slow but sure natural water turnover. Now I would certainly NOT depend on that alone to assure all the water has been filtered well as this process is very slow.

2. The strength of the filter outflow. On my 20 Gal tall, I have two HOB filters. One is a Marineland 10 Gal and an AquaClear 20 I believe. The AC has a very short intake and so did the Marineland, until last night, when I put an extension on it.

Why? When I feed my tetras (that's all that is in the 20 G Tall) flake food in the morning, I usually just throw the flakes into the outflow of the filters, as they like food that swims through the water column. They can then easily dart around and catch it in a way natural to them. I noticed flakes thrown into the AC outflow go right to the bottom of the water and then disperse horizontally and back again. IN other words, there is an excellent water mixing thing going on from that filter's outflow. However, the Marineland outflow is very weak compared and the flakes that find their way under it just kind of reach the middle of the water column before going back up again. So the outflow from this filter isn't as strong and hence the extension tube.

In conclusion... (LOL), I'd say if your outflow is good and reaches the bottom (test with flake food), you are probably OK with intake tubes being anywhere near the middle, but if it's low, I'd suggest putting extensions on.

Margaret.

[fishclubgirl]

I went to a local cichlid breeders and he had all of hob filters with extended tubes. Seeing that, I went home and extended all of mine(10 and 20 gallons). Bad idea!! All of my tanks are heavily planted and they got clogged so fast. So in closing, I suggest trying it but observe the results.