Filter outlet should be placed near (but under) water surface?

[bossteck]

Dear all,

Standby for a potentially silly question:

I noticed, through looking a pictures of most canister filter sets that the outlet of these filters are usually quite short in length, short as in, these u-shaped tubes often do not extend too far down into the tank.

Does it mean that it is common practice among hobbyists to place their filter outlets just a few inches below the water surface?

Would such a set up result in better circulation of the tank water? Compared to modification to extend the outlet further into the tank?

Cheers!

[Shadow]

I believe so because if you put far below near the gravel, the flow will be block by background plants. Background plant is usually taller. Unles you put it at the front glass or you have iwagumi scape.

[bossteck]

Hi Shadow,

I always have the impression that placing the outlet higher up in the tank would lead to higher chances of creating 'dead-spots' in the tank which poop will accumulate, and that lowering it would create better flow in spite of flow being partially blocked by background plants.

Cheers

[Aeon]

If you use fan, the water on top will be cool and convection will occur. It's flowing. My tank 4 ft length, 1.5ft height with outlet at the top back left. I can see debris floating at good speeds in all corners.

[PeterGwee]

A vertically placed spraybar return is a better way of spreading the current out evenly. Good tank water mixing is important especially in large tanks for CO2. Scapes play a big part in things so it's hard to give a general idea of what is best but you should have good current in all parts of the tank and moderate surface movement.

Regards,
Peter Gwee

[valice]

Vertical spray bar although good for spreading current out evenly, however, if the filter is too strong, you might encounter problems with plants not growing properly at the filter outlet due to high flow rate...

But then, it is really a very effective way of spreading around CO2 bubbles from a diffusor.

[PeterGwee]

Vertical spray bar although good for spreading current out evenly, however, if the filter is too strong, you might encounter problems with plants not growing properly at the filter outlet due to high flow rate...

But then, it is really a very effective way of spreading around CO2 bubbles from a diffusor.

What makes it different from a ADA lily pipe then? Same high current as well with a large filter. Some customisation is always needed along with common sense I guess.

You can customise a spraybar by plenty of methods (drilling more holes / larger holes and etc to reduce velocity but will maintain flowrate or splitting the outlet to more spraybars via Y or T pipes and etc.).

Regards,
Peter Gwee

[bossteck]

Hi Peter,

Thanks for sharing your insights!

[Biotopeshop]

We hope it does not turn out to be a "spray bar vs ADA lily pipe" thread

Both are meant to aid water movement, bringing nutrients to the tank. ADA lily pipes help to create a mini-cyclone at the water surface, as we can often see surface water that spirals downwards into the opening of the lily pipe. This brings along the surface protein that we often comment about the "oily layer". Hence reducing the need for a protein skimmer.

Both spray bars and lily pipes are capable of bringing nutrients to the far corners of the tank too, except that we do not shift the lily pipes but we have to make adjustments to the depth and direction of the spraybars.

We also agree that mini-customisation to the spraybars can also produce stunning results, but in our course of selling, there are also another school of hobbyists that prefer aesthetics and convenience.

cheers