Originally Posted by Dawes
Filter Flow Vs Air Pump Water agitation.
Iíve recently bought the newer Model Fluval Roma 240 (With new model 305 EF along with it)
The filter spout outlet reaches just below the water level and can be adjusted so that there is quite a lot of water agitation, how good is this compared to such agitation as Air Pumps?
The water flow at the top of the water is similar to that of a Wavemaker, as it makes quite a large stream/spray surface area of ripples ontop.
Would the filter agitation be sufficient enough? Or would I Ėneed- to use my Air Pump too? (Eheim 200 L/H).
I only intend to keep peaceful Barbs, a Gourami and maybe a Rainbow Shark/small Species Pleco.
Filtration and water current should be designed to suit the fish species, as not all fish are the same in their needs. Someone mentioned plants and this is another important factor; a well planted tank needs less actual "filtration" and a minimal to moderate water flow. But this may be impacted by the fish needs.
Taking only the named fish, You don't want much current in the tank [though the exact species of barb could change this, you have only said peaceful barbs] and gourami do not appreciate currents. But you should not combine gourami with barb anyway, as the latter will be more active swimming and this is not a good match with sedate fish like gourami.
Some pleco occur in fast-flowing rivers, some in very quiet streams and flooded forest, so here again the species is important. Sometimes it is possible in large tanks [I assume this is a 5-foot tank at minimum] to offer some variation. In my 115g 5-foot tank I have mainly sedate fish that do not appreciate currents. But I also have a trio of Centromochlus perugiae which absolutely must have some current. I have been able to satisfy this need by placing a standing chunk of bogwood with tunnels right at the left side very close to the filter return. It is a Rena Filstar XP3 and I removed the spray bar to use the spigot, and it is on the back wall about 15 inches in from the end wall and aimed directly at the wood. This gives the cats just what they want--and within half a day after being introduced to the tank, they all took up residence in this wood obviously due to the current; but the flow hits the end wall and then is significantly slowed so that down the length of the tank is is barely noticeable; none of the plants move at all. This is ideal for the other fish (Bolivian Ram, several quiet tetra, corys, whiptails).
The Rainbow Shark is nice, but notice in the profile that this will limit other substrate fish.
Many mistakenly choose a filter without regard to the fish, so here you are going about this the correct way. Hope the above is of some help.