How Can You Tell If Your Current Is Too Strong?

[Luixfern]

Hello all, I am new to the hobby and I recently acquired a 45g tank. It came bundled with a Aqueon 55g filter. My question is, can a filter meant for a bigger tank than the one I'm using cause an overly strong current? My fish seem to all hang out on one side of the tank (opposite side of the filter) and when they swim they dart around, rarely do I see them just floating in place as they do at pet shops. The filter doesn't have any sort of valve to reduce the current. Should I be looking into a new filter with some sort of control over the current or do my fish just need to adapt. I have a couple barbs and tetras if that helps. Thanks.

 

[fergalthefish]

if your fish get blasted across the tank then i'd say it's too strong lol seriously though a lot of fish like water movement plus it increases oxygen but too strong and they're permanently fighting it.

 

[xxBarneyxx]

I would say that filter is most likely fine for that size of tank (its doesn't have a massive flow rate on it). It depends on what fish you have though. Some fish love a really strong water current while others do not like any current at all. You can most likely attach a spray bar to the outflow of the filter which will not reduce the flow rate too much but will reduce the amount of water pressure.

 

[waterdrop]

Good question!
I agree with Barney, spray bar gives you greater options for reducing and directing the pressure, without necessarily reducing your filter turnover rate.

One problem with the question is that evolution has produced as many varied types of fish as there are wildly different water flows in nature. Think of times you've stood at waterfalls/rapids or sat near a very still creek backwater or pond. Also makes me think of some of the new videos I've seen on UTube where people have taken underwater movies of the actual same species we put in our aquariums but in their natural habitat - different sorts of flows there for different fish.

Another thought from a different angle is that if the fish are hanging back and then darting out, they may enjoy more cover. Some fish are used to very dense plant areas or varied caves and hiding places. The right habitat for some of these types can suddenly make them feel at home and change their behaviours.

Yet another thought is that if the fish were only recently introduced to your tank then their behaviour may be entirely different than it will be when they settle down. Some fish just stay scared for a relatively long time in a new environment. For some of them the environment is so foreign that they are just in life/death survival mode and not exhibiting their relaxed behaviour.

On the technical side - if you can manage to put a number (litres/hour) on the flow rate of your filter (not always easy, may involve contacting the manufacturer, although Barney may know) you can compare to rates commonly talked about here on TFF which I would speculate are roughly as follows:

Below 4 full tank volume turnovers per hour: little betta tanks?
4 turnovers per hour: Planted tanks with plants that don't like turnover
5 turnovers per hour: seems like the most average common suggestion here on TFF
6-7 turnovers per hour: tanks with messier fish or overstocked tanks

On a 45G tank, 225 gallons per hour flow rate would be 5 turnovers per hour.

~~waterdrop~~

 

[Luixfern]

Good question!
I agree with Barney, spray bar gives you greater options for reducing and directing the pressure, without necessarily reducing your filter turnover rate.

One problem with the question is that evolution has produced as many varied types of fish as there are wildly different water flows in nature. Think of times you've stood at waterfalls/rapids or sat near a very still creek backwater or pond. Also makes me think of some of the new videos I've seen on UTube where people have taken underwater movies of the actual same species we put in our aquariums but in their natural habitat - different sorts of flows there for different fish.

Another thought from a different angle is that if the fish are hanging back and then darting out, they may enjoy more cover. Some fish are used to very dense plant areas or varied caves and hiding places. The right habitat for some of these types can suddenly make them feel at home and change their behaviours.

Yet another thought is that if the fish were only recently introduced to your tank then their behaviour may be entirely different than it will be when they settle down. Some fish just stay scared for a relatively long time in a new environment. For some of them the environment is so foreign that they are just in life/death survival mode and not exhibiting their relaxed behaviour.

On the technical side - if you can manage to put a number (litres/hour) on the flow rate of your filter (not always easy, may involve contacting the manufacturer, although Barney may know) you can compare to rates commonly talked about here on TFF which I would speculate are roughly as follows:

Below 4 full tank volume turnovers per hour: little betta tanks?
4 turnovers per hour: Planted tanks with plants that don't like turnover
5 turnovers per hour: seems like the most average common suggestion here on TFF
6-7 turnovers per hour: tanks with messier fish or overstocked tanks

On a 45G tank, 225 gallons per hour flow rate would be 5 turnovers per hour.

~~waterdrop~~

Hey waterdrop, appreciate the reply. I don't think cover is an issue, its fairly planted and I added plenty of decor with caves and crannies for them to hide. I've had the fish in there for about 3 weeks now, I wouldn't think it would take this long for the fish to get used to their new environment. I had a couple die on me over night and when I go feed them in the morning I find them sucked into the filter as if they were too weak or stressed to get away.

My current filter has a 325gph rate. I went to the pet shop and asked the clerk the same question and she just replied "get stronger fish" which didn't help me much.

I was thinking about getting an Emperor 280 because I believe it has a valve that allows me to regulate the current, but I don't wanna make the expense if its going to make much diffrence. The emperor has a 280 flow rate, would that be better suited for a tank of 45g?

Sorry if I'm not making much sense here, Ive been up way to long