DIY filter current reducing...

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Aquarium Advice FINatic
Aug 27, 2008
Southern CA
So here's my dilemma.

I have an 8gal with quite a bit of filtration and current. The inhabitants do fine (tetras and cories). They have figured out it's kind of fun to zoooom through the current and do loops around the driftwood arch and then rest up in the terra cotta pot... and do it again.

Time to upset the status quo: I rescued a female betta the other day... so now I need to figure out how to get her a low/no-current area in my 8gal because I don't want to keep her in the betta "tank" any longer than I need to (aka until it's established she isn't sick- so far it looks like she just needed some good fresh water...)

I've thought about attaching sponges to the outflow and intake to slow the water rate down- a possibility still but I'm not sure if a regular kitchen sponge would work or would have been treated with something not so good for the fishies... or if it would break down at some point and I would have to be cleaning little bits of sponge out of the tank and filter (ugh).

My dad suggested somehow creating a barrier at the water surface that drops down 2-3" to create a 'breathing/hangout spot' for the betta. I'm still thinking on how to accomplish this. There's one corner that I think would work pretty well with this idea, I'll try and sketch it out.

I can't use the soda bottle trick- it's not a HOB filter... the media is horizontal in the tank lid- water fountains on to it through a tube with holes that rests above the media. I'll work on pictures. It's a Jebo R338 with a flow max of 400L/H if that helps. (Came with the tank kit... otherwise I would just replace it with an adjustable filter, but the tank lid is designed around it so it's a last resort really.)

I am working on getting a lot of tall plants, hopefully ones that have ends that will be long enough to clump/pool at the surface... so that should help provide a still-er betta friendly area, correct?

I would rather not cut my filtration if possible.

Sorry if this is ridiculously confusing... let me know and I will try to clarify...

A second tank is not really an option unless the betta just doesn't get along with the other fish.
Can you direct the flow of the water output? <say moving that "spray bar"> A favorite trick of goldies keepers is to direct the water current down the back of the tank, the front would then be relatively calm. <I am not sure if this will work in an 8 as it is pretty narrow front to back - most people do this in 80+ gal tanks with 16-20" between the front & back.>

Another idea is to have a big tall piece of driftwood (or other decorations) to block/redirect the water flow in one part of the tank to create a calm spot.
The 'spray bar' is holes in the bottom of the lid underneath the filter media... not really tilt-able. :/

I could possibly attach something that directs it back or to one side however. That's not a bad idea.

I just added a bunch of plants and I'm seeing more where the current is- there's a LOT of it. Oh, and now I know why my tetras don't come out from the back corners much. They get tossed around anywhere else!

There's also a random shoot of water coming out of the pump part of the filter- it can be used to add air bubbles but it's a ridiculously powerful stream... I tried blocking it with one finger and didn't see any difference elsewhere. I will do my best to get photos of the whole setup today.

I've looked for more info on this filter (it didn't really come with instructions) and I can't find ANY. Ugh. Will know not to buy this kind of tank again- the filter's just too strong and apparently not adjustable.
OK: is this a decent filter?

Aquarium Filters: Whisper In-Tank Filters

If I can't modify what I have (or it will be really expensive/difficult to do so) then I can swing a new filter if it's inexpensive. I'd like to keep a really high level of filtration- anyone know if the current on the 40gallon version is really strong? or would the 20 gallon be adequate (it's an 8 gallon tank but will probably be pretty heavy on the bioload when I'm done)? It is a well-planted tank and I'm considering adding some more plants- as it is my nitrates stick to about 5ppm and ammonia/nitrites are always 0.

I'm a little limited since I can't have an HOB filter.
Get an AC filter(aquaclear) you wont be sorry, these have adjustable flow also.

I think you should make the holes larger on your current filter as this will be less strong
SpeedEuphoria, I can't have a HOB filter, as is mentioned. No room behind the tank and the lid does not allow for it.

The AquaClears are HOBs (unless my google searches are inaccurate).

They are also at the very edge of my budget (college student here) unfortunately.
just make the spray bars holes bigger, Its hard to say as I cant fully picture the filter you have and how it works exactly. (pics would help)

Otherwise for an 8g a sponge filter
As I said I'm working on photos...

There isn't a spray bar, really, and I'm not sure if I could make the holes bigger. I'm in a college dorm- I don't have access to tools and I can't exactly take the setup home for the weekend being as then the fish would be without a filter for several days.

I can probably hot glue something to redirect the water, but that's about it.

Another thought I had: the water is 'fountained' on to the filter media via a tube with several large holes in it- if I somehow blocked or partially blocked these to reduce the amount of water, that could work, but would it damage the pump? (I'm assuming I'd also have to somehow slow down the intake.)
OK: photos!

Upper left: holes (the dots of color essentially- bad photo, sorry) are the water outlets, media removed. This is in the lid.
Upper right (is sideways for some reason): Water runs through the clear tube and is released onto the filter media via holes in the tube. (The end is just out of the photo)
Bottom left: water outlet taken from underneath.
Bottom right: filter. The outlet just below the airline tubing sprays water at a pretty good force and will bubble if the cap on the airline tubing is removed. There was no explanation for this so I have no idea what it's for... it puts out a LOT of air bubbles though and is kinda loud.

I did a bit of tinkering and may have come up with a solution, time will tell...

Under the tube where the water fountains out on to the filter media, I put half of a soda bottle (more like a third, I had to trim it down so it would fit under the lid) to slow the water down.

I took a water bottle top (the sport-top kind), took off the moving part of it so the water could pass through relatively easily but at about 2/3-1/2 the volume, and tucked it in the basket intake.

So far the current is less enough that the tetras are coming out of their hiding space. Don't know if it'll be enough for the betta...


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Be careful with how you redirect flow inside your filter. If you start routing flow so it doesn't flow through the biomedia properly, it will not do its job as it should. The little tube on the side of your water pump is to bring air into the aquarium. If you can stand the noise it makes, the flow will be much lower if you open up the air valve. The energy used to pump the air slows the water flow. My power heads have a nozzle like that on them and came with a flow diverter that clips onto the nozzle. With that flow diverter I can direct the flow where I want it in the tank. Maybe there are bits that came with your tank that are sort of fan shaped that are made to go on that part and would slow and spread out the flow coming out of that hole. I would not plug the hole unless you know for sure that there is enough flow through other paths to keep the water pump from overheating. If the pump just recirculates the water that is trapped in it, it will overheat eventually because the pump energy that can't be used to move water will be converted to heat.
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