Is the Cascade 300 hang-on filter low-flow enough for a betta sorority?

[Mint]

Anyways, I’m planning the sorority so far, and I’m trying to find a filter low-flow enough to be fine in a sorority. I’ve used Cascade before, and it worked fine, but I’m not sure if it would be peaceful enough for a sorority of bettas, plus whatever dither fish I end up going with. Both of those will probably need very low flow, so the filter being low-flow would be good. This is a 40 gallon breeder tank.

 

[10 Tanks]

Hello. If you keep the water really clean with large, weekly water changes, you won't need an expensive filter. That's because the filter will just be filtering water that's already clean. Go with a simple sponge filter. That will be enough to move the water around the tank and maintain a good level of oxygen. The water change is the true filter. A 40 gallon tank just needs half the water changed out weekly. Remember to feed a little every day or even two and you'll have no tank problems.

10 Tanks (Now 11)

 

[Mint]

Wouldn’t adding too much water at a time just kill your fish?

 

[Slaphppy7]

Wouldn’t adding too much water at a time just kill your fish?

Not if done correctly.

 

[Mint]

Are you supposed to stagger the water changes over a week?

 

[10 Tanks]

Hello again. If you haven't reached the point where you're removing and replacing half the water weekly, then you need to get there gradually, Every week, remove and replace a little more water. The gradual change in the water chemistry won't harm your fish. Don't suddenly change a lot of water. The shock of a sudden change in the water chemistry can hurt the fish.

10 Tanks (Now 11)

 

[sharkweek178]

I use this trick to disperse the flow from my HOB filter and it works great.

 

[seangee]

Are you supposed to stagger the water changes over a week?

No. When you remove 20% of the water you are leaving 80% of the bad stuff behind. I once saw a great video explaining this using a cup of tea. Can't remember where but take a cup of tea and replace 10% of the water. Repeat until the water is clear. How many water changes did you need? Now repeat with 50% changes. FInally repeat with 75% changes. The difference between fish tanks and teacups is the fish are adding back more bad stuff in between water changes.

FWIW this was my 200 litre tank earlier today (and this happens every weekend)