[Erloas]

I've got a 25gallon tank that I'm setting up for breeding. It is 24"x24" but only about 10" tall. With substrate its only about 8" between the substrate and the surface.

I'm going to run a sponge filter in it because I've heard thats a lot better for fry and shrimp. I'm going to start by breeding red cherry shrimp, then I'll probably do something else later.

So I picked up a 40g sponge filter, put it in my main tank and left it there for 3-4 days so far. First question is, how long will this filter need to be in the main tank before it will have enough bacteria to put in the small tank and get it running with little to no cycle.

Second question is that the sponge filter is almost 10" tall from the base (without extension) to the top of the lift tube. Which is going to put it out of the top of the water, maybe even above the rim. I'm going to need to keep a glass top because of my cats, and because its really dry here and without a lid it looses a lot of water to evaporation pretty quickly and my lights don't have covers to protect them.
So it might be ok if I bury the bottom of the filter in the substrate, or if I cut the lift tube down a bit, or maybe some of each. I'm thinking if I shorten the lift tube it will cut down how much water gets forced through the filter. I could also put an air stone on air hose and stick it into the sponge filter instead of the bull's eye which should give it more distance to move air up and move water.

What is the better option here?

 

[non_compliance]

I don't think it's any problem to cut that plastic tube. I have done it many times. If you don't want to do that, just tilt the sponge filter and hold it down with a rock or something... you still want that tube to be angled up, but you can use a piece of slate or something to hold it against the back glass.

As far as seeding it, I wish I knew... but I always keep an extra sponge filter running in one of my tanks so I can just swap it out and put up a new tank on a moments notice. Probably a week or 2 to get a good colony of bacteria in the sponge.


Good luck.

 

[Karackle]

I would try to set the filter on the very bottom of the tank and then cut the lift tube down to size. You want to try and make sure the top of the lift tube stays below the water for the most effective use of the filter. It should still draw enough water through the filter.

As for the starter bacteria colony, it also really depends on how many shrimp you plan to start with. RCS have a VERY low bioload, so if your starter colony only has a few shrimp in it, a few days in the tank should probably get you enough bacteria. Especially if you throw a few stems in there.

 

[[email protected]]

A couple of weeks to seed but ...
Fry and shrimp are low bio-load.

If your sponge is a Hydor, you can cut the tube down to a couple of inches and still get good water flow. One thing that will help in your situation is to not use the top connector for your air line. If you pull filter apart and insert an air stone in bottom and thread the air line out the top you'll improve the flow. Unless your air pump blows the air out the sponge instead of up. ;-)

If you can, multiple smaller sponge filters would provide better coverage for this tank, and allow you to keep a "hot spare" on hand for future needs.