Can Coop sponge filters be run from the bottom?

[ChefConfit]

So say I was thinking of drilling the bottom of a tank to run airline that way in order to hide it. It doesn't seem that it would require modifications other than just not using the base iirc there's actually a  spot on both ends to connect airline but I just wanted to check. Is there any reason it wouldn't perform as well in that configuration? 

[lefty o]

i cant imagine doing all that, but the way i see it, as long as there is air flow going up through the tube of the filter it will draw through the filter.  it should work.

[gardenman]

I would prefer to never drill the bottom of a tank. When something goes wrong in such a situation, the whole tank drains. There are easier ways to hide airline tubing.  You can simply silicone it into a back corner and then run it along the back bottom of the aquarium and even include elbow and tee fittings with short airline tubing stubs with plastic air valves to feed current, and future needs. All of the stuff along the back wall can be siliconed in place and buried in the gravel. Someone would really need to search to figure out how you got air down there. It's easier to hide the airline tubing than the sponge filter. You can buy all kinds of airline tubing fittings these days. Two ninety degree plastic elbows, one to turn the airline from vertical to horizontal at the corner where it's glued in and the other at the far end with an airline tubing stub and valve. However many tees and valves you might want for future expansion, one every eight to twelve inches seems about right. All of that except for the tubing coming down in the corner could be hidden under the substrate and invisible. Need to add an airstone later? You know where the available stubs are, simply dig through the substrate, find the valve, open it to blow out any substrate, close it, attach the airline tubing to the airstone, adjust the airflow using the valve, cover everything back up with the substrate. Boom! You've got invisible air wherever you want/need it.

[Paul]

9 hours ago, ChefConfit said:

So say I was thinking of drilling the bottom of a tank to run airline that way in order to hide it. It doesn't seem that it would require modifications other than just not using the base iirc there's actually a  spot on both ends to connect airline but I just wanted to check. Is there any reason it wouldn't perform as well in that configuration? 

If concealing  the air lines is the issue CoOp sells black air lines. No need to drill especially the bottom of your tank. 

[RockMongler]

It would probably work.  Biggest worry (outside of the risks associated with hole on the bottom of your tank) would be making sure the bubbles don't spread too much side to side, so they start coming out the filter not through the riser tube. But, a bit of tubing going up to an airstone from below should get you the same results as the air line coming in from above.

As to the fear of drilling the bottom of your tank...  I was under the impression it was a moderately common practice in ye olde days when undergravel filters were the main form of filtration, so you could use gravity to flush clean gunk out of the bottom of the system through that hole in the bottom.  Perhaps some of the more seasoned and experienced members can chime in on that?

[gardenman]

13 minutes ago, RockMongler said:

It would probably work.  Biggest worry (outside of the risks associated with hole on the bottom of your tank) would be making sure the bubbles don't spread too much side to side, so they start coming out the filter not through the riser tube. But, a bit of tubing going up to an airstone from below should get you the same results as the air line coming in from above.

As to the fear of drilling the bottom of your tank...  I was under the impression it was a moderately common practice in ye olde days when undergravel filters were the main form of filtration, so you could use gravity to flush clean gunk out of the bottom of the system through that hole in the bottom.  Perhaps some of the more seasoned and experienced members can chime in on that?

I'm 62 years old and have been keeping fish since I was six or so, and I've never heard of anyone drilling holes in the bottom of a tank for an undergravel filter. The older style of overflows with the internal weir used to have bottom holes, but that's about the only time I ever saw holes drilled in the bottom of a tank.  The weir would, in theory anyway, prevent the whole tank from draining should there be an issue with the bottom seal on the hole. The water would drop to the top of the weir and stabilize there. Drilling a hole into the bottom of the tank without a weir to stop a flood is pretty risky stuff.

For those who don't know the weir is like a dam with a screen or gated opening at the top to allow water in. That area behind the weir stays dry until water reaches the inlets at the top of the weir. Should there be an issue, water would only drain down to the opening at the top of the weir and then stop, preventing the whole tank from draining. There were corner weirs (the most common), back weirs, and even center weirs on bigger tanks. A hole in the bottom of a tank without a weir is a recipe for disaster.

[starsman20]

This is correct. You are asking for trouble putting a hole in the bottom without a weir.

[Daniel]

@gardenman I have a center standpipe. Is that like a weir?

I have 4 holes drilled in the bottom of my tank.

Looking South:

Looking North:

[gardenman]

A center standpipe could be a weir. Think of a weir as a dam. It's typically glued in and sealed so water can only get in from the top. That way if a connection under the tank fails, only a bit of water comes out instead of the whole tank.

[Daniel]

26 minutes ago, gardenman said:

A center standpipe could be a weir. Think of a weir as a dam. It's typically glued in and sealed so water can only get in from the top. That way if a connection under the tank fails, only a bit of water comes out instead of the whole tank.

I guess my center standpipe isn't a weir. Water does go in from the top but if I knocked it sideways it would drain the entire tank.

But maybe it is a weir because I could slice the hose underneath the tank and no water would drain.

But any water that goes down under tank (at least through hoses) either has no place to go, or goes to the pond outside.

[ChefConfit]

So the "tank" I'm thinking of doing this with is actually a 7 gallon cylinder and the base is 1 inch thick. Given the low volume and thickness of the bottom glass I'm not very concerned with the bottom losing integrity or seals failing. I'm planing on using it for a planted vase and don't want any cords or tubing coming up through the opening, but not sure if I'm confident enough to go no filter. The idea for the tank came about when I saw a similar vase at a craft store and immediately thought of an antique piano lamp I have in storage that would look awesome lighting a small planted tank. 

[Daniel]

2 minutes ago, ChefConfit said:

I'm planing on using it for a planted vase and don't want any cords or tubing coming up through the opening, but not sure if I'm confident enough to go no filter.

I have big tanks and little tanks with no filters. The only way to know if a no filter tank would work for you is to try it. My hunch is the odds are in your favor. And if it doesn't work, you can always blame me.🙂

[CanadaAmanda]

I've just started up a cylinder tank, 25" high, 10" wide.  I have a heater cord and airline tube going in, but they're reasonably well hidden from the main viewing angle by driftwood, and I've put in some house plant clippings at the top which helps as well.  I'm going to put a frosted background on it which will further hide them.  I chose an undergravel filter to minimize the space a filter took up and hopefully also minimize maintenance as it's well planted - mulm should feed plants and my hardscape is easy to remove if I do need to get all the way down to the bottom for trimming, etc  The main thing most folks have against UG filters is the difficulty of cleaning under the filter plates.  If you had it drilled on the bottom, you could drain out the gunk.

 

@Daniel in your unfiltered tanks - do you have an airstone?  I have a 2.5 gallon that has an internal filter but low surface agitation... it's fantastic for floating plants but I'm starting to see a film on top of the water.  I do water changes on it 2-3 times a week anyway, but I hear it reduces gas exchange and I wonder how you get around that film in a tank without any filter/airstone/agitation?

[CanadaAmanda]

One other thing to note is that the cylinder once filled with water will hide things at the edges (obviously that will move as your viewing angle does) and magnify things in the centre, so you can perhaps place some things strategically to take advantage of this.

[Daniel]

17 minutes ago, CanadaAmanda said:

@Daniel in your unfiltered tanks - do you have an airstone?  I have a 2.5 gallon that has an internal filter but low surface agitation... it's fantastic for floating plants but I'm starting to see a film on top of the water.  I do water changes on it 2-3 times a week anyway, but I hear it reduces gas exchange and I wonder how you get around that film in a tank without any filter/airstone/agitation?

I see that film sometimes, but I don't worry about it.

In the biggest tank (the one whose underside is pictured above) without a filter or airstone, I have a pump that moves the water in a big circle (the inlet and outlets are hidden by the driftwood) which gives plenty of flow and a little surface agitation.

In smaller tanks without a filter or airstone I keep plenty of plants. And some of those aquariums have plants sticking up and out the top of the water (I don't know this makes much of a difference). Whenever I have measured dissolved oxygen levels in this tank, they are always fine.

On top:

Through the side:

An airstone can be beneficial if you want to add extra fish to an aquarium. But if the aquarium is lightly stocked, the main benefit of the airstone is to circulate water around.

 

[CanadaAmanda]

@Daniel Oh very cool, is that the historically accurate 30's tank?  Looks like the green water subsided.  I have moneywort plants sticking out of my 2.5gallon, and there is enough agitation to allow the salivinia to spin around the surface (for 3-4 days until I need to yank more out to allow for more light and agitation) and there are other plants as well.  Thanks for that, I'll worry less for sure, especially with the plants growing as well as they are.  It's got 4 red cherry shrimp and 4 ember tetras so it seems moderately stocked and they are fed on the light side, however I do squash every baby snail I can easily reach so they get extra snacks. 🙂