Need help setting up my first 20 gal long - need filtering and levelling advice

[JamesRush93]

Hello! I’m helping my girlfriend start a 20 gallon long tank and had some questions about set-up - mainly around sponge filtration and levelling. She is upgrading from a 5 gallon planted tank with a betta, two mystery snails and shrimp. The plan is to bring all of those into the new tank along with a school of rummynose tetras, a shoal of pygmy corys and a pleco. The new tank will also be planted.

First question about the initial setup.. the surface the tank is on is not 100% plane which I’ve read is important. There is a tiny gap in one area between the bottom frame of the tank and the surface. It’s basically no larger than a 1/16th, I can only see it because of a sliver of light shining through it. Here’s a photo to illustrate what I mean:



Should I buy a foam mat to place under the tank or is that only necessary for rimless tanks? Is there nothing to worry about with a gap this size? Also, we filled the tank to test for leaks and noticed the water level has a 1/4 inch difference between the two front corners of the tank. Is this significant enough to be of concern? The level of the stand itself cannot be changed as it is part of a long wall unit which is screwed into the wall.

Next is the filtration. We’ve been running a small sponge filter in the 5 gal with the betta which has worked great since they don’t like a strong water flow. We bought a large corner-shaped sponge filter for the 20 which is apparently good for up to 40 gallons to do the same. Might have gone overboard it is quite large:


Is there such thing as getting one too large? Will one of these be enough to filter the entire tank with the stock I mentioned above? I’ve read people suggest powerheads for longer tanks but am unsure how those work or how necessary they are. Do I need one of those? Keep in mind that I’m trying to avoid heavy water flow for the betta. But maybe the school of tetras would benefit from something like that? Also the fact that the tank will be planted should help with filtration in its own way

I am pretty confident by now in setting up smaller tanks - I have my own 5 gallon planted tank and helped set up my girlfriend’s as well - but I’m not sure if everything I know can scale up to the footprint of a 20 gal long. Any advice you have is much appreciated, thanks!

Edit: On second thought now I do think the sponge I got is too big... the tube the bubbles come out of is going to be sticking out of the tank once the substrate is in:



Would something like this be sufficient on its own:

Powkoo Aquarium Fish Tank Filter Sponge Filter Double Sponge Filters with 2 Media Containers (Black) Powkoo Aquarium Fish Tank Filter Sponge Filter Double Sponge Filters with 2 Media Containers (Black): Amazon.ca: Pet Supplies

 

[ForceTen]

Hello! I’m helping my girlfriend start a 20 gallon long tank and had some questions about set-up - mainly around sponge filtration and levelling. She is upgrading from a 5 gallon planted tank with a betta, two mystery snails and shrimp. The plan is to bring all of those into the new tank along with a school of rummynose tetras, a shoal of pygmy corys and a pleco. The new tank will also be planted.

First question about the initial setup.. the surface the tank is on is not 100% plane which I’ve read is important. There is a tiny gap in one area between the bottom frame of the tank and the surface. It’s basically no larger than a 1/16th, I can only see it because of a sliver of light shining through it. Here’s a photo to illustrate what I mean:

View attachment 770397

Should I buy a foam mat to place under the tank or is that only necessary for rimless tanks? Is there nothing to worry about with a gap this size? Also, we filled the tank to test for leaks and noticed the water level has a 1/4 inch difference between the two front corners of the tank. Is this significant enough to be of concern? The level of the stand itself cannot be changed as it is part of a long wall unit which is screwed into the wall.

Next is the filtration. We’ve been running a small sponge filter in the 5 gal with the betta which has worked great since they don’t like a strong water flow. We bought a large corner-shaped sponge filter for the 20 which is apparently good for up to 40 gallons to do the same. Might have gone overboard it is quite large:

View attachment 770401
Is there such thing as getting one too large? Will one of these be enough to filter the entire tank with the stock I mentioned above? I’ve read people suggest powerheads for longer tanks but am unsure how those work or how necessary they are. Do I need one of those? Keep in mind that I’m trying to avoid heavy water flow for the betta. But maybe the school of tetras would benefit from something like that? Also the fact that the tank will be planted should help with filtration in its own way

I am pretty confident by now in setting up smaller tanks - I have my own 5 gallon planted tank and helped set up my girlfriend’s as well - but I’m not sure if everything I know can scale up to the footprint of a 20 gal long. Any advice you have is much appreciated, thanks!

I will address your leveling and your concern with the small gap between the tank bottom and the surface it sits on.
You must level the stand. Do not attempt to level the tank on the stand. So this means you need to level the surface you will place the tank on.
Personally I would use a tank stand designed for the purpose as they have leveling legs that are super easy to use.
Do you have carpet or a hard surface floor? If its carpet, you will need to level it as you ad water.
So check it as you fill it. Keep checking it.
The Gap!
This gap is completely normal with a commercial tank stand. Its hard to say with what you are going to use as a stand. There are other threads on this and you should search and find them. However once again I am in the minority. I trust the manufacturers recommendation over what is talked about here.
I was told by Aqeon and Imagitarium that there should not be anything between the tank and the stand respectively.
That the corners should not have a gap, but the rest of the tank bottom can and do have a gap the thickness of a credit card.
They told me not to use the insulation board I had purchased for this. This gap was gone once the tank was filled. 2 years now and no issue.

I would highly recommend an Aqua Clear HOB. The AC 50 is recommended. Its rated for much more than 20 gallons but for me I would probably go with the AC 70.

 

[TucanSam]

Hello! I’m helping my girlfriend start a 20 gallon long tank and had some questions about set-up - mainly around sponge filtration and levelling. She is upgrading from a 5 gallon planted tank with a betta, two mystery snails and shrimp. The plan is to bring all of those into the new tank along with a school of rummynose tetras, a shoal of pygmy corys and a pleco. The new tank will also be planted.

First question about the initial setup.. the surface the tank is on is not 100% plane which I’ve read is important. There is a tiny gap in one area between the bottom frame of the tank and the surface. It’s basically no larger than a 1/16th, I can only see it because of a sliver of light shining through it. Here’s a photo to illustrate what I mean:

View attachment 770397

Should I buy a foam mat to place under the tank or is that only necessary for rimless tanks? Is there nothing to worry about with a gap this size? Also, we filled the tank to test for leaks and noticed the water level has a 1/4 inch difference between the two front corners of the tank. Is this significant enough to be of concern? The level of the stand itself cannot be changed as it is part of a long wall unit which is screwed into the wall.

I would probably place down a yoga mat to make up for that gap. It shouldn't cause too much issue, but its better safe than sorry. It seems like there isn't too much you can do about leveling the tank, but I don't see this as too much of an issue. Several of my tanks aren't perfectly level despite my best efforts (including a 125 gallon). If my physics are still right, water puts out even pressure in all directions, so if it is going to really cause damage, it would have to be so out of level that water is spilling out of one side. I think by that point you'd have bigger immediate issues than a possible crack.

Next is the filtration. We’ve been running a small sponge filter in the 5 gal with the betta which has worked great since they don’t like a strong water flow. We bought a large corner-shaped sponge filter for the 20 which is apparently good for up to 40 gallons to do the same. Might have gone overboard it is quite large:

View attachment 770401
Is there such thing as getting one too large? Will one of these be enough to filter the entire tank with the stock I mentioned above? I’ve read people suggest powerheads for longer tanks but am unsure how those work or how necessary they are. Do I need one of those? Keep in mind that I’m trying to avoid heavy water flow for the betta. But maybe the school of tetras would benefit from something like that? Also the fact that the tank will be planted should help with filtration in its own way

I am pretty confident by now in setting up smaller tanks - I have my own 5 gallon planted tank and helped set up my girlfriend’s as well - but I’m not sure if everything I know can scale up to the footprint of a 20 gal long. Any advice you have is much appreciated, thanks!

There's no such thing as a filter too large... unless you get one too big. With sponge filters you don't really have the problem with strong currents or water flow you would have with large HOB or canisters. Theres no reason not to have a big one except for space concerns. A 20 long shouldn't need to worry about water flow or circulation much.

Edit: On second thought now I do think the sponge I got is too big... the tube the bubbles come out of is going to be sticking out of the tank once the substrate is in:

View attachment 770434

Can you just bury the base into the substrate? Or cut the tube down a bit? I'd hate for you to just throw away money on it, even if it is cheap.

Would something like this be sufficient on its own:

Powkoo Aquarium Fish Tank Filter Sponge Filter Double Sponge Filters with 2 Media Containers (Black) Powkoo Aquarium Fish Tank Filter Sponge Filter Double Sponge Filters with 2 Media Containers (Black): Amazon.ca: Pet Supplies

 

[JamesRush93]

Thanks for the filter recommendations ForceTen, I’ll look into those but was hoping to stick to a sponge filter. Would you say a sponge filter alone is not enough for a 20 long? Good to know about the gap it really is a tiny gap not even half the width of a credit card. I’ll forget about that. As for the levelling, It really can’t be changed on this piece of furniture as it’s a shelf of a sturdy wall unit which is screwed into the wall. What could potentially go wrong in a tank my size if it’s 1/4 inch out of level? Seems like it’s pretty split wherever I look including this thread if it’s something to worry about or not or if it’s a cause for concern in a larger tank?

Thanks for the input TucanSam, I was able to return the big filter for free to Amazon and order the other one. Even if that filter was buried in the substrate the water level would have to be almost brimmed to the top to keep the output pipe submerged. Would rather buy a more reasonable sized one than cut it down. So you’re saying not to worry about getting a powerhead? Think that other sponge filter I linked from Amazon will be enough on its own?

 

[ForceTen]

Thanks for the filter recommendations ForceTen, I’ll look into those but was hoping to stick to a sponge filter. Would you say a sponge filter alone is not enough for a 20 long? Good to know about the gap it really is a tiny gap not even half the width of a credit card. I’ll forget about that. As for the levelling, It really can’t be changed on this piece of furniture as it’s a shelf of a sturdy wall unit which is screwed into the wall. What could potentially go wrong in a tank my size if it’s 1/4 inch out of level? Seems like it’s pretty split wherever I look including this thread if it’s something to worry about or not or if it’s a cause for concern in a larger tank?

I would think a sponge filter on your size tank would be somewhat inefficient as far as flow and turn over. I have not used them so I cannot be sure?
1/4" out of level would drive me nuts. I am a perfectionist and could not live with it.
Its not a mechanical issue, its a personal issue for me. If you can live with 1/4" un-level so be it. Good luck.

 

[TucanSam]

I don't have much experience with sponge filters, so I'd have to do some research to know for sure.

I probably wouldn't worrying about a powerhead. If your concern is flow about the betta to the point you're going sponge filter, then a powerhead completely contradicts that anyway.

If you're going for a hob, you can always put sponge in the outlet to more evenly distribute the flow.

 

[NotSoAggressiveAquatics]

Sorry I can’t help about the filter and stuff but I wanted to add that your stocking will be ok if you don’t add the pleco. Even smaller species need a tank of 30 gallons minimum to live a good life. And watch out for fin nipping on the betta from the tetras

 

[ProudPapa]

• As long as the stand is level, and all four corners of the tank are supported (no gaps there), it should be fine without a mat, but of course it can't hurt anything.
• I have a reasonably heavily stocked 20 long with an AquaClear 20 with an intake sponge, and a moderate sized sponge filter. If I was doing it again I would bump up the size on the AC, since I frequently need to remove the intake sponge to clean it. Other than that, it seems to be fine.
• I agree with AggressiveAquatics about skipping the pleco, but as long as you have a decent-sized school of the tetras I don't think you'll have any issue with fin nipping.

 

[JamesRush93]

Sorry I can’t help about the filter and stuff but I wanted to add that your stocking will be ok if you don’t add the pleco. Even smaller species need a tank of 30 gallons minimum to live a good life. And watch out for fin nipping on the betta from the tetras

I agree with AggressiveAquatics about skipping the pleco, but as long as you have a decent-sized school of the tetras I don't think you'll have any issue with fin nipping.

Thanks we’ll definitely research plecos some more before considering them for this tank. Is the minimum size of 30 the only reason they wouldn’t work? We were thinking a bristlenose or a clown.

What would constitute a decent sized school of rummynose for a 20 long? We were thinking 12 but now I’m wondering if we should do more? Would 15-20 be too many? If so, the stock would look like: a betta, two mystery snails, 10-12 Pygmy corys, 15-20 rummynose tetras. Is that reasonable or does that need some adjusting?

 

[jake37]

As others said it is critical that the stand be level and all four corners are firmly resting. I use a paper test for my tanks (not just corners but full tank). The reason this is critical is you can get a stress fracture when you fill the tank (basically the area not on the surface will be forced down by the weight of the water and this can cause the glass to crack which leads to a wet mess. You could put a piece of ply wood under the tank since it appears that the top is warped. Can't comment on foam.
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As for the sponge filter - the quality/density of the sponge and uplift are more important than the actual size. I'd go for 20ppi sponge or 30ppi if you cant' find 20ppi. Also you can 'cycle' the tank by putting the new sponge filter in the 5 (leave the current filter) and run it for a month before you setup the 20 or conversely move the old filter to the new tank when you set it up. You still might get a slight spike in ammonia (0.5ppm or 0.75ppm) but it should stablize pretty quickly.
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For your stocking a decent sponge filter is fine. The sponge filter you showed in your picture from a size perspective is a bit on the large size for your needs - bigger doesn't hurt but a smaller one would be fine as long as the sponge and uplift are decent.
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A clown pleco would fit fine - a bn pleco - depends a bit on the size as an adult - i really wouldn't put a 6 inch pleco in a 20 long - but if you get a female that stays closer to 4 inch (not all females stay smaller) you would be fine. If you get a bn i'd go for starlight, lemon blue-eye or super red.
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For the tetra - i'd limit the size to 8 initially and see how it goes - a 20 long is pretty shallow and depending on how you plant/landscape it there might not be a huge amount of room - also the pygmy cory - if they are comfortable - like to swim mid level and will compete with the tetra for space.
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This is a 20 long i had a while go (first is setup; 2nd is near tear down):

 

[ProudPapa]

What would constitute a decent sized school of rummynose for a 20 long? We were thinking 12 but now I’m wondering if we should do more? Would 15-20 be too many? If so, the stock would look like: a betta, two mystery snails, 10-12 Pygmy corys, 15-20 rummynose tetras. Is that reasonable or does that need some adjusting?

I think that's going to be pretty heavy. I'd suggest starting with about 10 each of the pygmy corys and rummy noses. If all is going well, and your numbers are doing good, you might consider adding a few more later.

 

[JamesRush93]

Thanks for the advice we’ll start with a smaller stock. Nice tank Jake, did you have a pure sand substrate or was it layered with soil underneath to help the plants? We’re doing sand but are concerned about how well plants can grow in it vs soil but your plants clearly did very well.

 

[jake37]

Sorry was commenting on wrong tank - let me repost:

The substrate is moonlight (caribsea). It does have some negatives in that it will compress and cause some pockets so it does need to be stir a bit. Also it is very very light and easily gets swirled into the water. I think i would go with crystal river (slight coarser substrate) if i were to do it over. Still if you are going to have live plants you should have 2 to 3 inches of substrate (i lean towards deeper is better).

Thanks for the advice we’ll start with a smaller stock. Nice tank Jake, did you have a pure sand substrate or was it layered with soil underneath to help the plants? We’re doing sand but are concerned about how well plants can grow in it vs soil but your plants clearly did very well.