Aquarium filtration for 20 gallon freshwater

Discussion in 'Freshwater Beginners' started by TK Titanium, Jun 21, 2016.

  1. TK Titanium

    TK TitaniumNew MemberMember


    I have a Top Fin 20 gallon freshwater aquarium which came with it's own HOB filter and heater. It has been running for over a month and is now fully cycled and, so far, I have added 4 Zebra Danios and 10 Neon Tetras, there are no live plants. One of the Danios is a bit of a bully and has claimed the top half of the tank for himself but, other than that, the fish seem happy. I'm here because I have heard many disparaging remarks about charcoal filters (like what the tank came with) and have been trying to see if I could set up something better. The filter came with what it called a "Bio Plate," I'm guessing it is meant to be a home for the nitrifying bacteria but I can't seem to find any information about it so I'll leave it in but I don't really trust it that much. So I thought that I would like to add some Seachem matrix bio media to the filter with the charcoal and slowly phase out the charcoal so the bacteria has time to colonize the new media. At the same time, I assume this means I need to add some mechanical filtration media to the area in front of the charcoal bag. My research suggests that I should add filter sponges but, as I tried to research these sponges, I got seriously overwhelmed and started to wonder if I was, perhaps, overdoing the whole thing. So, what kind of filtration do you think I should have for this tank (keeping in mind that I am on a very tight budget)? This top fin HOB filter doesn't have a ton of space so every piece counts.



    (p.s. This is my tank)

  2. peregrine

    peregrineValued MemberMember

    Activated charcoal isn't necessarily bad. What it does is remove chemicals from the water, and some claim ((I know my cartridges with it appear to)) keep your water cleaner. basically Bacteria lives on EVEYRTHING. The filter is just the highest concentration for it due to water movement. Yes the bioplate is meant to hold a good portion of the bacteria. I don't know how much room is in it, but basically you have to look at where the water flows in, make sure the sponge is between that and the bio media so it dons't get clogged up with gunk. With a water flow of 130 GPH it's actually kinda low for a 20 gal tank. But with the stock you have in it ((even adding up to the 5-6 total danios)) it should be fine. Really filtration requirements are on bioload of fish, not the size of tank ((for the most part..))

    I also want to comment on the danio. You really should have them in a 5+ school of fish. That could be why the one is being so aggressive. It's stressed not having a school.
  3. el337

    el337Fishlore LegendMember

    Once you modify the filter media by adding to it, you would have an even lower flow rate than 130 gph which is still under the bare minimum of 8x the filtration for your tank size.

    You may want to consider upgrading to a filter that generates 200 gph that has a large customizable media basket like an Aquaclear 50.

  4. peregrine

    peregrineValued MemberMember

    Agree with el337 doing that would also allow you to run both filters at the same time for a few weeks so the bacteria can build up on your new filter, so you don't have to recycle.
  5. OP
    TK Titanium

    TK TitaniumNew MemberMember

    Okay, thank you for the replies, they do bring up some new questions and I hope you will indulge me. I heard that the rule of thumb was 5 to 10 complete turnovers per hour so I thought I was well within that range. With 50, I would be concerned about the level of current for my little tetras, is that valid or am I underestimating them? With the set of media I have in my cart for Amazon (I was checking prices and seeing what is out there before getting overwhelmed), I could drop it all and add just ten dollars more for an AquaClear 30 for a mid-road 7.5 turnovers per hour. Though either way, I have to admit, I do have a bit of a hard time with the idea of retiring a brand-new, perfectly functional unit unless there is adequate cause. If anyone can present documented evidence for "adequate cause," I find that sort of thing very persuasive and would be grateful for the ability to move with certainty.

    Also, regarding the Danios. They are a bit of a thorn in my side and I honestly don't know what to do about them. I bought them to help with the cycling process because they are supposed to be sturdy enough to handle it but the more I learned about cycling the more I felt bad for them so I bought some API quick start to jump start things and make life easier for them. It worked and they are happy and active... a little too active... I was hoping for a bit of a calmer tank. I've learned that I don't really like Danios, so I would prefer not to have more but I also understand that as they slowly live to death and the population goes down, things will get even worse. I only have the one tank so I don't have any idea what to do with them. Suggestions are welcome there.

    Wow, that was long, sorry. Also, I hope it didn't sound combative, that is not my intention, I'm just a person with a lot of questions.
  6. peregrine

    peregrineValued MemberMember

    Everyone is here to help, ask all the questions you want, I didn't take it as combative.

    As for why go with a higher filtration throughput, really comes to how clean it can keep the water. Think of it this way If you have a filter that says every time water passes through it, it is able to clean out Say 1 Part per million of something. ((these are all hypothetical numbers mind you)) and whatever you have in the water produces 0.25 part per million per hour, if it turns it over 6 times, doesn't matter because you are filtering more than you need and it will clean it out fairly fast. Now you up that to 1PPM per hour produced with the same flow rate in the filter. that something stays in the water longer and if you filtration is static but you keep going up in what is putting stuff in, soon you will overwhelm the filtration.

    Now in practicality, with the fish you currently have in there your filtration is plenty. Without knowing your hopeful final stock it's hard to say if it's worth it or not. Filtration really comes down to more of what your bioload is and less ((to a point)) about the tank size.

    As for what to do with the danios, you might be able to find a nice home with someone close. Or sometimes LFS if you just say you are looking for a new home for them might take them.

    EDIT: you think that's long, go look at my intro on the welcome to the forums last week

    EDIT2: Another thing is a great site to find out stocking level and filtration is   they take into account bio load and for the most part are good about when you tell it fish only for my tank most are right, a few are a little off...
  7. el337

    el337Fishlore LegendMember

    Recommended filtration for HOB filters is 8-10x so again, you are underfiltered with the TopFin unless you are going to keep the tank lightly stocked then maybe you can just get by with just that filter alone and modify it a bit.

    You can keep the TopFin and add an AC20 for a total of 230 gph if you want to go that route of having two filters which is never a bad idea if one fails. The other great thing about AquaClears is that it has a knob that you can adjust to control the flow so your fish don't get blown around but with the AC50 alone, it should be fine for your tank. Many people on the forum have them on their 20g's.

    And is this a 20 high or 20 long? If you don't want the danios, I'd just rehome them now. You already have a lot of fish in there to be doing a fish-in cycle anyway.

    Also, do you own a test kit? How are your parameters looking?
  8. OP
    TK Titanium

    TK TitaniumNew MemberMember

    Thank you for the extra information. I'll have to make a decision sometime soon regarding the filter.

    Regarding final stock, I haven't decided yet. I don't think I have that much room left to work with. It would be nice to have a little cleaning crew (mainly because most of them have really interesting shapes) but cories wouldn't like my big rock substrate, shrimp may get eaten by my Danios, plecos are too big, snails like to escape, and otos like to be in bigger groups than I have room for. It would also be nice to get one or more middle/top swimmers depending on how much room I have left, maybe a Dwarf Gourami in that role.

    As for a test kit, I have a freshwater master kit. I do a 30% water change weekly, the results from right before my last change were: Ph:7.6 Ammonia: 0-ish (If it's not 0, it's darn close), Nitrite: 0, Nitrate: ~7.5
  9. peregrine

    peregrineValued MemberMember

    Danios wont eat the shrimp. I have a ghost shrimp in my tank and have some danios. And amano shrimp are fun to watch and pretty good little cleaners.

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