Strange Bad Smell, cloudy and low ph in 3 month old 5 gal tank

  1. pagnardc Initiate Member

    I have a 5 gal tank with 5 small guppies and a snail in it. It is a 5 gal marineland nook with built in filter. I started the tank 3 months ago with 3 red minor tetras. Everything went well, for about a month. I cycled the tank and ammonia wer really healthy looking all was fine. I then developed a strange film on top of the water, the tetras we gulping for air at the top of the tank. I realized my filter had been aimed down at the bottom of the tank and not disturbing the surface, which i believe in turn allowed the bacteria to grow on surface and would not allow any oxygen into the tank. I took the fish out for a day and did a water change and adjusted the outflow for the filter. Tank cleared right up, put the fish back in and tank was great for about a month. The tank was a present for my daughter who decided she would like cobra guppies instead of the tetras. I took the tetras out and put the guppies in. All was well for about 3 days. Now my ph had dropped down to below 6. All other levels are good, including ammonia. I bought some ph balance stuff (proper ph 7.0 by API) to help raise it to 7. The water is now very cloudy and smells really bad. Not decay, but a funky cleaner like smell. The ph is still down below 6 and water still cloudy after a week. Fish seem to be doing well. Please help!View attachment IMG_20160619_151301877.jpg
  2. aliray Fishlore VIP Member

    Hi and welcome to the forum. Glad you decided to join us. Does the filter have activate charcoal in it as part of the filter? That would help with the smell and might help with the cloudness but only works for a month and then you need to put fresh charcoal in. What are the current water parameters? Ammonia , nitrites and nitrates? Alison:;hi1

  3. oldsalt777 Well Known Member Member


    The smell is dissolved waste. It's building up and my guess is, if you removed some into a white bucket, it would be yellow. That's dissolved waste from the fish. There's no place for the waste to go, so it builds up. In a small tank, the waste builds up quickly and will kill off your fish.

    The tank is too small to support a fish of any kind. Get a larger tank. At least 30 gallons or plan on going to the fish store to get more fish.

  4. pagnardc Initiate Member

    oldsalt, I don't think that response was very helpful. I have been doing water changes regularly, and my other levels are fine. I have not notices the water being yellow. I understand the tank is small. I have heard from numerous people with the same size tank and they have no problem with healthy fish. I have also had the aquarium up and running for 3 months with no issue in terms of fish waste. Other thank just telling me to get a bigger tank, i would appreciate any help.

  5. superbutterfly12 Well Known Member Member

    I would guess its a component of the ph balancer the filter isn't getting or bacterial bloom from the increase in bioload that will clear up in a week or two.
  6. pagnardc Initiate Member


    The tank had a small charcoal filter that I replaces with a pouch of seachem Purigen. The water was crystal clear a day after the change, that was about 3-4 weeks ago. I have been testing the levels. Here is what I have. Ammonia - 0-0.2ppm, Nitrate - 0, Nitrite - 0, Hardness - 150, Chlorine - 0, Alkalinity - 0, PH - 5.6-58. I am new to community fish. I have had african cichlids for more than 12 years and never ever had anything like this. I will say, with my africans, the tanks were always much bigger with better filters. I had to get rid of my big tanks a few years ago, had a canister filter malfunction and it dumped water all over new hard wood floors...Wife said that was it for a while. I wanted to get a small tank for my daughter and this was recommended...I know it is really small, but we only wanted to have a couple fish and see how she did with it. Plus, it was the right size for my wife. Spilling 5 gallons is a lot less than 55 or more. Any help would be appreciated. Thanks!


    Thanks superbutterfly12, I'll keep monitoring it and see how it goes. Should i do more frequent water changes thank once a week? or let it go and monitor it? Thanks.

  7. oldsalt777 Well Known Member Member

    Hello again pag...

    The post was very helpful. You're a beginning water keeper and need to know that the water in small tanks changes almost hourly from even a small amount of waste from your fish. Small tanks don't have enough water in them to dilute the waste from even a few small fish. This is exactly why the water smells.

    Tanks take many months of work from you to become livable for the fish. Tanks take several weeks just to cycle. Getting involved in the water keeping hobby takes a long term commitment, years not a few months, if you want to succeed and telling someone their tank is doing fine when it very likely isn't, isn't helping the water keeper learn anything about the hobby.

    Apologies if you're offended, but a small tank isn't the place to start.


  8. pagnardc Initiate Member


    I'm not offended. I had african tanks for more than 12 years, I'm not new to aquariums, just new to small community tanks. I appreciate your honesty and knowledge in this situation. I have, however put some money into this small setup and would like to try all options before throwing away my money. Also, for many people buying a 30 gal aquarium isn't an option (whether no room or something else). I appreciate that you seem like you know are knowledgable in aquariums, and i would appreciate any help. I'm obviously not looking for someone to say the tank is fine, i wouldnt be here. I'm also not looknig for someone to say "just give up". I don't see a lot of help in your post. Agan, Im not offended, and I hope that I have not offended you. Thank you
  9. Silister Trench Well Known Member Member

    Although, maybe not worded to your liking, oldsalt isn't wrong.

    My guess is two factors that are contributing to your problem. The first, as oldsalt said, is your tank is too small for what you currently stock. 5 gallon tanks make good Betta tanks, good shrimp or even snail tanks, and if planted heavily can support a larger bioload, but 5 guppies is probably a lot for your set up and tanks like this often just become reoccurring problems.

    The second is too little filtration to meet the needs of the fish. According to your first message ammonia and everything should be at 0, right? What test kit are you exactly using because the haze in your water looks like a bacterial bloom often seen during cycling periods, or on the chance you caused a mini cycle usually by cleaning filters or removing media. With this haze it's usually accompanied by a spike in ammonia, but if your test is accurate, then perhaps the biological filtration has sufficient filter flow, but the mechanical filtration does not. Again... That doesn't seem likely because your PH has dropped.

    Who feeds the fish? What? And how much? And is this person 100% that no one else comes along an or or two later and feeds them again?

    What filtration system is does that have and does it seem to be functioning normally?
  10. pagnardc Initiate Member

    Silister, I'm using the API Ammonia test kit (not strips). The filter on the tank is built in, and I'm not sure its great...although it was filtering out fine with the 3 larger tetras I had in there. I feed the fish exclusively now. My wife was helping and i think over feeding, but that was weeks ago that i had her stop. I have been cleaning out the gravel during water changes. Have not had a lot of waste or uneaten food sucked up by siphon vacuum. I make sure only to give them small amounts of food once a day.I did a 40% water change 2 days ago, and a 30% change yesterday in the hopes that it would help with the smell and no avail.


  11. Silister Trench Well Known Member Member

    Okay, we can assume your test kit is accurate then. I tried looking online for information on this filter, but all it tells me is something along the lines of "three-stage biological built-in filtration" which doesn't provide anything useful.

    If your wife was over feeding (more than likely, I'd imagine, because mine dumps a tablespoon of flakes in for 17 neons whenever she got a chance. ) then excess food built up in the substrate and filter could have spiked ammonia. Enough for a bacterial bloom in the water column? I don't know... Maybe? If it did water changes won't fix it. Bacterial blooms have to take their course.

    Couple other questions while I'm racking my brain because none of this solves the PH drop. Have you checked and cleaned this filtration system lately. I assume it's "3-stage filtration" was activated carbon at one point or media balls of sort, a course black pad and a polishing pad? If they've been cleaned recently that could be your cloudy water. If not, make sure the polishing pad isn't saturated in filth and nothing as accumulated anywhere else including the impeller or water pump - whatever it uses to move water.

    And then, have you tested your water straight out of the tap lately? If you're on a well, sometimes shifts in the ground can cause drastic water changes. Even city water is prone to change. I know mine has .25 ammonia out of the tap with a PH of 8.0. If I leave it out over night the ammonia remains the same but PH drops to 7.0. In tank it stays at about 7.4. Just some examples on maybe what to look at.

    Is this smell a as you described before, or is there a fishy rot to it?

    EDIT: And do you by chance know thekH of your water? A higher kH provides more stable pH in your water, and a lower kH can be the cause of pH swings.
  12. pagnardc Initiate Member

    The filter is not fantastic. at the back of the tank there is a separate section which houses the "filter" There is a small charcoal pouch on top of a course black sponge. the water passes through that to the back section and there is a small pump at the bottom that pumps the water back out to the tank. I think it is a pretty terrible filter, but nothing else will fit back there. I have attached a picture. It doesnt smell like rotting...its really unique and i cant place it. In all the years of african tanks i never had this smell before. ThanksView attachment IMG_20160619_175456576.jpg
  13. MikeRad89 Well Known Member Member

    The tank is not cycling because of the low pH. Raise the pH with crushed coral and your BB colony will be able to handle the waste.

    Uncycled tanks stink because the waste isn't being broken down.
  14. Silister Trench Well Known Member Member

    I just thought of that same thing. Haha!

    The bacterial bloom is caused by your low PH. BB prefers 7.0 to 8.0 I believe and if your pH is below six your ammonia ionizes and becomes ammonium. Basically your low PH is starving your biological filter causing a cycle.
  15. pagnardc Initiate Member

    Thank you Mike and Silister. I'll get some crushed coral tomorrow and give that a try. Thanks all, including Oldsalt.

  16. MikeRad89 Well Known Member Member

    Not a problem. Once your pH starts to get around 6.5 you're going to see some stress from your fish.

    As silister said, at your low pH ammonia becomes ammonium which is far less toxic to fish. The low pH is why they're alive even in the absence of a cycle. When you grab the crushed coral grab some seachem prime and dose daily once your pH reaches 6.5 or so, or when you start to see symptoms of stress.

    Best of luck.
  17. superbutterfly12 Well Known Member Member

    Your purifen may need to be replaced or recharged if it's been there 3 or 4 weeks. Check for discoloration. It gets used up. Great stuff though!