Issue With Weird And Persistent Foamy Surface (help)

Daniel Himawan
  • #1
Dear Fish & Tank Expert.

Tank Detail :
Tank Size : 52 Gallon
Filtration : Jebo 828 Canister 1200L/H and UGF 700 L/H
Media filter : sponge, bio crystall, ceramic ring, purigen
Ammonia : 0
Nitrite : 0
Nitrate : 20-30
i'm using tetra & apI test kit
tank age : around 1.5 month
display of my tank :

I have this weird persistent foam on the surface of my aquarium it seems that the surface tention is so high that avoid the bubble from bursting immediately, to help the analysis process I will share a couple of evidence :

1. when I put my hand inside the water or when I feed my fish with mizuho high growth the surface tension suddenly lowered and the bubble gone for a while, but after 10-20 minute the bubble/foam is coming back

2. I took a bucket of the aquarium water and put an aerator inside the bucket and leave it for a couple of hour, the bubble/foam is still exist after a while.

3. if I took my well water and put an aerator inside it there's no bubble / foam.

4. 2 days a go I put 0.05% salt into my aquarium (my aquarium is foamy but not that much only 25% area covered at first but after the sand putting process the foam is almost 100%), yesterday because of the existance of the bubble/foam I do 70% water change (and I don't put more salt because usually I will top up my salt every time I do water change), but the bubble / foam is still there I really don't understand what causing this

5. I have surface skimmer but it seems it doesn't help at all

6. my well water have high nitrate around 5-15 ppm (will this causing algae growth?)

7. I feed my fish twice a day with no more than 2-3 minute feeding time, I feed them hikarI lion head, mizuho high growth, algae wafer, lettuce, frozen peas.

8. I only turn on my LED 8-10 hours a day.

my questions are :
1. is it possible the surface tension is caused by algae blooming? there are some algae in my aquarium but not that much as you can see my glass is crystal clear I found a little algae staying on my aquarium dop rubber and in the areator tube, previously this thing happened and I do canister tube cleaning and found lots of white algae inside the tube after the cleaning the bubble is better, but this time the algae is minor i'm not sure if the algae causing the surface tension.

2. is it possible that the protein residue from my sinking pellets is sucked by the undergravel filter and remain inside of my sand and affecting the chemical inside my aquarium? I siphoned regularly so far I have yet leave my aquarium for more than 4 days without water change and siphoning.
is it really because of my sand? (i'm using volcanic sand which is common here in indonesia to use this type of sand as gravel) I don't have this foamy problem for the first 3 weeks of my tank, I realize the problem after I put 0.1 % salt for the first time, i've tried to put salt into my well water but the foam/bubble doesn't appear.

3. is it possible that the combination between salt and algae causing this?

4. will UV sterilizer solve my issue?

5. is there anything else I should try to get rid of this bubble?

I Really feel frustrated.. I know my tank is a bit overcrowded, but they are small in size, i've seen lots of other tank double my number with the same tank size but have no issue with bubble.


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  • #2
Adding salt can possibly enhance bubble formation. Protein skimmers are more effective in salt water for this reason.

Dirty water is also foamy. What's your water change schedule like?

The fact that your source water doesn't foam indicates that something is being added to the water. It could be a chemical or simply fish waste.

In my tank, foamy, smelly, or cloudy water means my filter isn't working well or I need to do a water change.

I don't think a UV sterilizer will help.

Daniel Himawan
  • Thread Starter
  • #3
thank you for replying,

my tank is not smelly (no smell at all) or even cloudy, the water is crystal clear enough.

regarding fish waste, is it means that may be my canister can't handle the tank? or the canister need to be cleaned? can you inform me how to identify this? I mean when I open my canister usually its quite clean even in the foam media, its only a little brownish and blackish.

even after 70% water change the bubble / foam is still appearing after a couple hour.

my water change schedule so far is once every 3 days.. last time is around 36 hour ago 70% WC.

is it possible that I need to reduce my feeding rate?

how often do I need to clean my canister? I expect once every 1 month or 2 months....
Daniel Himawan
  • Thread Starter
  • #4
anyone would like to chip in ?
  • #5
The only time ive seen a tank foam like that is when useing melafix its a tea tree extract .in the picture you posted of the foam on top I noticed a plant appears to be hanging down into the tank. I wonder if it could be leeching some type of oil into your water causeing the same affect as melafix .just a thought.
Daniel Himawan
  • Thread Starter
  • #6
i'm thinkin the same too, its a pothos plant / devil's ivy, I saw a lot of people using it with no harm... but the variable is still vary and right now I only can guess...
  • #7
When you do your water change turn the filter and any other thing you have running off, let the tank set for a few minutes, suck the thin top surface layer off. If you look at the surface from an angle you should be able to see the oily slick, suck it all off.
Daniel Himawan
  • Thread Starter
  • #8

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