Help! Looks like Black mold invading my tank!

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weelz6699

Aquarium Advice Newbie
Joined
May 17, 2009
Messages
6
I have a 125 gal. setup. Am running two HOT Pro canister filters w/Bio-wheel filters. No under gravel filter. Have pea sized gravel substrait. Recenty switched from a discus to an angelfish populatiom. 9 quarter sized angeles,8 dwarf gourami, 4 med. Bala sharks, and 3 african breed catfish (brown w/white spots) I had an old peice of driftwood but replaced it with a new smaller peice when this first happened. I change out my plastic plants for live when I made the switch. I have 3 med. swordleaf and 4 java fern plants some petrafied wood and slate rock to build caves.

Well a blackish looking mold or algae started forming all over everything ecsept the fish. I did a full clean scrubbing all the rocks, vacuming all gravel, wipintg down all sides of glass, and cleaning the filters. All was well for a few days till the black stuff started coming back. This is not BBA it is very short like common green algae

Please help if you can!
Thank,
Tom
 
First thing people are going to want to know...
how often do you change your water/ and how much
water paramiters.. ammonia/nitrates/nitrites.
And the question i like to ask.. can you just give us a picture lol
 
I change about 30 percent every 2 weeks and my water tests all in mormal levels.
 
what are you using to test strips or a liquid test kit. It would be a lot of help if you can tell us
1. what your parameters are
2. how long has your tank be up
And if you could post a pic it would help a lot
 
If it is a slimy sheet that is stuck fast to the surface & smells funny (or gross!), it is Blue green algae (BGA), aka cyanobacteria. Some species are brown, red or black .... hence they are also called red slime algae.

This is nasty stuff to get rid of. Because BGA can fix nitrogen, nutrient restriction is not effective. It is sensitive to high oxygen levels, so the first thing to do is to increase water flow & O2 content ... perhaps an airstone & a powerhead. You can kill the stuff by increasing O2 artificially with H2O2 <caution, reports of fish & plant deaths doing this!>, or adding the "loading dose" of Excel for 5 days. However, unless the condition that promotes BGA is corrected, killing it is just a temporary solution.

Other ways to combat this si maintaining a good/constant nitrate level (5-10), & stable CO2 level if injecting CO2. This is to allow the other plants (& green algae) to out-compete the BGA as nitrogen fixing is less efficient.

Finally, a blackout can kill BGA, but in my experiments, it took over 1 week to kill the stuff. A 48 hr blackout simply did nothing.
 
tests

what are you using to test strips or a liquid test kit. It would be a lot of help if you can tell us
1. what your parameters are
2. how long has your tank be up
And if you could post a pic it would help a lot


I am using a liquid tst kit and my results show:
ph=7.0
Amonnia= 0-.5
Nitrite=0ppm
Nitrate=5.0ppm

Tank has been upabout 5 yrs.
 
This sounds more like it!

If it is a slimy sheet that is stuck fast to the surface & smells funny (or gross!), it is Blue green algae (BGA), aka cyanobacteria. Some species are brown, red or black .... hence they are also called red slime algae.

This is nasty stuff to get rid of. Because BGA can fix nitrogen, nutrient restriction is not effective. It is sensitive to high oxygen levels, so the first thing to do is to increase water flow & O2 content ... perhaps an airstone & a powerhead. You can kill the stuff by increasing O2 artificially with H2O2 <caution, reports of fish & plant deaths doing this!>, or adding the "loading dose" of Excel for 5 days. However, unless the condition that promotes BGA is corrected, killing it is just a temporary solution.

Other ways to combat this si maintaining a good/constant nitrate level (5-10), & stable CO2 level if injecting CO2. This is to allow the other plants (& green algae) to out-compete the BGA as nitrogen fixing is less efficient.

Finally, a blackout can kill BGA, but in my experiments, it took over 1 week to kill the stuff. A 48 hr blackout simply did nothing.


I am running a bubble wall so my o2 should be well off but I am not runnimg any kind of co2 system. What would be good for a 125 gallon setup?
 
Whats the source of the ammonia spike? Any new members added? Any dead bodies rotting away? I'd say something is off if you are getting a .5ppm ammonia reading. I would do a water change to see if you can get it below .25ppm and then figure out whats causing it. In a 5 year old tank you shouldn't be seeing any ammonia.
 
I think ammonia is ok level

Whats the source of the ammonia spike? Any new members added? Any dead bodies rotting away? I'd say something is off if you are getting a .5ppm ammonia reading. I would do a water change to see if you can get it below .25ppm and then figure out whats causing it. In a 5 year old tank you shouldn't be seeing any ammonia.


That's not a spike my color card on my test kit says 0 to .5 when comparing test vial to a color chart.
 
Well may not be a spike per se, but regardless of what you want to call it... You shouldn't be getting any ammonia in a tank of that age. Any new additions, missing fish/deaths? Change filter media/gravel vac recently? I'm just trying to figure out what it could be.
 
A heavily planted tank shouldn't show any ammonia ... the plants will take it up. Maybe do the test with pure water for a comparison. I find those colour card hard to read .... an actual sample in the tube will show what zero looks like.
 
I am running a bubble wall so my o2 should be well off but I am not runnimg any kind of co2 system. What would be good for a 125 gallon setup?

The bubble wall will aerate the water where it is. In a big tank, there might still be dead spots of low water circulation. This is where BGA tends to collect (if that is what you have.)

For a 125 gal, you need pressurized system if using CO2. I wouldn't start on that just for the algae ... at least until you have things figured out. <The CO2 comment was more for the DIY CO2 systems. The fluctuating CO2 levels can bring on algae.>
 
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