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Yellowish wisps of smoke in tank

1265 Views 13 Replies 3 Participants Last post by  mistergreen
Not sure if this is the right section for this question but for a week and a half I've had this cloudiness in the water column that looks like wisps of smoke, sometimes with yellowish tinge to it.

This is a Walstad setup that's been running for 8 months with no problems outside the initial phase.

This is how it looks in the evening before the lights go off:

This when the lights are off for the siesta period at noon (5on-4off-5on):

And this was today right after the lights came back on after the siesta:
This is the most concentrated I've seen it yet. Off course after the lights were on for a while it diffused throughout the water with more density in the upper layer.

NH4, NO3 and NO2 are all at 0, as always. Well, NO3 is normally at 1ppm but now at 0. Today I did a GH and KH test just in case and found out they are both at 6 instead of the usual 11. However, the last time I measured these was at least 3-4 months ago. Thus, no idea if this is a recent development.

Fish seem to be doing well. They're eating and look alright, for now at least.

Does anyone know what tis is? More importantly does anyone have any experience with how to deal with it or what could have caused it?
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It could be a bacterial or protozoan bloom. A water change should help.
I did one 50% water change on Monday. It was back within 24 hours. I could try once more but what would stop it from growing back again?
Oh, it could also be some critter moving the dirt particles into the water column.
No, it is definitely organic in origin, because it follows the light. What I tried to explain in the previous reply was that the bacteria or whatever it is repopulated to almost pre-water change concentrations (visually) basically over night.
Try 50mg/L of salt and do a water change a week later. That should hurt the organism. The dirt is leaching food for the organism. With enough water change, the food should reduce.
Won't the salt hurt the plants, substrate or shrimp too? Also keep in mind that this is a no filter setup. The only water movement is produced by the fish.
In case the salt is safe to use, how much should I use for 63 liter tank. By that I mean, considering the substrate is about 7cm thick and the tank is not filled up to the brim, should I go with a 50 liter equivalent(2.5g of salt)?
Too much salt can be bad for plants but 2.5g in 50L is fine.

Another option is 3% hydrogen peroxide. Dose no more than 1.5ml/Gallon.

Another option is biological. Small fish should eat those protozoans. Filter-feeding crustaceans should work too like daphnia.
I'll try the salt first then.

If that doesn't work I could try hydrogen peroxide. I'm a bit worried though that dumping 75ml of hydrogen peroxide into the tank that has no water movement would create areas that are very concentrated. Maybe I'm overthinking it a bit but I never used it on a tank with livestock in it. Will it be safe for the fish and shrimp?

Concerning the biological treatment, I have 11 chili rasboras and they don't touch it. Or maybe they prefer the dry food I give them once a day. Shrimp seem to eat it (or perhaps its product) during the afternoon siesta. With the lights off, the bacteria concentrate at the front of the tank near the substrate and every shrimp from the tank is there when I turn on the light. However, in almost two weeks, they didn't put any dent into it.
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Correction on the peroxide dose. It’s 1.5ml/ gallon. Or 1.5ml/ 3.7L

Oh, on the peroxide, do a water change after an hour of dosing. Peroxide is relatively safe in appropriate dose. It breaks down to water and oxygen.
Good to know. On that note, will a 50% water change be enough when using peroxide?
Correction on the peroxide dose. It's 1.5ml/ gallon. Or 1.5ml/ 3.7L

Oh, on the peroxide, do a water change after an hour of dosing. Peroxide is relatively safe in appropriate dose. It breaks down to water and oxygen.
Why do you need to change a water if it breaks to H2O and O2?
You don’t have to. It’s only preventative.
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