Source of cloudiness in water

Hi All,

I'm struggling to figure out what could be causing some cloudiness in my 3 month old 200 litre community tank. I have no live plants in the tank, just rocks and driftwood with pool filter sand as substrate. Running an Oase Biomaster 250 filter.

When I dose Seachem Clarity my water becomes crystal clear...then a day later you can already see some cloudiness appear again

Water parameters seem very good (zero nitrites, nitrates or ammonia). I'm pretty sure it's not from over feeding or over crowding and there is never any detritus visible in the tank...the tank and substrate appear to be very clean (apart from some green spots on the wood here and there). I do a water change of at least 30% weekly and have only ever used RO /DI water in the tank.

Any tips on how I can determine what the source of the cloudiness could be?

Thanks
Chris

 

I would think if the tank is cycled you should be seeing some nitrates? Also what do you re-mineralise the RO/DI water with?

 

Hello ccronje
Welcome to the forum.
It is very unusual to have zero nitrates with a water change of around 30% . With around 24 fish in 200 litres you should be seeing nitrates of some amount?

I also wonder if the tank has a working nitrogen cycle?

 

Thank you for the comments so far. The tank definitely has a working nitrogen cycle, it took about 4 weeks for all the stages of the cycle to complete at first. I use Seachem Replenish and Alkaline buffer to recondition RO/DI water. If there is a small amount of Nitrates present, it doesn't seem to show on the API test that I have.

 

Ok that’s good news, the tank has good bacteria.

Do you have the paper ammonia test as well ?

Would you describe the cloudy water as coloured white or green?

Is there sunlight from a window hitting the tank?

 

Flyfisha Thanks again for helping.

There is no sunlight anywhere near the tank. To me the cloudiness looks white like a bacterial bloom, here is a photo of what it looked like from the side of the tank at the worst time before I started using Clarity. Ammonia shows 0 on the test that I have.

I have Purigen in my filter, not sure if that perhaps could be making things appear different to what they really are.

I thought if it was a bacterial bloom it would go away after a few days, but after about 10 days it didn't seem to improve, which is when I decided to try Clarity.

The last photo is what it looks like today after using Clarity

 

It does seem like that’s a bacteria bloom because of the colour and not getting to much sunlight.

However the only other thing I can see that I wonder about are the rocks and sand.

I have no experience with pool filter sand except to say the pool filter sand sold by “ Clark rubber” in my town NSW Australia is not suitable for aquariums . I know it’s often written about as being suitable in the US .


As for the rocks I am no expert on them at all . Just wondering what the PH difference is in the tank compared to tap water that’s been sitting overnight?

If you have not tested your tap water after it’s been in a glass jar for 24 hours that’s something to consider. If there is a difference in PH between that water and the tank water ( before a water change) we might have something to go on ?

 

Flyfisha I only use RO/DI water in the tank and use Seachem Replenish + Alkaline Buffer to treat the RO water...not sure if I perhaps am doing something wrong there?

I am not sure about the sand and rocks either...the water was clear for a few months before it started doing this, so this leads me to think that it's not the sand at least.

 

OH yeah you did say it was RO water.

Looking back at post #4 the paper test seems to show a reasonable GH and PH .?

 

It's difficult to know what is triggering the bloom. The bacteria are obviously having a party feeding on something. Perhaps you could try switching to a different GH booster. It's interesting to me that in my time on the forum it seems that these blooms disproportionately occur in tanks that utilise RO water. Or perhaps it's my imagination?

Anyway 3 months is a relatively new tank and the cloudiness is likely to abate as the tank and filter mature further. On that front it wouldn't hurt to add some extra filtration. Probably not what you want to hear but that filter has a manufacturer stated flow rate of 900 L/H. In practice it's more likely to be around 600 L/H which is only 3 times tank turnover per hour.

 

GlennO thank you for the comments. If the consensus is that it is likely a bacterial bloom then at least I have a starting point. You are right about the flow rate on the Oase filter, I did a flow test on it a while back with all filter media in place and it was closer to 500L/H. I added a small powerhead to increase water movement, but was never sure if this would be enough filtration for the tank. It does seem to do a good job based on how clean the tank looks (apart from the cloudy water of course), but perhaps not.

Maybe I should consider changing to tap water as well, I guess it is a process of elimination.

 

Is your tap water suitable? Why is it that you are using RO water?

 

Is your tap water suitable? Why is it that you are using RO water?

I'm not quite sure to be honest, but I think it should be ok. I just figured it would be best to start from a clean base with water that contains absolutely nothing that could be unwelcome in an aquarium, since I have a dedicated RO/DI unit I can use for it.

 

#1 the "bloom" is mild. Most of that I see in the video is blur which is caused by a film being laid down on the glass. I think you have LED lights? They will make diatoms look "white" vs. "Brown" like below, just flourescent tank lights, vs. Led camera flash.



I had a similar thing happen on this tank, i dont have any live plants either. mind you my bloom is quite severe. But what's been happening for the last 3 weeks now is the diatoms are consuming the nitrates, the tank is 10ppm nitrates for 3 weeks without water changing and with this many adult angels it should be putting on around 100 nitrates a week, and it was before this bloom. Why they are consuming nitrates, I have no idea. There's really nothing else for them to consume, but they appeared when nitrites appeared, cleared those out, then transitioned to the nitrates.

I'm honestly also not sure how I end it. I can clear it up some with an 80% water change for like a week or two but it comes back to this after the 2nd week. Clarifier helps minimally for like a day and not a solution. This blooms been going for 3 months.

It's not "pretty" of course, but its not going to hurt the fish and its keeping my nitrates minimal. I'm hoping at this point it populates to a point it using current nitrates and will run zero and then the bloom starves off, but with my fish producing 10-15ppm nitrates a day I'm not sure that's ever gonna happen.

I think your tank is doing the same thing, it's diatoms and they've adapted to consuming nitrates for energy. In theory doing nothing and riding it out for a month or so they should deplete either their food (nitrates or phosphates) or silica for their shell hardness, become weak and die off and settle into the background in low numbers in the substrate and then go clear. Mines taking a lot longer to get there due to my overstocking.

Diatoms get lumped in with true algae because they are very similar. They both need light to grow, they eat organic wastes like nitrates (NO3-) and phosphates (PO4) out of the water column. Once that gets depleted they depopulate. If they don't have silacates for their shell hardness, they get weak and die off also, like snails without calcium.
The theory is to do nothing, no water changes, just clean the glass and the worst eye sores that really bother you and let it run its course not adding new nutrients and it will balance off when they deplete it and balance occurs.
The thing is it's really hard not to change water when the tank looks this bad and you can't see the fish. They reproduce every 15 minutes, you won't water change them away, I've been trying.

 

GlennO thank you for the comments. If the consensus is that it is likely a bacterial bloom then at least I have a starting point. You are right about the flow rate on the Oase filter, I did a flow test on it a while back with all filter media in place and it was closer to 500L/H. I added a small powerhead to increase water movement, but was never sure if this would be enough filtration for the tank. It does seem to do a good job based on how clean the tank looks (apart from the cloudy water of course), but perhaps not.

Maybe I should consider changing to tap water as well, I guess it is a process of elimination.

GlennO just wanted to give you some feedback. After much consideration I added a second canister filter to the tank and within days the water became clear...when I switched on the 2nd filter the additional water movement stirred up a lot of detritus that must have been lying amongst the rocks and the water looked dirty for a while, but then it cleared up quickly after that. The new filter has a UV light, but I'm not sure if that made a difference.

 

GlennO just wanted to give you some feedback. After much consideration I added a second canister filter to the tank and within days the water became clear...when I switched on the 2nd filter the additional water movement stirred up a lot of detritus that must have been lying amongst the rocks and the water looked dirty for a while, but then it cleared up quickly after that. The new filter has a UV light, but I'm not sure if that made a difference.

Just wanted to update on my bloom, it's almost over now. Slight haze. Just did nothing except clean the glass and flat surfaces as it all died off and settled. I think in your case the UV did make the difference on your mild bloom though that and the extra filtration.