# Diatoms Enigma



## cyhiemstra (3 Aug 2013)

Hey all

I’m here for round 3 now.  Been through quite the learning curve and im still not there.  I get to points where I think I am but keep being proved wrong, so I need help (again)..

Tank data:
30L Nano
11W light / 9hr
Plants: Myriophyllum Mattogrossense and Eleocharis Acicularis
Dosing: EI (@6ml per day)
CO2: yeast setup + 2ml easycarbo daily (2x1ml per 12h) 
Im doing weekly 50% water changes


I have some other posts with some very helpful responses and advice which I followed, but the diatoms are persisting, which indicates some imbalance not simply resolved. The theory I was going on was lack of CO2, and too much light. All of which ive fixed.

Also worth noting that all my previous observing browning plants were actually very healthy plants underneath once the brown layer was wiped off.  

To attempt to resolve the diatom explosion I went heavy on the co2, from 1ml to 1.5ml to 2ml a day while running and replacing the yeast system. Also got couple of oto’s which did a great job cleaning around the tank.  And the diatoms kept blooming.

 About 2 weeks ago when it was getting very bad, I decided on a rigorous tank clean.  I cleared the tank of all diatom-covered half decaying HC - a load of debris was causing a total mess entangled in the hairgrass. I threw all the HC out, I removed all the hairgrass, did a methodical cleaning by hand and planted the hairgrass back in, spread out.  I siphoned the gravel, cleaned the filter, removed most old filter floss but added ceramic rings and left some of the floss in.  It looked great, and I felt that with a consistent yellowgreen dropchecker plus the 2ml (.6ml a day recommended on the bottle) easycarbo, the diatoms were now completely cleared and wouldn’t come back.  

Two days later it came back.  I kept a close eye, and noted there was none on the rock but it was beginning to take over the hair grass once again.  A week later and it did start on the rock and the glass too.

It has been a little over a week of it getting worse and ive gone ahead and done another fliter+gravel wipint plants etc clean again, while I scratch my head..

Ive had a couple of theories bouncing around now:

1/the tank hasn’t completed cycling (tank commenced end may so 2 months)
2/substrate disturbance caused mini cycle
3/substrate is just dirty
4/filter is just dirty
5/not enough plants to compete with diatoms
6/not enough plants for amount of nutrients in the tank!
7/general nutrient overdose
8/lack of flow/spread (i have tried everything for this so very unlikely)
9/still not enough co2 (also highly unlikely)

Again- plants are super healthy once the brown sludge is wiped off them.

My main theory is the nutrients overdose causing a buildup in the tank, if I fill the tank with plants it may just throw the whole thing into balance.  In the meantime I will do smaller more frequent water changes.

All ideas welcome!


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## tim (3 Aug 2013)

Your list should contain too much light 9 hours is a long photoperiod mate most folks using t5s use 6-8 hours.


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## cyhiemstra (3 Aug 2013)

Aah seriously? I thought that but still read about 8-10 hr being normal.. 

It's a bit of a shame with the 11w growth is incredibly slow


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## tim (3 Aug 2013)

Faster growth will require more maintenance maybe keep it as it is, and clean/ water change two to three times weekly if possible. I find nanos quite demanding in the maintenance department.


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## cyhiemstra (3 Aug 2013)

There must be a reason why they keep returning. Deinfitely going to continue with a rigorous maintenance plan but still keen to find what the imbalance is


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## sa80mark (3 Aug 2013)

Id definitely look at the lighting and co2,  I have the same size tank and similar set up I only run 7 hours lighy and use pressurised co2, yeast co2 can work but doe fluctuate alot which wont help with any algae,

Also one thing that stands out is you haven't mentioned what filter your using, if this is on the weak side flow could be a route cause


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## cyhiemstra (3 Aug 2013)

Indeed, I'm following your tank, done great 

My filter is the standard dennerle nano eckfilter. It does provide quite a bit of flow as I've taken the standard infill module out and just filled the container with ceramic rings broken into pieces with filter floss on top of that. With regard to flow, the filter sits in the corner with spray bar along the glass, my danios float in place in the current alongside the opposite face, so I think it's reasonable.  I would consider a replacement but I'd have to convince SO too, with potential for something small like the 501 or HOB.. Thoughts welcome!


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## sa80mark (3 Aug 2013)

I would definitely recommend an external filter the 501 is imo underpowered rated at 200lph id  look for something like an eheim 2213 or similar

The eheim 2213 can be picked up on Amazon for around £30 and is a real bargain you wouldnt regret

I would 100% say your problems are flow and fluctuations in co2


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## sciencefiction (4 Aug 2013)

From my point of view, diatoms are caused by mini ammonia spikes, possibly undetectable on a test in most scenarios. Obviously they need light too, but light just controls how fast they grow. They also seem to have harder time attaching with more flow but I hardly doubt it that will stop them if the first two factors are present.

Once a tank matures, plants and filters outcompete the diatoms for ammonia, but in early stages none could be growing/mutliplying fast enough to do so, hence diatoms in new tanks is common. Obviously, for that reason you should do everything possible for your plants like CO2/nutritients/distribution/light combo to make them grow well, but how well they'll manage the ammonia produced in a new tank also depends on the type of plants, amount of plants, etc.. So you should address the filter as well as your next best friend. In your case, no matter what others may think, I'd suggest you stop washing that filter for a month If it's just 2 months old, the bacteria colony is hardly established and not so well attached to the media yet and by washing the filter, you are removing the bits that have multiplied and would otherwise have helped to outcompete the diatoms for ammonia. In a normally stocked tank it will hardly even have any "dirt" in it even if left uncleaned for longer periods of time. The other thing that maybe important at this stage is oxygen. A new tank may need lots of oxygen to establish well all important aerobic bacteria that consumes ammonia so for now you may look into increasing the surface agitation as long as it doesn't interfere with your CO2. Your plant mass may not be enough, or healthy enough to produce enough O2 at this stage.

Having a bigger capacity for media/higher flow filter will help in any case as long as you don't bin the old media in the process. And I'd stop disturbing the substrate because that certainly won't help. Also, maybe see if you can feed the fish less as that could be another cause but even if it is, it's mostly because your tank has not established yet properly.


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## cyhiemstra (4 Aug 2013)

Sciencefiction thanks for the in depth reply. I'm going to diagram it up so I understand it a bit better but if you're saying the bacteria is one of the components that offer competition against the diatoms then indeed I've probably blundered.. My paranoia got the best of me when reading about "clean tanks"  and in cleaning gravel and filter have probably like you say been removing this beneficial bacteria. Knowing that oxygen is necessary for developing the bacteria is good to know. 

Additionally I also suspect I do not have enough leaf surface area to help the tank as a whole. Having removed the hc, the thin strands of the hairgrass and the very lanky myriophyllum aren't exactly a mass of green compared to the size of tank, small as it may be. 

On the other note fish food shouldn't be a problem, being so overly paranoid I'm very careful with how much I feed them. 

Back to the filter and two big concerns/queries I still have- which would help me leave the thing alone even if I replace it:

1/Do the diatoms not fill up the surface area of the rings making it hard for bacteria to colonise them(in current setup where there is very little foam)? Or does this space actually have too much flow for them to attach? 
2/is the point of replacing filter floss to keep permeability, not necessarily to collect and remove junk from the tank? It was going diatom-brown in a matter of days and having this great want to remove everything diatom I went ahead and changed it. 

Many thanks


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## sciencefiction (4 Aug 2013)

> 1/Do the diatoms not fill up the surface area of the rings making it hard for bacteria to colonise them(in current setup where there is very little foam)? Or does this space actually have too much flow for them to attach?
> 2/is the point of replacing filter floss to keep permeability, not necessarily to collect and remove junk from the tank? It was going diatom-brown in a matter of days and having this great want to remove everything diatom I went ahead and changed it.


 
1)The diatoms shouldn't be populating your filter because they need light to survive. However, if when you clean diatoms you leave most of it floating in the water, then some may end up there. I normally use paper towels making sure none ends up floating in the water. I know it's hard, because it's like dust but that's the only way. Or at least do large water changes before turning the filter back on. Otherwise there's no point cleaning diatoms because they just re-attach.
2)Are you sure it's diatoms inside the filter? A well established filter will become brown. That's the normal colour.
Floss is to be exchanged from time to time, but for now that's against your interests. Removing the floss removes the bacteria too because some ends up there too. As I said above, if I were you for the time being I'd leave that filter alone unless your filter cloggs or something but that would be due to wrong maintenance, and even then you can just give it a wash in tank water instead of replacing.


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## ceg4048 (6 Aug 2013)

The OP has too much light. Reduce the lighting and the diatoms will go away.

Cheers,


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