Good news..my cynobacteria has gone! Bad news.. diatom explosion instead.

[Cat]

Hello,

I posted about a cyno problem a couple of weeks ago. I made a few changes to my regime after advice I received. I stopped dosing ferts completely (I was E.I dosing) after suggestions that my Amano substrate would be adequate on its own for the time being. I've started doing two water changes a week in part to get more oxygen in the tank. I have a spray bar that runs the length of the tank, after the two changes I don't quite fill it to the top so I get more surface agitation at night, then top it up again before the CO2 comes on in the morning. I replaced my carbon filter as I realised that it would probably be defunct now anyway and topped up the fluidised bed as it had lost some of its sand and so was on the small side. I've been syphoning almost everyday to try and get the cyno out and then just in the last couple of days I noticed it has gone and has been completely replaced with what looks like light brown dusty stuff which I think fits the description of Diatoms. I'm not sure what this might indicate or what I should do now. I was wondering if there was any chance of it just working itself out? (long shot)

Just a few specs -

Homemade LED lights
Fire extinguisher CO2 with a inline ceramic diffuser with pale green in the drop checker
405 litre tank
Fluidized bed filter in general circulation, with a chloramine/chlorine, sediment and carbon canisters on the in pipe for water changes straight from mains.

I live in Cambridge the water is pretty hard Ph 8.2 going in with Ph 8.5 in the tank with a TDS of 194.
All the plants I have are in the easy category.

 

[Aqua360]

Hello,

I posted about a cyno problem a couple of weeks ago. I made a few changes to my regime after advice I received. I stopped dosing ferts completely (I was E.I dosing) after suggestions that my Amano substrate would be adequate on its own for the time being. I've started doing two water changes a week in part to get more oxygen in the tank. I have a spray bar that runs the length of the tank, after the two changes I don't quite fill it to the top so I get more surface agitation at night, then top it up again before the CO2 comes on in the morning. I replaced my carbon filter as I realised that it would probably be defunct now anyway and topped up the fluidised bed as it had lost some of its sand and so was on the small side. I've been syphoning almost everyday to try and get the cyno out and then just in the last couple of days I noticed it has gone and has been completely replaced with what looks like light brown dusty stuff which I think fits the description of Diatoms. I'm not sure what this might indicate or what I should do now. I was wondering if there was any chance of it just working itself out? (long shot)

Just a few specs -

Homemade LED lights
Fire extinguisher CO2 with a inline ceramic diffuser with pale green in the drop checker
405 litre tank
Fluidized bed filter in general circulation, with a chloramine/chlorine, sediment and carbon canisters on the in pipe for water changes straight from mains.

I live in Cambridge the water is pretty hard Ph 8.2 going in with Ph 8.5 in the tank with a TDS of 194.
All the plants I have are in the easy category.

Beautiful tank

 

[Cat]

Thank you! It was origonally for Discus fish hence the size. Dying to put fish in it but it's all Brown.

 

[sciencefiction]

was wondering if there was any chance of it just working itself out?

Yes, keep up what you've been doing and the diatoms phase will sort itself out as the tank stabilizes.
Diatoms are an indicator of excess ammonia being released which in turn is a good indicator that there's enough oxygen to break down the organics. Eventually everything will level itself out and the plants and filter will start coping. As for the current diatoms, it's all about water changes, cleaning up as much as possible and trimming severely affected leaves. It will run its course too eventually but can damage the plants a bit, not more than the cyano though. Otocinclus would be quite happy helping up with the clean up.
A possible third stage could be a bit of BBA if you are unlucky.

 

[Cat]

Yes, keep up what you've been doing and the diatoms phase will sort itself out as the tank stabilizes.
Diatoms are an indicator of excess ammonia being released which in turn is a good indicator that there's enough oxygen to break down the organics. Eventually everything will level itself out and the plants and filter will start coping. As for the current diatoms, it's all about water changes, cleaning up as much as possible and trimming severely affected leaves. It will run its course too eventually but can damage the plants a bit, not more than the cyano though. Otocinclus would be quite happy helping up with the clean up.
A possible third stage could be a bit of BBA if you are unlucky.

Thank you for your response!

Yes I think I killed my fluidised bed filter so it probably did have to start again, I'll have to put in a non-return valve because I keep accidentally syphoning the sand out. I have some really unhappy Alternanthera Rosafolia do you think I should just remove them? We turned the lights down to try and deter algae when we started the tank but its probably too low for them, I have some Cyperus which I only just discovered have a high light requirement also and they don't look marvellous either whereas everything else is fine. I turned the lights up (led's) yesterday because the tank has been going for a few months but maybe its still too soon even if these two species need it?

 

[sciencefiction]

Hey, I used to have a fluidised sand bed filter. It ended up in the bin. The valve will help to control the flow. Mine eventually developed a pin hole at the bottom and leaked 1/3 of the tank on the floor. It was difficult to keep the water pressure constant anyway, and it was driving me crazy for the year I had it, so no regrets.

It's up to you whether to remove the plants. I'd remove damaged leaves. If the light is not adequate for the plants, try more under supervision. The point is to give the plants the best chance to pick up even if the algae grows faster. The diatoms as I said are due to ammonia, not due to the level of light. Best is to sort out the filter or get a different one/second filter.

 

[Cat]

I'll keep the lights up then. I read somewhere ( probably on here ) that if you ran the tank with a lot of CO2 the plants developed around that amount, then plants that normally wouldn't need that much C02 end up needing more than they otherwise might of? If that makes any sense? Which is another reason I've kept the lights low.

I'm thinking of getting another filter anyway that could act as a mechanical filter as I have so much plant debris.

 

[sciencefiction]

The plants don't like a drop in CO2 so during transition they may suffer but they adjust back.
The relation between light and CO2 isn't that linear. There's scientific data that CO2 and light can compensate for one another and that relation is probably not unique to these two only.
So lower light means plants need higher CO2 and higher light can compensate for lower CO2. There's also an optimum level of light for different species of plants. Below that, they wither and die.
CO2 is more variable in tanks, it never runs out to a point to kill a plant because lots of natural processes in a tank produce CO2. Nutrient deficiency show up as such, e.g. yellowing leaves, chlorosis, stunted growth, etc...
The plants I've seen dying from too low light either stay the same size for months or their leaves turn brown and melt. I had an old thread somewhere showing the effect on several plants but can't find it right now. It was from a few years back.
The other option to test those plants whether light is the issue, is to move them to an area of the tank that is well lit.