# Algae outbreak following CO2 upgrade.



## aledr2004 (10 Feb 2011)

Hi all.

I'm running a 90L with 2x 24w T5's and a Fluval 105 external filter. I've used Aquasoil amazonia substrate and it's quite densely planted with Hairgrass, Bacopa Australis, a stem plant I forget the name of, and Xmas and weeping moss. 

I haven't been dosing any macro ferts as it's quite densely stocked, just TPN for traces at 5ml per week. My tank has been running for about 5 months now and I have had great success with excellent growth and very little algae at all. 

2 weeks ago I upgraded to pressurised CO2 from DIY as I was sick of changing the bottles and assumed that more CO2 = better growth and less algae. Since then I have had a huge outbreak of green hair algae which has swamped my mosses completely. Plant growth seems unchanged. What could be the reason for this? I struggle to understand the ferts side of things to be honest but I'm guessing a defficiency must be the cause? Should I start dosing TPN+ for more Macros?

Any advice would be greatly appreciated.


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## chilled84 (10 Feb 2011)

you need more flow! More nutrients! More water changes on a regular basis. Steady co2 levels from lights on to lights off. Aim for 10 times turnover rule. 90l tank 900ltr an hour.


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## ceg4048 (10 Feb 2011)

aledr2004 said:
			
		

> ...2 weeks ago I upgraded to pressurised CO2 from DIY as I was sick of changing the bottles and assumed that more CO2 = better growth and less algae. Since then I have had a huge outbreak of green hair algae which has swamped my mosses completely. Plant growth seems unchanged. What could be the reason for this? I struggle to understand the ferts side of things to be honest but I'm guessing a defficiency must be the cause? Should I start dosing TPN+ for more Macros


Hello,
  Your assumption that more CO2 = better growth is correct. However, filamentous algae is always a result of poor CO2 uptake. Therefore, assuming that the lighting and flow rate stayed the same, it must be concluded that even though you upgraded to a pressurized distribution method, the amount of CO2 being injected must somehow be lower than what you had with the previous DIY installation.

I'd suggest for starters that you check for external leaks, ensure that your filter flow rates are up to par, ensure that your dropchecker is filled with 4dkh water, and that the gas is turned on at least an hour or so prior to lights on. After these are checked then it's a simple matter to slowly increase the injection rate being careful not to gas your fish.

Cheers,


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## foxfish (10 Feb 2011)

If you are confused with ferts then perhaps you could try this all in one mix, even if it is only while you get you head around it all http://www.aquariumplantfood.co.uk/cate ... ategory=25.
This might not be the absolute cheapest way to go but, it certainly works for me...


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## nry (10 Feb 2011)

As above - the CO2 has increased the uptake of nutrients to levels way beyond what he fish stock would have produced which was sufficient pre-CO2.


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## aledr2004 (10 Feb 2011)

Thanks for the responses!



> you need more flow! More nutrients! More water changes on a regular basis. Steady co2 levels from lights on to lights off. Aim for 10 times turnover rule. 90l tank 900ltr an hour.



Ok, but I'm on a pretty tight budget at the mo so a bigger filter is out the question. Any suggestions for a cheap way to introduce more flow? 



> Your assumption that more CO2 = better growth is correct. However, filamentous algae is always a result of poor CO2 uptake. Therefore, assuming that the lighting and flow rate stayed the same, it must be concluded that even though you upgraded to a pressurized distribution method, the amount of CO2 being injected must somehow be lower than what you had with the previous DIY installation.
> 
> I'd suggest for starters that you check for external leaks, ensure that your filter flow rates are up to par, ensure that your dropchecker is filled with 4dkh water, and that the gas is turned on at least an hour or so prior to lights on. After these are checked then it's a simple matter to slowly increase the injection rate being careful not to gas your fish.



Thanks Ceg. Whilst I bow to your expertise, it cannot be the case that CO2 uptake is less. Previously using DIY I was probably achieving on average 0.5 bubbles per sec resulting in a thin trickle of micro bubbles into the filter intake, which would reduce significantly as the bottles needed changing. Now I have 3 bubbles per sec and a good steady stream coming from the diffuser, again into the filter intake. There are definitely no external leaks either. However I'm waiting for my drop checker off ebay so I've just adjusted the CO2 by trial and error, initially my fish were gasping at the surface and I gradually reduced the CO2 until they appeared comfortable.



> As above - the CO2 has increased the uptake of nutrients to levels way beyond what he fish stock would have produced which was sufficient pre-CO2.



OK, so I need to up the nutrients, but what I can't get my head around is if the demand for nutrients is outstripping supply, surely there is less for the algae to use. How does a lack of nutrients benefit the algae?

Many thanks everyone. This site is a fantastic resource to have.


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## foxfish (10 Feb 2011)

From reading you reply  I would say, you need to distribute the gas around the tank.
You don't need a new filter just some more water movement via a power head.
Also (sorry if I missed this) what sort of diffuser are you using?


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## CeeJay (10 Feb 2011)

Hi aledr2004


			
				aledr2004 said:
			
		

> OK, so I need to up the nutrients, but what I can't get my head around is if the demand for nutrients is outstripping supply, surely there is less for the algae to use.


This will never be the case. Your plants maybe outstripping supply to sustain their own health, but algae can survive on far less nutrients than a plant. Once you've triggered it, it will then feed on the same nutrients that you feed your plants.


			
				aledr2004 said:
			
		

> How does a lack of nutrients benefit the algae?



In a nutshell
Lack of nutrients = poor plant health. 
Poor plant health = Ammonia being released from the dead or dying leaves. 
Ammonia and light = algae...............everytime


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