# Algae apeared in hi-tech tank - reason?



## Arryl (20 Apr 2009)

Hello. I have 17 litres tank:

1,2 watt per litre light 10 hours
CO2 - from CO2 tank 24\7 diffused via small pump impeller to micro bubble condition.
External filtration
PH - 5,9-6,0
KH-2 GH 4
Tank is densely planted with HC, R.spGreen. L.arquata, R.fluitans. E.parvula ÐµtÑ.
Daily dosing NPK +trace+Fe (all DIY)
NPK dosing (weekly concentration) - No3 - 18ppm PO4 1,2 K-26,4.
Fe 0,1 per day
Water change - 70% weekly.
After change I add 20ppm of K, 0,2 0f Fe and double day dose of NPK.
Everything was fine since start in Jan09.
But at last week on second day after WC I found small green hairs (probably Oedogonium or fuzz algae) on arcuata leaves, then on the next day on the H.microntemoides and on E.tennelis rubra. I start nervous cause everything was stable. I check No3 level with Tetra test and find 3-5 ppm max (but I add such amount dayly with double dose after wc). Fe level was also checked - 0,5ppm.
So on next day i change 50% of water and add 6ppm of no3 ant night and 6ppm at today's morning. At evening I check level - aprox 7 ppm - so i decide to add another 10 ppm of no3 (i have separate solution) to give plant no limitation in no3. Did I made correct?

But the main question for me is - what the reason of the algae activation?

My assumption:

1. Im check ph level - and was surprised - may be because of some problems with my co2 system - but ph was 5,56 (its in evening time) (instead of 5,9-6,0). So may be this cause CO2 increasing which stimulate NO3 consumption, its drop to low level and algae activate? - but to do this plants must stop its grows.? isnt it? Or even low concentration of NO3 is enough?
2. May be HC start grows faster and start eat all nutrition which cause level drop.
3?? dont know.. seating here and nervous - cause it tank for exhibition and
not that presaged trouble.

So I dont want to add some chemistry and do not want to make blackout or something like this, cause it cant affect plant its stop growing and......oh my god.
Please any advise and assumption will be very helpful

Algae photos











Tank photo


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## Ed Seeley (20 Apr 2009)

You are trying to measure ferts with test kits which are not really accurate enough to do this reliably.  Just look at the tutorial on EI and then add the amounts of ferts your plants need and don't worry about measuring them.

However you don't seem to be measuring your CO2 which is vital!  Use a drop checker with 4dKH water (another article on this is in the tutorials section) in it will ensure you have 30ppm CO2.  This and adding the right amount of ferts (rather than chasing ppm with test kits) should see of any algae.


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## Arryl (20 Apr 2009)

Ed Seeley said:
			
		

> You are trying to measure ferts with test kits which are not really accurate enough to do this reliably.  Just look at the tutorial on EI and then add the amounts of ferts your plants need and don't worry about measuring them.
> 
> However you don't seem to be measuring your CO2 which is vital!  Use a drop checker with 4dKH water (another article on this is in the tutorials section) in it will ensure you have 30ppm CO2.  This and adding the right amount of ferts (rather than chasing ppm with test kits) should see of any algae.



Actually its not a new tank.. Tank was started at Jan 2009. And everything was ok. Same Light CO2 and Dosing.
Of courser test a lies. But I now how much NO3 a add daily (4 ppm) So i can approx estimate how much its remains after WC at the end of the week. 
CO2  -I have DC its always yellow.


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## Ed Seeley (20 Apr 2009)

What about the circulation?  Have you tried positioning the DC in different places to check that you're CO2 and ferts are distributed all around the tank?


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## Arryl (20 Apr 2009)

Yep. DC green everywhere. Actually its only 17liters tank - and pump have productively aprox 120 liter per hour. I think quite enough. The main strange is that from Jan 2009 everything was ok. And after one WC its begins. (I change RO and reconstructed water)


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## Ed Seeley (20 Apr 2009)

Being set up only since January means it isn't that old and established yet so a few teething troubles are not totally unepxected, so don't panic.

I noticed from another post of yours that you use a pH controller.  Is that on this tank?  If so this could be the source of your issues.  pH controllers work by turning CO2 on and off to manipulate the pH.  What you want in a planted tank is stable CO2 - it doesn't matter what the pH is.  What you want is the bubble rate controlling the amount of CO2 being added so it is consistent during the hours when the lights are on.  If you want to keep using the pH controller then set it to cut off the CO2 if it climbs above 30ppm which will cause the pH to drops lower than this.


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## Arryl (20 Apr 2009)

No. in this tank my CO2 is open 24-7. Co2 going to pump impeller and broke to micro bubbles.
So due to its continuously opened  I have some Ph fluctuations 6.3 at evening and 5,7 at morning.
I also think that i made big WC - 70% its too much for such small size...isnt it?
Actually i have no Flourish Excell which many uses to algae fighting but i have Cidex. its glutare aldegide. So may be try it to help plants?


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## Ed Seeley (20 Apr 2009)

The water change shouldn't have really caused issues.  I don't know that product you mentioned but if it's the same as Excel you can use it to kill off the algae.  I still think it's a CO2/circulation issue at the end of the day though!


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## ceg4048 (20 Apr 2009)

Looks like it could be Oedogonium, which could easily be a combination of low CO2 and nutrients or, if the DC is always yellow, then it might be flow related. As the tank grows in there is more plant mass and less flow gets to each plant, so more of everything needs to be added. Don't compare the tank in January to the tank in April, it's really a different tank because of the higher mass as well as other things.

That's a very pretty tank though!  

Cheers,


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## baron von bubba (24 May 2009)

probably a stupid question but, after a W/C do you give it a chance to get the co2 levels back up before lights on?


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