Bba and co2

**Htomassini** · 10-23-2010, 12:58 PM

Everyone always referS to the major source of brush algae as fluctuating co2 levels and or lack of circulation. But I have a question though. Isn't the process of turning off the co2 at night along with aeration hence raising the ph at night to start the co2 cycle again a fluctuation in itself?

Even though I start co2 2 hours before the lights come one it takes almost all day for my drop checker to turn light green.

I have a high light tank with sump setup so I degass the co2 at night quite efficiently. Plus I run and airstone in the sump when the lights are off

I am now running into brush algae and I want to control it before it gets out of hand

Thanks

**agentkhiem** · 10-23-2010, 03:29 PM

I was wondering about the same thing. What is considered CO2 fluctuation?

**dutchy** · 10-23-2010, 04:13 PM

CO2 fluctuation arises when the CO2 level falls so much that a temporarily deficiency occurs. This occurs during the photoperiod, not at night. It seems like the germination signal for BBA is low/fluctuating/falling CO2 levels accompanied by light. My CO2 is off at night but I don't have BBA.

A drop checker always has a delay, 2 to 3 hours minimum. On the other hand it could be a sign of slow response in your CO2 system. This could be as simple as bubble rate but also water flow through the reactor/diffusor. If you have a CO2 system with low capacity, CO2 could fall since the system can't keep up with the demand. If you're not able to reach the desired pH in one hour, you have a slow responsive system.

You could also think about lowering your light. Less light = less CO2 demand = easier to do = less algae.

regards,
dutchy

**Htomassini** · 10-23-2010, 05:08 PM

Well I have raised my lights nice and high with only one bank of 4 by 80w hot5. It runs from 11 to 9. Co2 starts at 9 am and that's when the airstone cuts off.

**dutchy** · 10-23-2010, 06:17 PM

Maybe your CO2 system is slow and unresponsive.

I have two CO2 systems on my 180 gallon, two 450 GPH pumps drive two AM1000 reactors. I can get to the desired CO2 level within 45 minutes. Yet both (pH controlled) systems are working hard the first hours after the light switches on. No BBA here.
Just giving you and example what could be required on a big tank.

regards,
dutchy

**Htomassini** · 10-23-2010, 08:36 PM

Hmm. I have an aquarium plants ext5000 reactor connected to a mag5 pump feeding to my mag 1200 in the sump

They claim this is the most efficient co reactor.

**dutchy** · 10-23-2010, 08:51 PM

Still there is probably some lag in the system, since your drop checker needs all day to get the right colour. Can you measure the pH difference in the morning and evening? This will at least tell if you there's a real difference. Maybe just the bubble rate is too low?

Also check if you're not outgassing a lot of CO2 through your sump. Gerryd can help you here.

Never assume your CO2 (or system) is ok. If it was, you shouldn't have BBA.

regards,
dutchy

**Htomassini** · 10-23-2010, 10:22 PM

As far as ph I can drop it .75 to 1 point (from low 7s to low 6s) in about under 2 hrS.
I started increasing the run time of 2 coralias from 15min on 30off to 30on 15off cycle. As far as degassing it drains to a sock no trickle filter. So I don't have a lot of surface agitation.

**Gerryd** · 10-23-2010, 11:54 PM

Henry,

Will you be around tomorrow? I can come down and get the mag 350 for sale and check out your setup at the same time...

Let me know. Will call later, as I have your #.

Thanks