# C02/02/surface agitation/flow questions in a new 20g Planted



## Charlie97L (Aug 14, 2007)

I recently moved my 8 gallon biocube into a 20 gallon to give everything more space. I have an eheim canister filter (2213 i think), and the red sea c02 system with regulator.

now, my question is... how do I balance c02 and 02? i'm going to run c02 during the day, and have it shut off at night... but do i need to be running an air pump, or something to oxygenate the water? Or will the canister filter also work.

also, what's the deal with surface agitation... i know too much will degas the c02, but not enough will leave a scummy water surface right? also, do i need powerheads, or will the canister return spraybar be enough.

i'm coming from a reef background, so i'm worried i'm going to end up with too much flow... i need some guidance! 

thanks!
charlie


----------



## houseofcards (Feb 16, 2005)

If you were running the co2 24/7 you might need an airstone or the ablity to agitate the water depending upon the co2 levels in the tank, but if your shutting off at night you shouldn't need anything.


----------



## Charlie97L (Aug 14, 2007)

ok, and with a planted tank, is there really a need for a surface skimmer or more flow than the canister will provide?

i'm used to reef tanks getting gross after like 5 mintues with no surface skimming, but as i said, this is new territory for me.

thanks!


----------



## houseofcards (Feb 16, 2005)

Charlie97L said:


> ok, and with a planted tank, is there really a need for a surface skimmer or more flow than the canister will provide?
> 
> i'm used to reef tanks getting gross after like 5 mintues with no surface skimming, but as i said, this is new territory for me.
> 
> thanks!


There are certainly people who use surface skimmers and people who use powerheads to increase flow, but I am not one of them. Of course every tank is different, but if you manage your live stock, feeding, etc. you probably don't need these things.


----------



## Charlie97L (Aug 14, 2007)

great thanks... i'll just keep it as is unless i have a problem down the road, then i'll re-assess.


----------



## Bert H (Mar 2, 2004)

If you angle your spray bar slightly upwards to cause a little rippling of the surface, you will diminish any film build up there.


----------



## gf225 (Mar 26, 2005)

Hi Charlie

This may interest you - 
http://www.practicalfishkeeping.co.uk/pfk/pages/blog.php?blogid=116


----------



## hoppycalif (Apr 7, 2005)

That is a good article George. I really like the video clip showing the microbubbles! Another way to use CO2 is to compromise between the 24/7 running of CO2 and running it only when the lights are on: try turning off the CO2 at night, but turning it back on about 4 hours before the lights come on. That will give plenty of time for the ppm of CO2 to stabilize before the lights come on, and still reduce CO2 usage by about half compared to the 24/7 scheme. It will still cause pH changes, so if that is a major concern, running 24/7 might be better.


----------



## houseofcards (Feb 16, 2005)

What is the known disadvantage of the pH change anyway? I've never noticed any problems with my fish or shrimp. Is there a disadvantage to the plants? Aren't most of us experiencing PH changes anyway when we do our 50% or so water changes?


----------



## hoppycalif (Apr 7, 2005)

houseofcards said:


> What is the known disadvantage of the pH change anyway? I've never noticed any problems with my fish or shrimp. Is there a disadvantage to the plants? Aren't most of us experiencing PH changes anyway when we do our 50% or so water changes?


I don't think there are any disadvantages, but if someone does believe there are, then shutting down the CO2 at night does cause a cyclic pH fluctuation.


----------



## gf225 (Mar 26, 2005)

houseofcards said:


> What is the known disadvantage of the pH change anyway? I've never noticed any problems with my fish or shrimp. Is there a disadvantage to the plants? Aren't most of us experiencing PH changes anyway when we do our 50% or so water changes?


It may be pure coincidence, but when I used a solenoid I had some crypts leaves melt regularly - about 3 or four leaves per day.

I switched to 24/7 CO2 - no melting.

Could be pH and/or CO2 fluctuations? Or something else.


----------



## houseofcards (Feb 16, 2005)

gf225 said:


> It may be pure coincidence, but when I used a solenoid I had some crypts leaves melt regularly - about 3 or four leaves per day.
> 
> I switched to 24/7 CO2 - no melting.
> 
> Could be pH and/or CO2 fluctuations? Or something else.


I'm certainly not going to say it's not from the ph change, but I've never noticed this with my crypts and I shut co2 off at night and do 50% water changes weekly with tap water that is 7.5 and tank water that is 6.5. George, just out of curiousity what is your tap and tank ph?


----------



## Charlie97L (Aug 14, 2007)

that's a great article...

i'm thinking of running mine 24/7...

so how much flow are we talking about here? most of the powerheads out right now are waaaay too powerful for something like this.


----------



## gf225 (Mar 26, 2005)

houseofcards said:


> I'm certainly not going to say it's not from the ph change, but I've never noticed this with my crypts and I shut co2 off at night and do 50% water changes weekly with tap water that is 7.5 and tank water that is 6.5. George, just out of curiousity what is your tap and tank ph?


Well, I haven't tested my water in over two years. I do use a CO2 dropper (4dKH ref.) though.

When I did test, tap pH was around 7.6, KH 7, GH 14.

With CO2, tank pH is around 6.6.

1/3 WC per week.

So very similar to your parameters...

I guess I have fussy crypts! C. wendtii were the main culprits.


----------



## longhornxtreme (Feb 20, 2007)

It was my understanding that fish are much more sensitive to a change in TDS which 'usually' accompanies a pH shift. When we get a pH shift due to change of CO2 concentration it is not altering the TDS which is why fish and inverts tolerate it much better. You've gotta remember that pH just means 'negative log of the concentration of hydronium ion' but there's ALOT of things that can cause that change in the pH. I felt that pH by itself is more of an indicator of a potential stressor to the fish. It just depends on WHAT made the pH shift. I.e. pH shift due to co2 intake and outtake is not harmful, but pH shift due to adding acid or base solids changes TDS along with pH. Where it's really the TDS change and not the pH change that harms the fish. 

Can someone correct me if I'm wrong?


----------

