Circulation & Current In A Co2 Planted Tank

[sophos9]

Hi,

I'm only using the filter output which does not move the plants at the back or circulate the surface at all, this seems to allow algae to build up (may be totally wrong, this is just an observation). I've also got another thing, any new fish when introduced to the tank immediatly hit the surface gasping which points towards O2 problem (all other fish do not do this, maybe they have become acustomed to low o2?)

I've just changed the CO2 diffuser and have it poitioned below a 300pa Eheim Pump (positioned on the left side of the tank) which blows the diffused bubbles across the tank, the spraybar is poistioned on the same side, in the same direction. This is pushing the plants around (not stupidly) and agitating the surface slightly. I've also rigged up an airpump to the old diffuser and am diffusing O2 below the spray bar

Well the question...

In a CO2 planted tank, why does it seem that there is an O2 problem when the saturation of O2 should be greater than what any airstone should be able to produce

How will having a current which sways the plants around affect pearling?

How does circulation affect algae growth?

All this is doing me nut in now

 

[nry]

Wierd, I just read something about circulation via Tom Barr's website, a very worthwhile site to peruse and a very logical discussion on the subject:

There is a balance where circulation is enough to move CO2 across the plant but not enough to drive off most of the CO2 at the water surface. Plants which are subject to this 'best' circulation will have less algae because they are growing better due to more CO2 being available. If water circulation is low then the plant will not get as much CO2 hence will not grow as well hence will attract algae.

Too much current will therefore drive off CO2 and have the relevant affect on pearling because plants will not be getting enough CO2 due to it being dissipated by the circulation.

The fish gasping could be related to a rapid pH change, I have seen this when I had a major crash ages ago (due to CO2 and other things), my cory all started darting to the surface every few minutes as opposed to their usual every few hours. When you add new fish do you gradually add tank water to their bag as well as acclimatising the temperature? If you don't do this then the pH change when they go into the tank can (I am told!) cause a quick build up of mucous around the gills which reduces their ability to absorb oxygen hence the gasping.

 

[sophos9]

nry, excellent - thanks for sharing that!

Introducing fish is about an 30mins - 1hr affair dependant on the PH levels of where I bought the fish

I believe my CO2 will be pretty efficient (have already seen excellent signs) I also think I may have nailed the source of the problems experiences, just need to find out the effects of dosing too much CO2 then I will share

 

[idlefingers]

This is more questions than knowledge so correct me if I'm wrong, but if your plants are growing very fast, they'll be photosynthesizing loads to fuel that growth, the result of which would be more o2? And I think I read somewhere that pearling is a result of an abundance of o2 in the water to the extent that more o2 released from photosynthesis builds into small bubbles on the leaves.

If this is the case, perhaps there's something in your tapwater which the fish don't like rather than an o2 deficiency? Or perhaps it's ph, like nry said. I'm just clutching at straws.

 

[sophos9]

Hi idlefingers...

You are right about the levels of dissolved oxygen being higher although I have read (think it was on Tom Barr's website) that pearling and levels of o2 are not overly related, will look up the reference

I think I may have found root cause however I'm waiting on information about the effect of too much CO2 on algae...