Aerating "fresh" Saltwater

[AK77]

Today I filled up 2 empty salt buckets with a fresh batch of RO water and added the salt as normal. I turned the pumps on and threw in an airline into each. I came back periodically to check the SG value and add more salt where required. On the 2nd trip back, to the shed/utility room, I heard this loud humming. I removed the lid and looked inside and couldn't see a thing but cloudy water. I turned the pump off to see what was going on and noted that one of the airstone had been sucked into the pump inlet. The result was millions of microbubbles circulating through the entire bucket.

I would have thought this to be a really good way to ensure your RO water is well oxygenated and PH stabilized before adding it to your tank. The only downside is that it does make the pumps a bit louder than normal.

Any thoughts on this??

 

[sophos9]

I guess any movement over a period of time should sufficiently add oxygen to water, personally I use a 600lph pump in a 25ltr container - dont know if there is enough oxygen as I have not measured it, I'm sure there is though - fishies are not complaining.

I was of the understanding that the bigger the bubble the better, the reason why is because as the bubbles burst on the surface, oxygen is then taken up. More diffused bubbles may create less surface disturbance. I used to do what you are suggesting when dissolving pressurised CO2 into the tank, this worked great although was completely different to what you are trying to do by oxygenating

 

[Mr Flagfin]

always been lead to believe that surface movement is more important than bubbles ???
or have i misunderstood the statement ?

 

[AK77]

Hmm, I'm unsure of this myself.

I was under the impression that since we don't want a mass of bubbles in our tanks, we utilize surface agitation to encourage oxygen exchange in the aquarium. However, wouldn't the fact that the amount of micro bubbles that were in the water bucket, lead to faster/more thorough oxygen absorbtion due to the increased surface area of air and water molecules in contact with one another? I couldn't see the tip of my finger at 2" deep into the bucket.

Where's Ski or Lynden when you need them??

 

[xxBarneyxx]

If it was pure oxygen you where bubbling in that yeah it would probably work very well (in the same why that you disolve CO2 in for planted tanks). I think the average oxygen content of air is about 20% so it might work (not sure how well oxygen disolves in water compares to CO2). It probably wouldnt do a great deal more then having really good surface movment though (depending on how deep the container is and how much surface area there is) and it will wear the powerhead out faster as most powerheads/submersed pumps are desgined to be used under water and the water acts as a lubricant for the moving parts.

The other thing to remeber is that there is only so much oxygen water can absorb. O2 saturation in saltwater (1.026) at 25° is about 6.5ppm so it probably doesnt take a great deal to get that much O2 into the water. Also I think the reason for airation is as much to drive the CO2 out as it is to get the O2 in and this wouldnt be done with just lots of microbubbles (the surface movemt would increase the amount of CO2 being driven out of the water.

Thats a little disjointed but hope it makes sense.