is it possible to supersaturate with oxygen?

1. is it possible, with multiple pumps and a big protein skimmer, to supersaturate a 2,000gallon cold-water (54F) aquarium?

2. Can you measure 'supersaturation', that is, what will a DO meter read?

The system is a connected series of 10x200g fiberglass bins filled with chilled seawater to house local California invertebrates. A very large ETSS protein skimmer might be the culprit, but it is plumbed such that it dumps into one of the 200g bins which sits a few inches higher so passively poor into a second 200g bin before being pumped into the remaining bins. this seems like adequate 'degassing' but perhaps i should add bioballs?

The assumption i am making is that excess oxygen from the PS and pump agitation will 'float' to the surface, but I think that is incorrect. That is, supersaturated oxygen is not buoyant and requires flow and interaction with the surface to degass!

any comments will be really appreciated!

Regards

 

I kinda get the feeling you may have been intoxicated when you posted this, because your kinda raving and its a weird question.

cold water does hold more oxygen then warm water, but in order for it water to become supersaturated it would need to drop in temperature then saturate then warm. even then probably not for long.

you can aerate your water all you want it will never become supersaturated, because things don't want to be supersaturated, the solute will quickly precipitate or be freed(in this case).

I'm sure your DO meter will read what ever the amount in the water is.

Also its not like your PS pumps in pure oxygen it pumps in regular old air, akin to just having more surface area.

I'm really not sure why your worried about this, I'm not a chemist but nothing in your tank will ever die from being supersaturated with oxygen from your pumps.

 

LOL! I wasn't intoxicated but i had a lot going through mind and i wanted to ask a question with as few details as possible. thanks for taking time to sort out my ramble!

I have a colleague who has failed several times trying to culture adult tunicates in this system. Each time animals are collected in the field and placed in the system, within weeks they develop fatal air bubbles along the margin the colony and glass slide from which they are transferred too (from their native habitat of mussels or other encrusting material).

Supersaturated oxygen is a known killer of marine invertebrates, but the case that is being cited is from a coastal research center that brings sw from the ocean at depth rapidly, which causes the gas to expand. They found it necessary to degass the water by running it through trays of bio-balls.

I am actually more concerned with LOW DO, and need to survey the system with a DO meter in low flow sections, but want to make sure there is not some perfect storm with hardware that is actually saturating the water with oxygen.

1. Do micro-bubbles generated from pumps and protein-skimmers have the capability to transfer long distances? That is, if they are not settling out in the sump tank design, can they make it into the main system which could be a potential source of bubble.

Thanks!

 

When you say "super saturated," do you mean the chemistry term, or do you mean that it just has a lot of dissolved oxygen?

 

Micro-bubbles can but need high flow to do that. With the design you have described I think you should have little problem if at all.

 

well I guess going from high to low pressure will supersaturate, but seeing how they survive for a few weeks this isn't the problem.

I guess microbubbles could be a problem but they are visible to the naked eye.

I would be more concerned about water parameters, temperature and feeding. Especially the feeding, I think they are very selective about what they can eat.

btw you should probably have a refugium, and becareful the skimmer may be removing any plankton in their.

 

do you have any pictures of your system?

 

Just received this quote from a friend:

Seawater can be especially problematic for gas super saturation (dissolved N2 is worse than O2) and usually the problem is on the suction side of pumps or piping that has severe restrictions that cause high pressure differences. In larval fish culture, we always used degassing columns that were basically a 4" PVC pipe about 3' long, filled with chopped up pieces of 1" PVC inside. Water is introduced from the top and a screen holds everything in on the bottom. Worked great.


"When you say "super saturated," do you mean the chemistry term, or do you mean that it just has a lot of dissolved oxygen?"

Great question: The arguments is that atmospheric air is being forced into solution, so i guess that would result in a lot of dissolved oxygen, but is there another definition? At what concentration does DO become lethal 20 mg/L, 30?


"do you have any pictures of your system?"

Picasa Web Albums - Darren Atthebeach

Pretty standard stuff, nothing fancy. That Legacy Chiller -on piece of ****. It didn't last 2 months before the plate-style evaporator clogged and blew up. 8K down the drain. Now we have an Aqualogic titanium barrel design which works great. Tangster was super helpful back in the day!

Thanks for reading!

 

ok I have done a little bit of reading and I think your problem could be microbubbles. Have you tried installing baffles?
I don't really think supersaturation is your problem because people have kept tunicates in aquariums before, unless the low temperature makes a huge difference..
what do you feed them?

 

"Have you tried installing baffles"

Not sure if the Picasa link worked, but you will see in Pic 3, the drain from the skimmer flows into a 200 gallon tank, that is connected to a second tank via 2-2" pvc pipes that elbow down to the bottom so the intake is 25" under water! In addition, the 2 system pumps that direct the water around the room, have intakes as well 25" inches under water, so i am really scratching my head how these microbubbles can persist.

Do baffles slow microbubbles at the surface or in the water column?