Some new fish...

[Recty]

It probably makes a big difference in the tank setup. I have my tank totally covered and most of my sump as well. Most of my oxygen exchange is my skimmer.

Do you cover your tank? Do you cover your sump?

I think I'm going to put a large airstone in the sump if I cant run the skimmer, but I've got a question email sent in to Seachem right now to see if it's OK to run the skimmer really low so it isnt collecting, just helping inject O2.

 

[Recty]

Well, everyone is doing good. The guys in the QT are spotless and eating like pigs, very healthy to my eyes.

The main tank is just starting to look like I still have ich. The achilles is totally clean...

The dussu is totally clean... in fact he has never shown a single spot of ich.

The emperor, though, looks like he is getting it now that I'm raising the salinity. But hey, that's why I'm treating the tank with copper soon

 

[Zoom]

Yes it is little ich on the Emperor.
Very nice fish you got there.
No cover for the tank or sump just a crate to keep the fish in the tank.

 

[Recty]

<a href=showthread.php?s=&postid=15049271#post15049271 target=_blank>Originally posted</a> by Zoom
Yes it is little ich on the Emperor.
Very nice fish you got there.
No cover for the tank or sump just a crate to keep the fish in the tank.

Well thanks, I like them too

You probably have an easier time with oxygen exchange because your tank and sump arent covered... mine are pretty tightly covered because I have to keep humidity down. The only way I get good, new fresh air into the tank is through the protein skimmer. But I can put a big airstone into the sump while I'm treating with cupramine, so that will be easy.

 

[barbianj]

Nice pecs on the Majestic.

I thought that most of the oxygen transfer occurred at the waters surface, and the best way to improve saturation was to agitate the surface.

 

[Recty]

<a href=showthread.php?s=&postid=15051655#post15051655 target=_blank>Originally posted</a> by barbianj
Nice pecs on the Majestic.

I thought that most of the oxygen transfer occurred at the waters surface, and the best way to improve saturation was to agitate the surface.

I'm sure there is some O2 exchange going on at the water's surface, however, my tank and sump are pretty tightly covered, so the amount of fresh air entering up there is going to be pretty negligible. If I didnt have a covered tank, that would probably work just fine for me though.

As it stands, I have lots of turbulence at the top of the water, so that might help a little bit.

I might even just remove one of my glass tops for the cupramine treatment.

 

[DamnPepShrimp]

Does your tank stink at all? I've heard its very bad to have a tank covered, there won't be any gas exchange. You are getting air into the system through the skimmer but air is getting trapped under your lids. Most of your air exchange will come from the surface of the display tank. I need to keep humidity down in my tanks as well, but covering the lids isn't a great idea. I have my 210g covered right now due to the eel. My basement (where both tanks are) is getting really hot and humid now. Having a window open with a fan going has worked wonders. You might want to look into something like that so you can have your tanks open and proper gas exchange. I've been doing a lot of research on this topic lately due to humidity and heat problems, might have to get rid of my tanks if I don't solve it completely and soon.

 

[Recty]

Hmmmm, no stinking at all, no. My house and tank dont smell much like the ocean like I was expecting it would when I added almost 250 gallons of water to a relatively enclosed area.

I think most hobbyists have their tanks covered, at least every tank I've ever seen here in Alaska has been covered. I really only hear about open topped tanks while reading on Reef Central, but most of us here arent the average hobbyist and do things "to the extreme" in a lot of cases.

Really, if putting lids on trashed a tank, I dont think manufacturers would get away with building the tank lids

It isnt as if it's an air tight seal by any means, it's just glass sitting on plastic, but it's pretty tight I guess.

I leave my glass deck door open most of the summer and just leave the screen door closed to keep the killer misquitoes out, I have decent air flow through the house. No humidity problems here, but in the winter when I close the doors I have to run a dehumidifier almost nonstop. It is a nice trade off though as it puts out heat while it does it's thing, so I dont have to run quite as much heat in the winter as I would if I had the dehumidifier off.

Anyway, I dont think I'm harming my tanks at all. I inject ozone through the skimmer as well which breaks down into nice clean O2 almost immediately. I run an ORP controller which in a roundabout way measures the oxygenation of the water, my levels are always very high, 370-400 which is near the top of what is safely recommended. Some sources even consider anything over 350 as too much oxidation potential. This is with the tank covered completely and just a skimmer running. That skimmer injects a LOT of air, I'm sure it helps work out CO2 and put in O2.

Long story short, I'm not worried about it. The tops keep my humidity down and my fish in. I have had LOTS of fish in there in the past, if I was dealing with a high CO2 and low O2 concentration it would have been a big problem with the large stocking list I had.

 

[anbosu]

Air transfer happens any time air and water make contact. It can be at the water's surface or below if the air is forced underwater (like in a skimmer). The amount of surface area touching the air is key, and in this sense it is possible that a skimmer is actually a superior air transfer device than just having an open top, because more surface area of the water (due to all the tiny bubbles) is exposed to air. A covered tank with proper equipment and water turnover shouldn't lack for oxygen.

 

[DamnPepShrimp]

I haven't had any problems with my 210g stinking at all, and it has a tightly covered top and the stand is fully enclosed (but the sump is open). I lose a 1/4 of what my reef does in evap, even with double the amount of water, just from having lids. I am thinking about putting lids on my reef now to help with the humidity and heat issues. Everyone is telling me no, I need proper gas exchange and I have personally heard from friends that had lids and their tanks stunk, they took the lids off and smell was gone 2 days later. Lids are mostly used for freshwater tanks btw, thats why they are in business. All the top manufacturers for tanks (AGE, glass cages, ten-cor, miracles in glass etc) all don't made lids for their tanks, so there is a reason for it. But whatever works for you, every tank is different, I'm sure most people don't inject ozone as well. I am torn on what to do. The open window with the fan is working good, but can't do that forever.

 

[anbosu]

A lot of the really big reef setups have fans built into their canopy that take the air directly outside. That is probably the ideal solution to the problem, but obviously not practical for everyone.

 

[barbianj]

I'm not familiar with skimmers adding oxygen to the water, but I had understood that bubbles add very little or no oxygen to the water column, and it was only when they break the surface does the exchange take place. I also thought that the amount of dissolved oxygen in the water is a small fraction of what is in the air, so you don't need huge amounts of fresh air circulating to supply what is needed for your fish.

DamnPep, I had about 1,000 gallons of water in my basement when I bred the piranhas. I had to keep lids on all of the tanks, or the humidity would have ruined my basement in a hurry. I kept the windows closed and ran a dehumidifier, which I had to do anyway, with no problems at all.

 

[DamnPepShrimp]

That is what I thought and understood as well, gas exchange only taking place at the surface. I think freshwater is different with evap and the way things work with saltwater, but I forget exactly what or why. Regardless 1000g of any water at 78* is going to cause problems. I run a dehumidifier a well, pullingout about 2g day. I still need to open my window and run a fan tho. When I move, I will put the tank near a window and have ducting run from the tank to the window with a fan blowing the humid air out.

 

[anbosu]

Gas exchange can happen anywhere water and air touch, unless it is under extreme pressure or something (like the bottom of the Mariana Trench).

 

[Recty]

<a href=showthread.php?s=&postid=15052969#post15052969 target=_blank>Originally posted</a> by barbianj
I'm not familiar with skimmers adding oxygen to the water, but I had understood that bubbles add very little or no oxygen to the water column, and it was only when they break the surface does the exchange take place. I also thought that the amount of dissolved oxygen in the water is a small fraction of what is in the air, so you don't need huge amounts of fresh air circulating to supply what is needed for your fish.

Yes, the dissolved oxygen in the water is a small amount of what is in the air, that's why fish can be shipped in a bag that has a lot of air in it for 24 hours and not die of lack of oxygen.

As far as it happening only at the surface, I dont believe that. This is a direct quote from Bob Fenner when asked about what benefits a skimmer brings to a tank...

Elevated dissolved oxygen, lessened carbon dioxide, raised redox... removal of phobic organics

Also when asked this...

"I've heard that if the O2 saturation of the water is low, use of a skimmer could assist in "blowing off" CO2 so that more O2 could be absorbed"

Bob replied with "Yes."

Always helpful and wordy, is Bob.

Anyway, I'm not saying protein skimmers are going to directly inject oxygen into your water, as the "stuff" your protein skimmer is blowing in isnt pure O2, but it is going to help with gas exchange. I can easily test that with my ORP monitor and have in the past. I didnt run my skimmer for a week while treating with prazi and my ORP levels went from 375+ to down around 200 rather quickly. Now, if I had pulled the tops off the tank, I bet it wouldnt have dropped so low and so fast, but with a good skimmer running I dont see the need to leave the top of the tank open for gas exchange.

 

[Zoom]

A cover over the tank is the way to reduce humidity in the home in the winter time .
A dehumidifier in the winter without i lid on the tank is a no no it will accelerate your water addition like 100%.
I never had any problems with a lids on the tanks if was skimmed with a good size skimmer, O2 was always good.
On a reef tank a lid will cut your light intensity by 20%.

 

[barbianj]

I'm not claiming to be an expert, or even be completely sure of what I'm talking about, for that matter, I'm just trying to learn here. There is something that I don't understand. Don't skimmers work because of the surface tension of the bubbles that allows them to collect stuff? I had been told that because of that same surface tension, that very little to no gas exchange occurred until the bubble broke the surface at some point. That is not to say that skimmers don't add O2 to the water, rather that it happens when the bubbles burst at the surface, creating agitation.

How did this thread go in this direction? Sorry, I'll have to go back a re-read.

 

[DamnPepShrimp]

I am thinking with Jerry. Skimmers can definitely add O2 to the tank, no question there. But gas EXCHANGE is when gas is added and taken away. With lids on your tank, you are trapping gas that needs to be dissipated. That is the problem that I have been told with lids and reason for having an open top. You may be adding enough gas to your tank but not relieving enough. Haha, this sounds too funny.

 

[Recty]

Might I suggest some 210 gallon sized bean-o then? I hear that helps relieve gas.

My little excerpt from wetwebmedia covers almost exactly those last two questions. Yes, a skimmer will help to blow off CO2 and yes, it will help to add O2. To me, that is gas exchange.

I dont doubt at all that a small amount of gas gets trapped between the top of the water and the bottom of the glass lids. However, that amount is so small in comparison that I wouldnt worry about it. Plus, I open one of the glass lids daily at least twice to feed, normally 3 times, and end up leaving it open for 5-10 minutes, so any small amounts of CO2 that build up have a chance to dissipate.

I'm not concerned about it either way. If I didnt have my ORP monitor I might be a little more concerned, but basically my tank runs at almost the max oxidation levels with the way I am set up, so that makes me happy.

Even without injecting O3, when I first just hooker up the ORP monitor and let it settle into a reading, I was slightly above 300. The O3 just helped drive it on up to even higher.

I dont claim to be an expert either, btw, so dont take anything of what I say for absolute fact I'm just going off experience and some reading on WWM.

 

[anbosu]

<a href=showthread.php?s=&postid=15057520#post15057520 target=_blank>Originally posted</a> by DamnPepShrimp
I am thinking with Jerry. Skimmers can definitely add O2 to the tank, no question there. But gas EXCHANGE is when gas is added and taken away. With lids on your tank, you are trapping gas that needs to be dissipated. That is the problem that I have been told with lids and reason for having an open top. You may be adding enough gas to your tank but not relieving enough. Haha, this sounds too funny.

At one atmosphere (the pressure on the earth's surface) water can absorb a certain maximum amount of oxygen, carbon dioxide, etc. Unless your glass tops are capable of creating a vacuum and sealing the contents of your tank at high pressure, it is physically impossible to have more than that maxiumum percentage of gas in the water. At differing amounts of pressure water can absorb more or less gas, but our tanks are generally not going to be large enough to really have this be an issue. Gas exchange is exactly what you are thinking, and if a skimmer is adding oxygen to the water, then it is clearly exchanging that oxygen for something else. It is probably going to be carbon dioxide -- it could be nitrogen or some other gaseous element in water, but an exchange is what is occurring. The only way it wouldn't be an exchange is if your tank had very low saturation levels before you started running your skimmer.