Nothing survives....

[DonCollins]

Stability is essential in these closed systems. Correcting the PH swings, would be a step in the right direction, if not the solution. Good gas exchange and proper aeration are components of a healthy tank. I've never used lids, jumpers or not.

But isn't my QT just as unstable as my DT with the pH fluctuation? Is it more detrimental in a larger system? I thought aeration & gas exchange were done adequately via protein skimmer, 4 outflows from sump, & the 2 powerheads? I did switch to a covered tank right before the power outage (going on 2 years ago), but did not notice an immediate problem. Could this have been an insidious issue that worsened since then with the tank covers & now has reached the breaking point? Also, my 20 gal QT is also covered except for a small strip at the back, although it does have aeration stirring up the entire surface at the top. Is that where I'm lacking in gas exchange? My DT is very smooth on the water surface with very little disruption since I always had the powerheads pointing out not up. How would I know for sure that I have a dissolved oxygen issue? I'm gun-shy to place anything in it without knowing for sure what the issue is & that I've remedied it. Thanks so much for your expertise!

Don

 

[mr_X]

I'm not sure it works that way. I would think that covering the tank would show a PH change almost immediately- as soon as the oxygen was depleted.
Try taking the lid off and aiming a power head upwards. What can it hurt?
Yes, the skimmer does aerate the water, but is it enough?
I've always been told most of the gas exchange is done at the water surface, so I've never considered closing that hole. I also made sure that I could see a good amount of turbulence at the surface.
I don't think you answered my air stone question. Do you have an air stone in the tank? If so, I wonder if there's any truth to that "air bubbles in fish's gills" theory. Also, if you do, this would also be helping gas exchange- unless the nitrogen gas is being trapped at the surface and not leaving the system?.....I don't know.

 

[mr_X]

Then there's the room itself. You know you can change the PH of your tank by opening a nearby window? This is a new location, correct? Maybe that has something to do with it.

 

[somethingsfishy]

So your DT is in one room and your QT is in another? I originally thought equipment since the QT water came from the DT but maybe it's the room.

 

[GouldFever]

I truly believe you have an electrical current flowing through your DT. It can be subtle enough that you wouldn't feel it. I would turn everything off and introduce a fish (net at the ready) and observe from there. Makes no sense to me that your QT and DT have same water but one tank is toxic. It clearly isn't the water

 

[mr_X]

The shrimp and other inverts would be dead as well as the fish if it was electricity, wouldn't they?

 

[DonCollins]

I'm not sure it works that way. I would think that covering the tank would show a PH change almost immediately- as soon as the oxygen was depleted.
Try taking the lid off and aiming a power head upwards. What can it hurt?
Yes, the skimmer does aerate the water, but is it enough?
I've always been told most of the gas exchange is done at the water surface, so I've never considered closing that hole. I also made sure that I could see a good amount of turbulence at the surface.
I don't think you answered my air stone question. Do you have an air stone in the tank? If so, I wonder if there's any truth to that "air bubbles in fish's gills" theory. Also, if you do, this would also be helping gas exchange- unless the nitrogen gas is being trapped at the surface and not leaving the system?.....I don't know.

Last night, I removed both old power heads (one of which I think can be put back in the tank) and put one new 700gph power head in facing the surface (creating significant turbulence) and I removed the glass tops. I still have the old milk crate tops from a couple years ago which I think I will put back on once I try introducing fish again. The air stone was removed with the glass tops, but I had air in the tank from day one until last night. Some of the fish used to seem to like playing in the bubbles and I don't know that I saw a difference in life expectancy between the ones who swam through them frequently and the ones that avoided them. Honestly, though, thinking back past Sandy and the power outage, I really do think the start of our problems correlate with buying the glass tops. I will be heading back to the LFS again this evening to get a oxygen saturation test and I will report the findings!

Assuming this is the problem (and I do think it is at least the bulk of the problem) how long should I wait before trying to introduce a fish again?

Don

 

[DonCollins]

Then there's the room itself. You know you can change the PH of your tank by opening a nearby window? This is a new location, correct? Maybe that has something to do with it.

The location is the same since May 2009. The setup is new as of December 2012/January 2013 since we dismantled the old setup so we could bring the new stand in.

 

[DonCollins]

So your DT is in one room and your QT is in another? I originally thought equipment since the QT water came from the DT but maybe it's the room.

Yes, the DT is in the family room and the QT is in a spare bedroom. The QT actually gets more natural light, and the old old set up (before May 2009 when I moved to our current home) also got more light than the current DT.

I truly believe you have an electrical current flowing through your DT. It can be subtle enough that you wouldn't feel it. I would turn everything off and introduce a fish (net at the ready) and observe from there. Makes no sense to me that your QT and DT have same water but one tank is toxic. It clearly isn't the water

I intend on looking deeper into this in the near future. It is the next step after getting an oxygen saturation test!

Thanks Again Everyone!

Don

 

[DonCollins]

The shrimp and other inverts would be dead as well as the fish if it was electricity, wouldn't they?

The shrimp, crabs, and snails have all died as far as I can tell, but they did long outlive any fish that were introduced. The shrimp lasted at least 5 months and some snails longer than that.

 

[mr_X]

5 months getting zapped? Unlikely.

 

[mr_X]

You are using 700 gph power heads in a 125? You should have 1500 gph power heads.

 

[somethingsfishy]

So we're back to something leaching. Did you use any chemicals in the dt that may have bound to the rock? Any newly siliconed parts added? Copper?

 

[somethingsfishy]

Do you use any media bags in your QT?

 

[huma-huma]

its not copper, if it was, it would of def wiped out the inverts way faster than the fish.
id rule out the water itself, id say contaminated water isnt possible due to the inverts lasting months.
electricity id rule out as well, id like to believe that if the OP isnt feeling even a slight tingle from touching the water, then its not going to instantly kill fish.
are you running carbon filtration on the qt?
the 2 things id do, just to completely and totally rule them out for good, is 1) lab test the water.
and 2) do a side by side comparison, get 2 of the cheapest sw fish you can, get them home, bag float them in the qt tank, then simply fill a container with DT water, set it right next to the DT, then release one fish into each tank, the DT and the bucket of DT water. if they both die, idk im at a loss of thoughts, IF just the DT fish dies, then id say theres a contaminant in the water,
its worth mentioning that if you do this experiment, you may want to physically unplug EVERYTHING on the dt, this will ensure you are fully eliminating that aspect.

 

[DonCollins]

You are using 700 gph power heads in a 125? You should have 1500 gph power heads.

1500 gph each or total water flow? The gentleman who sold us our 55 gallon in 06 recommended a minimum of 12x the tank volume of circulation excluding the filter return (I had a canister with that tank) so I figured the 700gph and 900gph power heads I had in there were sufficient. If not, I can definitely add more!

So we're back to something leaching. Did you use any chemicals in the dt that may have bound to the rock? Any newly siliconed parts added? Copper?

No new silicone parts added. When I did the reset, the bulkheads were sealed with silicone, but that has been 13 months and no new silicone has been added since.

Do you use any media bags in your QT?

No media bags, but I do use carbon in the filter (a Marineland Penguin over the back.) Really, there is nothing in the sump for the DT that is not in use in the QT (skimmer, carbon, foam) except for the UV sterilizer.

Don

 

[DonCollins]

its not copper, if it was, it would of def wiped out the inverts way faster than the fish.
id rule out the water itself, id say contaminated water isnt possible due to the inverts lasting months.
electricity id rule out as well, id like to believe that if the OP isnt feeling even a slight tingle from touching the water, then its not going to instantly kill fish.
are you running carbon filtration on the qt?
the 2 things id do, just to completely and totally rule them out for good, is 1) lab test the water.
and 2) do a side by side comparison, get 2 of the cheapest sw fish you can, get them home, bag float them in the qt tank, then simply fill a container with DT water, set it right next to the DT, then release one fish into each tank, the DT and the bucket of DT water. if they both die, idk im at a loss of thoughts, IF just the DT fish dies, then id say theres a contaminant in the water,
its worth mentioning that if you do this experiment, you may want to physically unplug EVERYTHING on the dt, this will ensure you are fully eliminating that aspect.

The introduction bucket last night was at least 75% DT water at the end, and the fish were 100% fine in the bucket. That being said, this is an interesting test and one I think I will try. I took the top off and made sure the surface is turbulent for gas exchange, hopefully eliminating any oxygen saturation issues, and the QT could surely support two damsels if this test goes terribly wrong.

If this fails, the next step will be lab tests and as a last resort stray current tests!

Don

 

[huma-huma]

youll eliminate the stray current possibility by simply unpluggin everything on the DT when doing the experiemnt. 2 birds, 1 stone

 

[DonCollins]

youll eliminate the stray current possibility by simply unpluggin everything on the DT when doing the experiemnt. 2 birds, 1 stone

Ahh, that makes sense. Good call!

 

[DonCollins]

Ok, update for this evening.

I purchased a Mutimeter to test current and found that I was at 4.1 volts. I removed an old heater and put a new one in which dropped it to .7 volts. Before introducing fish, I also tested the newer of the two old power heads and found it was emitting over 4 volts of stray current which leads me to believe that this was part of the problem. I found the .7 volt to be coming from the two return pumps, both of which are just over 1 year old. No other items seem to be adding any voltage to the system.

Overnight and today, the top was off and one power head was aerating the surface. I also purchased another new power head and positioned it to aerate the surface as well. I drip acclimated 2 Yellowtail Blue Damsels, put one in a bucket of tank water and the other in the tank (in a large, 10" x 10" net with swimming room) and both seem to be doing well for the time being. I put him into the tank with everything unplugged and slowly plugged items back in to see if any of them had an effect on the fish and none appeared to.

So, as of now, both have been in the DT for about 1 hour and are acting essentially normal for fish that just went through a transfer. I plan on leaving them in the large net overnight just in case there are issues, but, fingers crossed, I will be able to let them swim free come morning.

One more question I do have is about two inverts currently in our QT. Thinking I had our problem solved yesterday, I purchased a sand sifting star and a cleaner shrimp (and a sand sifting goby) that I figured would be fine in the DT....since there were issues with the introduction last night, they were acclimated to the QT instead. How long are they safe to keep in an essentially bare QT before we -have- to either reintroduce them to the DT or take them back to the LFS?

Thanks to everyone who helped me out. The two items that I think contributed to our major problems I would not likely have discovered on my own. With your help, a discouraged marine aquarist is going to continue with the hobby instead of throwing in the towel!

Thanks Again!

Don

PS-the Poly-Filter discussed yesterday is turning a light brown indicating nothing more than organic waste. I take that as a good sign!