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Lets play detective

Garuf

Member
Joined
30 Oct 2007
Messages
5,644
Location
Copenhagen
I present to you a mystery who done it.

My green rasbora's have been in quarantine and fattening up nicely since just before Christmas and I want to shut that tank down, so I did the same as I do when I add shrimps to the tanks.

I did a 50% water change before co2 comes on in the morning to reset any build ups, add ferts and 2ml of glut and then did another 50% water change at co2 off to take of as much co2 as possible, add ferts (2ml tropica green) and 2ml of glut.

I then catch the shrimps/fish I want to transfer and drip acclimate them, 2l of current tank water to 8l of new tank water over around 2 hours, I leave them for an hour and then net in the fish/shrimp and top up with the mixed water. I watched for around half an hour and they settled fine, no red gills, coloured up well, started to test the tank.

The tank when I first added shrimps at around 3 weeks old I suspected was still going through an ammonia spike that I didn't pick up on the test strips, so when I first added shrimp as they were all at the surface every morning, I'd do a 50% water change after about a week of finding them like this every morning things settled and they'd be doing their normal shrimp thing every morning, Hurray.

So today I get up, do my thing, peer at the tank and find ALL the still living shrimp at the surface, half a dozen dead shrimps stuck to the filter guard and ALL the fish going in circles gasping at the surface and a couple of crispy jumpers. 50% panic water change. Everything back to normal, you'd think nothing happened.
First thing after the water change, is check the co2 timer, wouldn't be the first time I've knocked it or one has failed on, Drop checker is lime/yellow, everything a-okay on the timer. Add a second drop checker and make sure it's definitely not co2, still blue after 2 hours, original drop checker still yellow.
Grab the test strips for a quick and dirty, nitrite, nitrate, ammonia, ph, nothing unusual, all undetectable on the kit. Ph 6.5.

So what have I done in the tank that might cause a spike in something, well, nothing that I can think of. I did a BIG trim last Sunday and of course, the big water changes to reset the tank. The shrimp were happy prior to today which is why I was confident to add the fish.
Other notables - the tank is a mix of aquasoil Amazonnia and Tropica.
Tank has some start up algae, namely a reallll mean case of staghorn.
Co2 is via a jbl inline and it's kinda "squirty", not really a proper mist.
Filter is an experience 150. Was seeded with a mix of mature filtermedia and a good squeeze of mulm.
I dose 2ml every day of tropica green and water change every 4th day.

What are the obvious things I'm missing?
It's gotta be co2, right, but how? It should have been reset by the water change.

And what to do now to fix this mess?
 

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What about oxygen in the water? Do you have enough surface movement, or any surface scum preventing gas exchange? Since the livestock has issues mostly in the morning that would be my primary suspect. I'd increase surface movement, especially at night, and if you dont have one yet and you have scum on the surface, install a skimmer.
Option 2: Did you remove a lot of plant mass? That could have reduced CO2 uptake/O2 release.

Or perhaps its something else entirely, in which case I hope someone else can point that out... good luck either way!
 
Surface agitation is so so, not insane but a nice spin, I have no film so I hadn't really worried to raise the lily.
O2 I worked on the "everything's pearling" notion but you're right o2 would be my first point.
Mass taken out would be 2/3rds of the stem plant mass roughly. A really big trim.
 
Hi all,
It's gotta be co2,
What about oxygen in the water?
It is a bit of both, how the livestock respond depends on the <"(Bohr) Root effect">, and Shrimps have haemocyanin as the oxygen/CO2 carrier in their blood, which is less efficient (and they have a less efficient circulatory system) than vertebrate haemoglobin.

cheers Darrel
 
Surface agitation is so so, not insane but a nice spin, I have no film so I hadn't really worried to raise the lily.
O2 I worked on the "everything's pearling" notion but you're right o2 would be my first point.
Mass taken out would be 2/3rds of the stem plant mass roughly. A really big trim.
yeah this is one of the reasons why I dont go for max CO2 anymore, a big trim of plants or some scum can already cause issues with low oxygen/high co2. I trim plants in batches too instead of all in one big trim, to reduce the impact. And I have a skimmer on in the morning to create some extra surface movement. Perhaps I'm too careful, but I once accidentally gassed my tank and had all the fish gasping and near death, luckily I was in time to prevent deaths somehow, but ever since I use the 20mg/l CO2 test liquid. That way I know if that goes past limegreen I still have some leeway, and tbh I've not noticed my plants reacting poorly to that. I dont have very demanding plants though.
 
This kinda puts me off from ever having Co2. There seems to be quite a fine line between having the right amount, and things going wrong.
It kind of depends... lots of people aim for that 'perfect' 30 mg/l, but you can aim for a lot less too, as long as its stable and your plant choices/fert regime match it. I aim for 20-25mg/l so I dont risk accidentally gassing livestock as easily, and they seem a lot more active then.
 
Kh is around 23 last time I checked. It usually gets harder in the summer and is more like 28dH then.
 
Garuf stated......The drop checker is lime/yellow.

Definitely pointing to excessive Co2 dosing....Over 40ppm.
Aim for a Green colour in the drop checker if you have livestock.....have some surface agitation at night!
Removing a large plant mass would see the accumulation of unused Co2.
If you are aiming for a 1 point drop from saying pH 7.5 to 6.5......you could be continuously in the overdosing range if your not gassing off Co2 with surface agitation.
 
This is true, but I did a 50% water change and hadn't injected any more co2 - I went straight into lights off. In my mind I'd reset the clock so to speak by doing the water change before adding fish?
 
I'm not much of a mathematician if your removing 50% of water twice and you intialy have 190ppm Co2 based on the chart below the remaining water would still be in the toxic range for critters even after doing two water changes!
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hoggie
 
Hi @Garuf
I had left co2 running on all night by accident, upon transferring fish, my ottos looked like the were going to die (I could hold them in my hand and they would not go anywhere, my green rasboras were not good and I really panicked). I noticed the drop checker was yellow! checked co2 and it was on when it should have been off. So I turned off co2, did a 70% water change and added an pump and airstone. All fish survived and were looking good over a 1.5hr period.

I keep my co2 and air pump on manual timers which has helped. Airstone comes on 4hrs after co2 / 2hrs after lights are off.

Check your dKH again....your dKH is really high and makes me think it is definitely excessive co2. What plants do you have, maybe you could remove the co2 for a bit to see if things settle down.

Hope that helps
 
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WELL.
I thunked I'd got to the bottom of it when the timer appeared to be still on 2 hours after it shouldn't be. Another big 50% water change, check the drop checker, yellow, fish gasping again. Check the bubble counter, co2 going like mad. Checked the regulator, empty. My speculation is that the pressure spiked and was getting past the solenoid. It is only speculation however.
I use a 10kg tank so didn't expect to have an empty tank until June so much head scratching and checking for leaks, new tubing fitting off we go...
New tank fitted. New timer fitted. Everything checked. Bubble count sensible, drop checker green. We see what things look like in the morning.
 
Gaspers. Again.
No co2 was injected during the afternoon/evening yesterday and the drop checker was very dark green at lights off. At lights on it was still very dark green almost blue.
Only thing I can think is a dirty filter and a trip to get a test kit rather than strips to see if there's something more going on I'm missing.
 
I'm convinced co2 is the red herring here - something else has to be at play for no injection to still be resulting in gasping. High organics could use up the o2, plants respiring... Something is off somewhere.
 
Id suggest looking back at lack of oxygen rather than too much co2. Can you run an airstone overnight. I've had an oxygen crash overnight before when first starting out. Plants maybe the only thing keeping the level up during day and when they switch to using oxygen at night might just be on the limit to cause issues. I'd give the filter a clean as well to make sure its not clogged up. I find after first setup there are lots of particles and it blocks up quicker then normal running?

I might be well off the mark but that's where I would start if it was my tank
 
Sounds like a CO2 issue to me...
second drop checker and make sure it's definitely not co2, still blue after 2 hours, original drop checker still yellow
Drop checkers are relatively quick to respond to CO2 increases but slow in comparison to respond to CO2 decreases.
I did a BIG trim last Sunday
Could be, less plant biomass - less CO2 demand - higher CO2 conc in water column.
Co2 is via a jbl inline and it's kinda "squirty", not really a proper mist.
Inconsistent CO2 application?
Is the inline plumbed in before or after the canister filter?
If before, CO2 could have become trapped in the filter and released all at once; CO2 dump.
 
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