[bharada]

I woke up this morning and was about to administer my daily dose of ferts to my 29g when I see an Amano shrimp halfway up the rim of the tank. I tap it back into the water and pour in my ferts. I was just browsing through some of the shrimp archives and remembered someone mentioning that shrimp typically try to jump when water conditions are bad...but I haven't had any problems with this tank. So I step back and take a look into the tank...to my horror I see pink and white bodies littering the micranthemoides Then I see my fish at the surface gasping for air.

I started an airstone while I got out the Python to do a water change, took a sample of water out for testing and tallied my losses. Of the 20 Amanos I added last Friday I lost 14. Also lost were my rubber-lipped pleco and 2 Flying Foxes (don't ask :x ). Suprisingly all three of my ottos made it.

When I tested the water I found that the pH had dropped to 6.5 from the 6.9 it had been holding at since Thursday. The KH is 10 so CO2 went from ~40ppm to over 90ppm! I checked the CO2 regulator and it was still feeding ~1bps. Now I have it turned back to .5bps but I still can't understand why the CO2 concentration shot up as it did. Before I installed the pressurized CO2 I was running 2 1gal juice bottles that were putting out ~1bps and the pH never got below 6.8.

I also tested for ammonia and nitrites and found 0 ammonia, but .25ppm of nitrites (which dropped to trace levels after the water change).

I've spent a lot of time looking at this tank over the weekend (I re-scaped it on Friday plus added the shrimp) and never noticed any stress in any of the inhabitants. So I'm baffled. pH is back up to 6.9 after the water change but you can bet I'll be monitoring it closely for the next couple of days.

If I can find any silver lining to this event, it's that at least some of the Amanos survived so I know I do have a few hardy shrimp in the mix.

Sorry for the novella, but I had to vent.

 

[Troy Hendrickson]

The increased nitrates indicate a disturbance in the biological filtration process, it might actually be a combination of adding 20 living organisms which increased the bio load and stirring up detritus and debris from the re-scaping.

I can't count the times unfortunately that I've turned nicely functioning tanks into complete disasters from the urge to re-scape things. Going in a ripping up plants and moving things around in a tank that has matured and balanced itself is a massive disruption really and it takes awhile for things to even out again. I have doubts as to the CO2 system being all that much of a factor really, tank CO2 is fairly constant, fermentation can be unstable somewhat with room tempertaure changes etc.

Of course this is just an opinion based on my experiences, and I live in Iowa which most likely changes everything :shock:

 

[MatPat]

Like Troy said, the nitrite increase was probably due to uprooting the plants and adding the Amanos.

I would guess that uprooting the plants has also caused the plants to decrease consumption of CO2 while they adjust to their new locations and re-root themselves.

I would keep an eye on the CO2 and make sure it doesn't drop too low once the plants begin to use it again. Low CO2 may be cause for some green water.

 

[bharada]

Thanks guys. I've been watching my pH and even when I cut the CO2 feed back to .5bps it was still falling. I cut it back even more to maybe 1 bubble every 3 seconds and the pH seems to have stabilized at ~6.8 (6.84 according to my Milwaukee pH meter).

One thing that I did notice last night was that my Magnum 350 (which I use as my CO2 reactor) was making a lot less cavitation noises, so maybe a lot of trapped CO2 in the 350 got dissolved and shot the concentration up?

 

[MatPat]

If I'm not mistaken, both Troy and I use a Magnum for a CO2 reactor. Maybe he can give us a bit of help too.

Did you by chance swap out the micron filter for a clean one after you re-scaped. I have noticed that when I put in a clean micron filter, my Magnum doesn't spit out as many CO2 bubbles. It would seem that the new filter does a better job at allowing the impeller to "chop" up the larger CO2 bubbles. Towards the end of the week I find that my Magnum gets a large amount of CO2 trapped inside, I assume due to a dirty micron filter. I swap the micron filter out and no more CO2 in the cannister.

 

[bharada]

Nope. I just have the media basket (filled with some lava rock) covered with a foam sleeve then a poly sleeve. Basically, the filter was set up for a fish-only tank and I never bothered changing the filter media when I converted to a planted tank.