My 1st emergency

[Caltus]

Well its been a few months now that i have had my 29 gal, planted tank up and running. For the 1st month or so i had only plants. A few weeks ago i added some common plecos to take care of the growing algae problems. Yes i know they get big and i didnt plan on leaving them in there for hte durration. But that problem was solved for me when i cam home about a week ago and i had 1 dead pleco, and thismorning i woke up and saw the other one dead. Neither were flaoting though just sitting motionless at the bottom of the tank.

i am running 65 watts in a heavily planted tank with DIY co2,

I ran some tests today and while my PH is normally around 7.0 it is some where btwn 5.0 and 6.0, after the 1st fish died i did a 30-40% water change. i dose with the flurish products twice a week

my PH was about 5.5
GH = 5
KH = 3
NH3 + NH4 = 0
NO2 = < 0.3

the heaters been kicking on now that the temp is dropping and the temp is around 76 or 77 degrees

Thank you

Chuck

*update*

I set the fish that died this morning on a piece of drift wood cause it looked like he was still breathing. There is sitll al little life left, when i pick him up he tries to swim a little but doesnt have much luck. is this just reflexes or is there something i can do to help him

 

[happychem]

Stop using CO2 for now and do a 10% water change one in the morning, one at night.There is a chance that the pleco recovers and right now I'm thinking that your pH is the problem. For the next few days repeat this until your pH reaches about 7. It really shouldn't take very long.

I doubt either your pH or your KH reading, if they're correct, then you've got about 285ppm CO2 in your tank, which I do not believe possible to achieve with a diy system.

Once your pH is back up to 7 you can start considering CO2 again, but I think that you need to get a better handle on KH. If your KH was 3, you shouldn't have had a crash so quickly, not would your KH remain at 3 after the crash.

 

[Milky]

Plecos are known to sit at the bottom and remain motionless for extended periods of time... Are you 100% sure that the first pleco was dead ? From the sounds of it the second one is still alive and I would keep him in the tank. Usually when a fish is dead he will float to the top but ive never seen a pleco die so im not sure if they just sink of float... Im assuming they are young and relativly small plecos.. Your heater sounds like its ok... I think
its either the flourish product your using thats making them sick, A normal tank dosent require any type of med after its cycled only some stress coat when you do water changes and even that isnt a must. What is the flourish product suppose to do? As far as DIY CO2 you probably dont need to be using it and its probably effecting the oxygen level in the tank.. I dont really know what the benefits of CO2 is in the tank is ive never used and havent had any problems with dying plecos. Ive read some articles about people using it though from what ive gatherd it does more damage than good... I use surface agitation from my output nozzle to put oxygen in the tank dont know how adding CO2 will help. Hope you get the right info on how to save that pleco good luck .. :rant: :idea2:

 

[happychem]

CO2 does not affect O2 concentrations in any negative way. On the contrary, in a high light tank, the presence of CO2 along with proper nutrient dosing will supersaturate O2.

CO2 and O2 concentrations are on completely different scales, the partial pressure of O2 in a tank equilibrated with the atmosphere (i.e. by aerator or surface agitation) will be about 0.2 atmospheres. CO2 is orders of magnitude lower, even in a supplemented tank you will only increase CO2 by about an order of magnitude. In any case, you're still talking parts per million as opposed to percent (or parts per hundred).

To say that increasing CO2 decreases the relative concentration of O2 is technically true, since volume hasn't changed (or has it?), but it's like saying that you've lightened the weights you're lifting at the gym by dusting them, they are, but not to any appreciable scale.

The inherent danger of injecting CO2 is that if your water is not properly buffered, you can get a pH crash. I doubt the KH measurement presented and I believe that were a bag of crushed coral or laterite added to the filter, after the initial problem has been resolved, then CO2 could safely be added.