PH shock

[Spydermsd]

Hi all, I'm new here. I had a catastraphy in my 120 gallon community tank 3 1/2 weeks ago. I did my usual 25% water change and cleaned one of four filters I have on this tank. This perticular week I clean my Ehiam 2128. Stupidly, I was rush to clean because my wife wanted to use the sink. When I put the filter back together I put the baskets in reverse. This caused the nasties to go back into the tank. I did not realise this at the time. I noticed during the week that the water was getting yellowish/ brown and my fish stopped eating. I did a water test and the PH was at the lowest reading of 6.0 on the chart. I did a 30% water change and added Carbon. By the morning the PH was 6.6, normal reading were always 6.8 to 7.0. By the next morning the PH was back to 7.0 however my fish have yet to get their apitite back. They do eat but not nearing as much as before. My three Dwarf Guaramis have totally stopped eating and are beginning to shrink and their colors are fading. They also have labored breathing. The only fish with hardy apitites are my Bolivian Rams and Corys. They all will eat frozen Bloodworms but I don't want to feed them this everyday. I realise that time is needed to have them recover but it has been 2 1/2 weeks since the problem was fixed and I would think things would be progressing better. I'm looking for suggestions, especially for my Guaramis. Here is some tank info:
120 gallon tank filtered by Ehiam 2128, Magnum 350 Cannister with Bio wheels, Pengiun 330 & Penguin Mini.
Presently: PH 7.0, Ammonia 0, Nitrite 0, Nitrates 20 ppm
weekly water change of 25%, moderately planted, floutite gravel
Fish:
4 CLown Loaches
3 Bolivian Rams
3 Dwarf Guaramis
10 assorted Corys
3 Ottos
1 Chinese Algea Eater
7 Black Skirt Tetras
6 Head & Tail Tetras
6 Black Phantom Tetras
1 Male Crowntail Betta (in a 3 gallon tank intide the 120 gallon)
Tanks been running with fish for 8 months
Thank you for your time, sorry about the lenth of the post

 

[OrionGirl]

Since you are not seeing a spike in ammonia or nitrites, I'd suspect that something else caused the pH fluctuation. Have mulm or additional waste in the tank shouldn't impact the pH, I wouldn't think. What are your KH and GH readings?

I'm not sure if pH shock could result in such a long term reaction--normally, a sudden severe pH shock will kill the fish, while a gradual change won't have much impact. You may want to double check your water source, and verify that it is stable. Seasonal changes often cause fluctuations in water sources and conditions, and a change in the amount of chlorine used, etc could cause problems in the tank.

 

[Spydermsd]

Thank you for the reply, I don't think it is a water problem because all three of my tanks use the same water and this is the only one showing a problem like this. I noticed today, Saturday, that one of the Dwarf Guarami has a very long string if poo hanging and it is white. I don't know if it's constipation or an intestinal infection, I would guess the latter. I never treated for something like this and I don't know if I should treat the entire tank. Any suggestions would be appreciated.

 

[Sumpin'fishy]

I, too, have a hard time believing that your media trays being reversed-order had any affect on your pH. I could run mine for a week in reverse and have no affects other than dirtier-looking water. Remember than while particles are in the filter, they are STILL in the water system, and affect it as they would sitting on the bottom of the tank. The only difference is that your tank is better looking, more clear, and algae can't use the poop as a (direct) food source. The nitrates, phosphates, and other chemicals are still broken down into the system.

I believe that while you were rushed cleaning the filter, something was contaminated, and put back into the filter. This is just my best guess, considering the info given. OG's idea about fluctuating water supply is my second guess, and also probable. I'd do at least weekly tests on your tank to check it's chemistry for stability. Use every test you have, until you are sure it's not changing. KH is something that is very likely the culprit here! I hope it works out for you.

By the way, the fluctuating pH may have caused the fish to be stressed enough for some latent parasites (possibly intestinal) to gain a good foothold and start winning. Extra clean water (twice as many water changes, at least), and a quality medication (only when you are sure of your diagnosis) are the best things at this point. Don't forget to remove the carbon for the meds. And, it's best to separate any sick fish from the group in a quarantine tank, then treat with medicines.

 

[Spydermsd]

Thank you for the info. KH, although I've never tested it, I would doubt it being the problem. It is city water, but we have a new system in out city, a few years old and best in the state. LFS's rave about the water here. My water parameters have always been stable and are stable on my other two tanks. I am going to do 25% water changes every three days and see if that helps. I must agree that the PH shock must have weakened the Guaramis most and something has taken hold of them. Don't know how the treat exept water changes and prayer! I hate to treat 120 gallons and I've never had success with Q-tanks. I'll treat the tank before removing them.