Considering complete teardown / rebuild

[Felix T Cat]

About 3 weeks ago I lost both of my powder blue Gouramis to something. I was treating the tank and yet they still passed on. Since then I have done a number of large (50%) water changes and replaced the carbon in the filter but I am slowly losing fish (one pepper cory, one platty...). I thought that maybe I was getting a second cycle but so far Am=0, Ites=0, Ates=20.

I did notice last week while doing the water change that the sand (pool filter sand) had a grey coloration under the top layer ?. Any ideas ?.

I am considering moving everyone to quaranitine tanks this weekend and tearing the tank completely down. Dumping the sand ( or at least rinsing it well). and cleaning off the fake plants / rocks in the tank.

As a side note I have also noticed the water gets cloudy everytime I feed the tank (using the same food I always did, so this is a new issue).

Thoughts please ?

 

[coach_z]

You might want to quarantine but i have a few questions

Do you regularly stir your sand to eliminate/prevent any gas pockets from forming?
What did you do 4 weeks ago before you lost your gouramis?
What is your maintenance routine?
What were you treating your tank for?

 

[Felix T Cat]

I have only been cleaning the upper layer of sand when I do my water changes, vac off the debris on the top but not stiring up the sand.
No changes 4 weeks ago that I can remember (and I have been trying to figure out if something dramatic changed) but both of my powder blues developed open sores. I thought they were attacking each other but watching them, never saw it happen. I was treating with Mela and Pima fix.
Maint - Weekly 50% water changes, water from well with water softner. Used Prime early on but haven't used it in months.
Treating for fungal / bacterial infections based on the sores on the G's.