theres nothing wrong with 7.2. the problem wityh those 7.0 buffers is that they wont work forever and you are usually adding alot of phosphorus to the tank. it winds up being bad for the plants and makes your pH more unstable b/c the pH will eventually rise again and you have to keep adding more. i wouldnt add any. I would also get your own test kit and not rely on the LFs to tell you how your water is. It helps to know the actual readings.
If you are really worried about the fish, and whatever it is is affecting all of them, maybe you should treat your whole tank with some sort of broad range antibiotic. Maybe set up that 55 and be ready to use it as a quaratine tank.
I am going to toss some weird stuff out to see if anything could be related:
Fungus -- I have noticed since day one in this tank that some spots on the driftwood had a white/opaque fuzz. On top of this, anytime something is sitting in the tank for a short period (say 8-12 hours) like a shrimp pellet, or a recently deceased cardinal tetra, it is covered in this same type fuzz or fungus. I have never seen this prior in any of my previous tanks. I have lost quite a few more angels tonight, but none had any markings on them. One that is listless tonight and I suspect will be dead in the morning apears to have some on the top fin (white growth). But none of the others do??
The gravel I am using was from the previous owner of the tank. He had one 14" pleco and 2 - 14"-15" oscars. This tank had dark green/black long hair algae on everything. I took all apart and cleaned with diluted chlorox. The grave was removed, cleaned with water and then left to set out in the sun for 3-4 weeks on a plastic tarp. It was then reused in this tank once rinsed off. ** Please note that the 2 oscars from previous owner were severely scared from hole in head disease I beleive. I assumed any parasitic item would have been destroyed.
Well that is all I can think of right now. It is amazing how something that brings such highs in setting up can sink you to such lows. I feel extremely guilty for this occuring to these fish.
I will be reading more tomorrow as well as installing a new Tetra UV1 unit in-line. Hopefully that will kill any non-hosted parasite or other free swimming nasties.
Did you cycle this tank before you added all of these fish? didn't know they were dying. it probably is a bacterial infection. Honestly, next time use new gravel. Especially since the previous inhabitants had so many problems.
I think maybe you put the tank in shock adding so many fish and they may have had something that is just spreading through them. It's always best to start slow and quarantine everything. I just set up my 120 in May. I ran it with the plants for about a month before I added any fish. I added slowly, using my 55 and 10 as quarantine (both of which were already established tanks). It's now August and I have my last batch of fish in Quarantine in the 55 and then I am done. It's taken some time, but i'd rather be safe than sorry.
Good luck with everything. These forums and doing alot of research helped me get this tank going. i had never tried a planted, high light, CO2 tank before. I didn't even know you had to test anything other than pH and had never heard of doing weekly water changes. So, hopefully you will find these resources just as useful.
