sick angels - tank harmony out of equilibrium

Question
QUESTION: Hi Lynda,
i'm at frantic point, i'm hoping you can help me! i've tried a few things so this might be a bit long as i want to give you background.

in summary, my angel fish have open wound holes in their scales, appearing all over the body, and its getting worse.

i have a 130L tank, 3 angel fish, 1 dwarf gourami, 6 rummy nose tetras and 2 loaches. the plants are wisteria, baby tears, amozon sword, anubias gracias and some moss and drift wood.  28 deg, ph about 7.2. i can't seem to get it lower than this, i've tried, the best i get is close to 7 but then it always returns to 7.2

The loaches were the last additions to the tank initially to get rid of a snail infestation, which seems to have worked, i don't see any snails.

For a long time the anubias had brown spots on the leaves and for the last few months all the fish would get large bellies so i treat the tank from time to time with a small dose of tri-sulfa and I feed the fish either frozen brine, frozen peas and flakes, i alternate. i have removed the carbon from the filter permanently and use phospherous based cotton material. I have noticed recently the rocks in the tanks have acquired a slight green discolouration, the colour of this phosphorous material.

For about a month, this seemed to work well. The anubias no longer has brown spots and looks healthy and great. When the fish would  get swollen bellies, i would feed them brine and a small dose of tri-sulfa and their bellies would return to normal.

About 2 weeks ago, i noticed another change. the anubias started to get a yellow tinge to her leaves and 2 of the angel fish developed open wound sores. I let this go for a week following the same tri-sulfa treatment i had adopted but the sores got larger. so for the last 4 days i've been giving them daily a 2/3 dose of a general fish disease medicine, active ingredient Cajeput oil.

The sores are getting larger! and the anubias more yellow! and yesterday i noticed the loaches are nipping the tetras to the point of tearing their dorsal fins.

I feel like my aquarium is chaos!

Firstly, what is wrong with my angels and how do i treat them please?

Secondly, and i hate to think, should i reintroduce snails in the tank to distract them from chasing the tetras?

thank you kindly for all the advice you can give me.

Heb

ANSWER: Hi Heb,
I would like you to check your water for ammonia, nitrites, and nitrates.  Often when fish get sick, or have sores it is because the ammonia level is high.  This is called ammonia burn.  Please check this first.  Also, I don't know what kind of loaches you have, but some do attack other fish, and this is stressful to fish, and they will get sick.  Once a fish begins to chase other fish, they do not stop.
Since your plant is dying, it would indicate that your water chemistry is off.  Remove the plant, decaying plants will harm your water chemistry.
Write back to me if this is not the case, but I would think that your water chemistry has something to do with this.
Lynda

---------- FOLLOW-UP ----------

QUESTION: Hi Lynda,
thank you for your reply. I've tested the water chemistry, here are the results
ammonia 0ppm
nitrite 0ppm
nitrate 10ppm
ph 7.6 - surprisingly high today. i've added solution to bring this down. what would cause the ph to jump like that?

also, the angel are not improving but not getting worse, they still have open sores on their scales. The loaches are clown loaches.

anticipating your advice.

thank you kindly,
Heb

Answer
Hi Heb,
Angels that have sores is usually due to stress, or they have been injured through fighting, or they have hurt themselves on something pointy in the tank.  Your PH is much to high for Angel fish.  Never you chemicals to bring down the PH.  They do more harm than good, as this will bring your PH down too quickly, and shoot it back up.  Fluctuating PH is very bad for fish.  Driftwood added to your tank will help bring the PH down.  Check if you have anything in your tank that would cause your PH to go up.  Seashells, or coral will bring up the PH.  Angels living in a high PH will stress them.  They should be in 6.5 to 7.0 PH.  It is very important to fish, that they be in the right PH.  We cannot acclimate fish that should be in acidic water to alkaline water, and vice versa.  It is like giving them a headache for the rest of their lives.
Another thing that may have happened is that maybe you have two Angels that tried to form a couple.  If they are not of equal force, the stronger one will try to kill the weaker one.  It is lots of observation to see what is happening.  
Bring your temperature up to 82 degrees, and treat them with Tetracycline.  Remove the carbon in your filter, and follow the directions on the package.  
Watch very carefully what is going on in your tank.  Clown loaches usually do not chase other fish when they are kept in groups.  Even when they are two, they usually play with each other.  They too need a lower PH.  Change 25% of your water, and add one teaspoon per 5 gallons of diluted aquarium salt.  Do not wait to medicate, since the sores will be much harder to cure if they get big.
I hope this will help.
Lynda