newdreamz - How are the discus and angels doing?
Cerianthis - pH 7.5 is not a high ph for keeping tank raised discus.
Yes it can be. Not all discus are spawned and raised at high pH/hard water.
I bet those breeders who claims to raise/pawn in high pH/hard water are not telling the whole thing. More losses you have, more sales, IMO.
It certainly also depends on each individual keeper too.
Depending on locality, most Discus can be from farms in SE Asia (LOT Cheaper than local bred, for example Half Dollar size pidgeon/turq went for $10 -$15 retail locally). These Discus are not spawned and raised in extreme water since their local water is pretty close to ideal conditions.
Have you ever tried to keep Discus at 7.5? How many and for how long?
Someone keeping few discus/spawning at pH of 7.6 succefully does not necessarilly mean all Discus can sustain their longevity/health in such extreme water. This is due to fact that factors which can contribute to success and failures are too dependent on each individual keeper.
Have you made any comaparison b/n many discus kept at different types of water?
I have done many experiments to understand their ability to adapt water that is not so ideal condition for them.
Kept and spawned many discus in many different water, including wild green/brown/heckel discus.
What I learn form all these trials I ran is that although some Discus can be sustained in such extreme, but their longevity are comprimised drastically.
I also realized that amt of offspring produced at extreme conditions were not as many with high rate of deformity. Well, at least from few (meaning over thousands of discus) trials I ran to my best recollection.
I knew breeders of other regions where their water were not so ideal. They have ran similar trials (in order to reduce the cost/time of preparing ideal condition) but to derived with same conclusion as I have.
"Healthier Fish in Ideal Condition"
I also understand the difficulties in altering water chemistry for most hobbyist but in this case simple 30 G plastic container, heater and small powerhead with bag of peat from garden center should do. Have this reserve running 24/7/365. (I would have reserve running for any fish tank personally). Full time Reserve can save someone's nightmare!
Especially, water which does not contain chloramine, I would get rid of any dechlorinators and have the cost of such additives diverted to running reserve. For one, I have not used any dechlorinator for few decades ever since I learned how to do it and using age water derived better results or should I say less mishaps than using tap+dechlorinator.
As many literatures have stated,
most diseases are stress related. Keeping Discus in such high pH does pose such stress, IMO.
Just trying to share my thoughts for suffering fish.
BTW, OP! DOnt change water chemistry yet!
Sudden changes (even from bad to good) at this point can cause further stress on fish.