Need some adv

[Piraya]

Good Morning,
I have read quite a few post in the forum when I have time. Soon I will move into a new house, so I put my 6 wild discus from the aquarium of 700L into an aquarium of 240L temporarily.
Every day i change about 6L to 12L of water to remove the waste they produce. I have read in several posts that some people changes 50% of water per day and I wonder if i have been changing enough water per day???
Another thing is my tap water comes out with an ph of 7.8 and when i do my daily water change the pH rises slightly to 6.6 and then gradually falls off to 6.0 and the next day when i do the water change the ph raises to 6.6 again and falls to 6.0 in 24H. I can check this because i have a controller of ph..... wich is accurate......
Read a post on breathing discus lowering the pH of the water will breathing ... should this be the reason wy my ph lowers so much? I'm afraid these oscillations harm the fish.
Try to do some tests of my water to give some details...
Fish look great and been fine for more than a month in these conditions....

[pcsb23]

The pH variation is nothing at all to worry over at all.

I'd be tempted to change a little more water but provided you have a properly working filter you should be ok until they are back in their new home. Do watch them though and any sign of things changing increase your water changes and if necessary post on here and we'll try and help.

[DISCUS STU]

Usually rising ph is much less, or not at all, as important as sudden ph crashes downward. With a relatively low ph of 6.0 at times I'd be more concerned with ph crashes, which I've had at times. The answer for that is water changes and sometimes some baking soda to raise the ph. Yes, cardon dioxide from fish respiration as well as other waste lowers the ph.

Gradual ph decreases aren't too bad unless their in the low 5's and lower, sudden ph increases also seem not to be much of an issue.

[Piraya]

Thks, going to feed them now and do a water change after.