PH Fluctuation

Hello all,

I have fish-less cycled a 75 gallon tank with hopes to fill it with 6 adult discus. Tank has been running about 2.5 months and cycled.
This was a slow process but eventually cycled.

0 ppm ammonia ( goes from 2 ppm to 0 in ~12 hrs)
0 ppm Nitrite ( consistently)
Nitrate ~ 5 ppm (currently after large water change. Was up there near 50-60+ ppm before w/c)

I have change water 5 times during the cycle.

My question relates to PH drop. I have well water and age it in a barrel with air stones & heater.
I use the api master kit so reading the colors is not the most accurate means. what i see is:

Well water has high alkalinity (120-150 ish on a pool test strip)
somewhat low hardness ( lab test myself (chemistry for engineers class) at ~50 ppm carbonate hardness was the test i think but i remember 50 ppm for sure)

H20 out of tap PH ~8.3

Aged water doesn't change much, slightly lowers to ~8.1 PH

What happened after my last two water changes was the PH dropped to 7.8/7.9 overnight less than 12 hrs. It remains at this PH for weeks or until next water change. ( no crashing)

The first two water changes did not change much at all but the tank was still cycling.

I added some manzanita branches around this point. ( im thinking this may be the culprit) but tannin's are not real noticeable any more after a couple w/c's.

Will this change in PH effect discus when i do large water changes? Going from ~7.8 to 8.1 with a big water change and then back to 7.8 overnight? Everything i read states this is not ideal and I do not want to stress the fish.

Maybe i am just overthinking.

Any thoughts would be great. Thanks for your help. Ill do an intro post in the introductions section.

That PH change will most definitely affect your fish and I would like to say that one of my biggest peeves since coming to this forum is that people are told that if your going to keep discus you have to do big water changes, and I hope someone picks up on the point I'm trying to make here the big water change people I think sometimes forget to explain their abilities and Knowledge they have that enables them to do these changes without destroying their water parameters mainly ph I think it's second nature to them I myself do not have the ability or the knowledge so I choose to do smaller more frequent changes while monitoring my parameters mainly amonium and nitrates I would say to ease yourself into the big changes and start by doing the biggest change you can without altering your ph and then speak to a big changer and gain some knowledge from them

Hi Jon, I think you are over thinking this. Discus will handle a ph rise with no issues and it is normal for the ph to fall over time in a tank with a bio-load.
Pat

Yeah Jon, Pat's right - should be no problem - don't worry about it.

Thanks guys. The more i typed this post the more i thought i was overthinking. Mind at ease now.

At least you took the time to confirm!!! :thumbsup: