Which is more critical high to low or low to high PH acclimation?

I cant seem to get an answer on the internet on this but I suspect that PH shock is more critical when going from a full point lower PH to higher PH as this seems to be the classic scenario with high nitrate low PH, to water change with higher PH and lower nitrates. It seems that going the other way high to low PH is more forgiving as I have made this mistake in the past and noticed no ill affects and just wondering if someone can confirm this. Not that it is of any monumental importance but knowing one is deadlier then the other seems to be an important thing to know and an interesting issue.

msjinkzd said:

i am not sure that one is more critical than the other though in a higher pH things like ammonia become much more toxic so fi doing a gradual acclimation in shipping water containing ammonia, this can cause issues for the fish.

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Oh that's right, NH3 becomes more present when PH rises especially above PH 8 it really becomes toxic when ammonia is present, forgot. Thanks

Is high TDS related to high Phosphates? I notice my older tanks have high Phosphates 10+ PPM and Cal/mag hardness of about 71 PPM (PH7.4) while my untreated tap water has almost 0 phosphates and 606 PPM of Cal/Mag hardness, KH 143, PH 8. My inside house and aqua source water is now softener treated using potassium and comes out 143 KH and 36 PPM Cal/Mag, KH 143 (unchanged), PH 7.8. Since I have switched to softened water ( I like to use the word filtered) although my fish are generally healthier (fin rot much less prevalent), I notice they get stress if my water changes exceed 30%.
I recently lost some fish with a out of the norm 50% water change and wondering if high phosphates to low makes a hazard difference. I do treat the water for PH difference and make sure it matches my 7.4 aquarium as it go's in, so the only major difference in my aquarium to source water is the phosphates going from 10 PPM to 1 PPM source water and hardness going from 71 Cal/Mag to 36 Cal/Mag source, and PH from 7.4 to 7.8 source, KH is 107 to 143 source. See any water change issues here. Although I have only recently been make an attempt thoroughly test my waters, I still don’t understand their relationship with water changes with respect to this TDS thing.

Unfortunatly RO is no longer an option at the rate I was using it, as it is I use it for evaporation top off and chem mixing when necessary. The potassium trade off is 300 mg/l or 300 PPM. The trade off is not 1 for 1 because I have my softer set to miser mode and sensors will not allow potassium to exceed 300 PPM. I do have a planted tank of sorts as I grow low light English Ivy (hedra) out of my HOB filter voids hydroponically, once growing fast nitrates drop dramatically. Since I got my softener off salt they are back and growing with the potassium and nitrates are finally falling from 20 PPM to 10 and hopefully on the way back to 5 and 0 like before. Anyway thank you for your insight into TDS, KH and GH. Ill make sure to remember what you have pointed out to me, very good stuff I needed to know. Thanks.

I had to do some more reading to understand TDS but the light switch finally went on and yes even with 606 PPM of Cal/Mag being softened to 35 PPM I still am probubly very high in total TDS, at least that is what I read even from the softener manufacturers. Yet my fish seem so much more at ease, to be sure I will have to get a potassium tester, hopefully my plants are removing some of it. Also summer time here in AZ the well water tanks get hot and cold water is 90F, even 30% water chnages like the one I did yesterday in my 60 tank raised the temperature to 84F this coupled with tap water already having a low oxygen content, dechlorinator removing even more oxygen, really makes summertime water changes here a potential hazard. I am going to have to start premixing my water in a 55 gallon plastic drum and aerate overnight to get the OX up and temp down otherwise im going to loose more fish. For now I am once again adding 15% RO to the mix. Thanks again CarlTh, you got me on the right track.