Drastic Ph change help

[RNbowmom]

I need yalls advice. I was quaranteening for about a week some dwarf red gouramis. They all look good but I was about to do a water change when I tested my tap and it has changed from 7.5 for the past three months suddenly to 6.8 way too different. I was considering going ahead and moving them into my main display which is more stable and needs fewer changed. I have a baby rainbow shark in there who hides all day. That tank was also cycled with added ammonia and can process 1.0ppm in 24 hours. My reds usually create a little less than .25 ppm per day. My ruby shark appears healthy but I decided it would be a good idea to treat him preventatively (and also considering possible slow growing internal parasites). The params in the main display are similar but the ammonia in the quarantine tank is rising although it is treated with prime to protect them and quickstart and seeded with water changes from my main display. Its not enough. Ro/di water is so expensive for such a small amount and im noy convinced aging water will help me since whatever cause the ph decrease also comes with a high water hardness (most likely the constant storms we have had over days). If i choose to go ahead and combine them I would makeshift a top bottom divider even though my ruby shark "sleeps" all day in his favorite cave and gouramis huddle together and "sleep" at night. I have six reds and they have cave homes to connect to the glass coming tomorrow. I was hoping for some females but got stuck with six males as I was unable to customize but they said its usually fifty fifty. Yeah no all males. I would like to rehome some of them but everywhere I look they don't allow you to advertise so ideas on that would be helpful too. Theyre all beautiful but I know as they get older will likely be aggressive and I want a few and a bunch of females instead of a bunch of males.

 

[Enchantress]

How quickly the pH will change depends on 1) the amount of water changes and 2) the buffering capacity of the water in your tank (aka the KH). If the KH is high, the pH will remain fairly stable even if you add something that lowers it (it acts as a sort of "sponge" absorbing acids). Distilled water has almost no KH and as such is not a very good idea for fish tanks, as the PH is much less stable in such water. And it's completely devoid of any minerals, so you'd have to supplement (especially if you have plants). Same goes for RO. Not really worth it imho unless there's a good reason for it (i.e. the tap water is completely unusable for some reason). But in your case a pH of 6.8 is still within the acceptable range for both dwarf gouramis and rainbow sharks, so I wouldn't worry too much - especially since it's not like it's going to suddenly drop overnight to that level, the tank has some inertia that should keep it stable or at least soften the blow from the change, so to speak - make it less likely to stress or shock the fish.

But maybe someone else will come along with more knowledge, I'm not an expert.

 

[RNbowmom]

Thank you for your reply. I actually had seen them become more distressed after adding about 1/8 of the water so i dosed prime and held off on it. Three still died unfortunately. One died when the canister filter broke off it fell on him. One had bad ich and I have been waiting a week for medicine and one got in a fight with another and lost. I finally got their little houses in today and the medicine i ordered before I got them has just now come in. The struggle is serious because of the riots there is no medicine. My local stores are empty. I have three left that look in good shape. I was able to successfully age water overnight with an emergency aerator. It expedited removing co2. I was able to match their ph and add water. I will keep changing little by little until tomorrow when I can start the ich x.

Does anyone know what water conditioners can be used alongside ich x. Im aware prime is a bad idea. Im prepared to keep changing water until i get them through the ich x treatment though. These fish are super skiddish. The worst of any i bought its like they were never "handled" like the lights never changed like there was an auto feeder. Idk you cant even walk in the room and they completely panic. The three I have left are unphased though and still look good so I'm sure I can get them through their medicine without them dying. I've also been slowly adjusting temp up to help with the ich. It must not have been very warm in their old home tank. I've got it from 76 to almost 79. I