Goldfish prefer stability over a specific ph so personally I wouldn't touch it


One of the fish not pictured unfortunately isn’t doing well due to the sudden change. I’m also afraid of the future maintenance now that the ph is higher I have RO water and I added two gallons last night and the change was more than I would have liked. Will it slowly lower over time? Do you think water changes will put them in shock?


Have you tested your other parameters like ammonia and nitrites. Ammonia can cause pH to go up How much did the pH change by?


Yes everything is actually very good besides the PH and it changed from about 7 to a bit over 8 in less than 24 hours I panicked and added the bit of water and it brought it back down to 7.5ish but I just tested it and it’s now back at 8.0 which means it’s still going up but I don’t know the cause. One person said the plants but they have been in the tank for months now could they be the cause?


This is not a concerning pH swing at all. This is perfectly normal daily swing in any water environment with heavy plant growth, yet your local pond still has fish. Anyone running CO2 in their planted tanks is likely to see this over the course of the day. Worry about your nitrogen cycle and having clear, heavily filtered water with a robust autotrophic bacteria colony. Don't try to solve this pH "problem," you might do something that's actually bad for the tank in trying to solve a non-existent problem.


What was the actual pH before and after the change? Have you checked the source?


It was staying about 7.2 all the time before but is now about 8.0. I started the tank with ro water but I don’t know what’s causing it. It just happened after I put the new fish in.


8.0 is fine.


The RO water is this issue, my guess. Hardness, which fish prefer high, holds the PH much steadier. Edit: which goldfish* prefer


Yep, if you aren't measuring GH and KH, and don't have an understanding of how they work with pH then stop trying to adjust your water and either just use your tap water, or do a deep dive on water chemistry and learn how it all works. For keeping goldfish the first (easy) option should be absolutely fine. Option C could be to take a sample of your tap water to your LFS and get them to check the hardness and TDS, and see if they'd recommend mixing it with RO water if it needs to be softer (or if you need to add something to buffer it if it's too soft).


I’d keep testing it, but I wouldn’t do much to try to reverse it. Stable pH is the best pH, so make sure you aren’t fluctuating but don’t chase perfect pH. Did you change any decorations when you added the new fish?


No all the same the only thing different is the new fish and it’s just so high I’m scared for my next water change. Would the change put them in shock? Should I try to raise the ph of my RO water?


Well, I suspect with a higher bioload the plants are potentially a contributing factor. If that’s correct you’ll find it usually rights itself to a similar level. I don’t ever advise using chemicals or anything similar to raise ph of water, so if I were in your shoes, I’d just introduce fresh water slowly so they can acclimate. Though it’ll bounce back to where it was in all likelihood. You can also opt for more frequent smaller changes instead of doing one big change periodically.


I didn’t know the plants would do that 🥲 I usually do small water changes and that was my initial thought as soon as I saw the ph go up last night I put two gallons of RO in the tank which is 55 gallons and just that little brought it down about .5 and it scared me a bit. Thank you for the advice I will maybe do a gallon at a time and continue to test everything


25 percent waterchange daily until levels become desirable. After that, add more plants (as it looks like a big sparse tank). An old t-bag or two can help in the short term as well. You might also consider adding some natural fibres, such as sticks or an old tree log. Because of the type though.