discus tank ph crash recovery

Chat about all things related to Discus, from purchasing to breeding and everything in between. One of the most beautiful species in the hobby
Dock
Posts: 4
Joined: Sat Oct 01, 2022 9:06 pm

discus tank ph crash recovery

Post by Dock »

My tank's pH crashed overnight from 6.8 to 5.2, and my Discus are stressed. Running a 75-gallon with sand substrate, planted, and a Fluval FX6. Did a 50% water change, but they're still hiding. Any quick fixes?
User avatar
3monkeys
Posts: 7
Joined: Tue Mar 12, 2024 9:40 am

Re: discus tank ph crash recovery

Post by 3monkeys »

First, test your KH. If it's below 2, that's the culprit. Add crushed coral in a media bag to your filter to stabilize it. Also, check your CO2 levels if you're running injected. How often do you water change?
User avatar
guyah
Posts: 5
Joined: Wed Oct 09, 2024 4:40 pm

Re: discus tank ph crash recovery

Post by guyah »

3monkeys wrote: Sat May 03, 2025 12:18 pm First, test your KH. If it's below 2, that's the culprit. Add crushed coral in a media bag to your filter to stabilize it. Also, check your CO2 levels if you're running injected. How often do you water change?
Yep, crushed coral is a lifesaver. I'd also cut back on CO2 if you're blasting it. What's your lighting schedule? Too much light can mess with plants and CO2 balance.
Lion
Posts: 2
Joined: Wed Aug 14, 2024 2:24 am

Re: discus tank ph crash recovery

Post by Lion »

Had this happen last year. My tap water's KH was sketchy low. Started mixing in RO with a remineralizer, and problem solved. What's your tap KH?
Dock
Posts: 4
Joined: Sat Oct 01, 2022 9:06 pm

Re: discus tank ph crash recovery

Post by Dock »

Thanks, all. Tap KH is 1, so that's probably it. Gonna grab some coral today. They're perking up after the water change, but still not eating.
Ticgo
Posts: 11
Joined: Thu Oct 10, 2024 3:33 pm

Re: discus tank ph crash recovery

Post by Ticgo »

Glad they're improving! Try offering live blackworms if they're refusing pellets. Mine go nuts for 'em after stress. Also, dim the lights for a bit—helps 'em chill.
Fuegoz
Posts: 3
Joined: Thu Oct 10, 2024 3:42 pm

Re: discus tank ph crash recovery

Post by Fuegoz »

Yo, same thing happened to my crew. Crushed coral fixed it in like two days. Also, check your filter media—sometimes it goes acidic if you don't rinse it enough.
User avatar
Lyn
Posts: 6
Joined: Sat May 07, 2022 5:00 am

Re: discus tank ph crash recovery

Post by Lyn »

Fuegoz wrote: Sat May 03, 2025 6:03 pm Yo, same thing happened to my crew. Crushed coral fixed it in like two days. Also, check your filter media—sometimes it goes acidic if you don't rinse it enough.
For real. My FX6 was a pH killer till I rinsed the sponges weekly. How old's your media?
Jester
Posts: 3
Joined: Thu Oct 10, 2024 6:03 pm

Re: discus tank ph crash recovery

Post by Jester »

Monitor the pH daily now. If it swings again, consider a buffering substrate like ADA Amazonia. It's pricey but keeps things stable.
Lionheart
Posts: 4
Joined: Thu Oct 27, 2022 4:53 pm

Re: discus tank ph crash recovery

Post by Lionheart »

Agree with the coral advice. Also, avoid overfeeding while they recover. Excess food can lower pH further.
Post Reply