Who Gives A Fish Forums

My discus tank water has been cloudy for days now, and I'm not sure what's causing it. I've got a 75-gallon tank with six discus, all around 4 inches, and they're acting normal but the water looks milky. I do 30% water changes twice a week, use a Fluval FX6 filter, and feed them a mix of frozen bloodworms and beef heart. Tankmates are just a few cardinal tetras and corydoras. Any ideas what's up?

Sounds like a bacterial bloom, dude. Happened to me last month. How old is the tank? If it's new, it might just need to chill for a bit. My 55-gallon did the same thing after I added a bunch of new plants. Took like a week to clear up.

Lido wrote: ↑Sun Apr 20, 2025 7:40 pm Sounds like a bacterial bloom, dude. Happened to me last month. How old is the tank? If it's new, it might just need to chill for a bit. My 55-gallon did the same thing after I added a bunch of new plants. Took like a week to clear up.

Bacterial blooms are common, but let's rule out other issues. Rayon, what are your water params? Ammonia, nitrite, nitrate levels? Also, how often do you clean the filter media? Overcleaning can mess with the beneficial bacteria.

I had this issue when I overfed my discus. Cut back on the beef heart for a few days and see if it helps. Also, check if your filter flow is strong enough. My FX6 handles my 75-gallon fine, but if it's clogged, it might not be pulling its weight.

Yo, my tank did this weird vibe thing too. Turned out my tap water had some sketchy stuff in it. Started using Seachem Prime and it cleared up. Maybe test your tap water, just in case?

picker wrote: ↑Sun Apr 20, 2025 9:18 pm

Lido wrote: ↑Sun Apr 20, 2025 7:40 pm Sounds like a bacterial bloom, dude. Happened to me last month. How old is the tank? If it's new, it might just need to chill for a bit. My 55-gallon did the same thing after I added a bunch of new plants. Took like a week to clear up.

Bacterial blooms are common, but let's rule out other issues. Rayon, what are your water params? Ammonia, nitrite, nitrate levels? Also, how often do you clean the filter media? Overcleaning can mess with the beneficial bacteria.

Agreed. Cloudy water can be from overfeeding, bacterial bloom, or even substrate dust. Rayon, what substrate are you using? If it's fine sand, it might need more rinsing. Also, how's your lighting schedule? Too much light can fuel algae or bacteria.

Thanks for the tips, everyone. Tank's been running for about 8 months, so not new. Water params are good, 0 ammonia, 0 nitrite, nitrate around 10 ppm. I use CaribSea sand, rinsed it well before adding. Filter media gets rinsed every 3 months in tank water. Gonna try cutting back on food and see if that helps.

Cool, sounds like you're on top of it. If it's not food or params, maybe just give it time. My tank cleared up after I stopped messing with it so much. Sometimes less is more, ya know?

If it persists, consider adding a UV sterilizer. I've had great results with the Green Killing Machine on my 90-gallon. Cleared up a stubborn bloom in 48 hours. Just make sure to remove any chemical filtration while it's running.

picker wrote: ↑Mon Apr 21, 2025 3:56 am If it persists, consider adding a UV sterilizer. I've had great results with the Green Killing Machine on my 90-gallon. Cleared up a stubborn bloom in 48 hours. Just make sure to remove any chemical filtration while it's running.

Second this. UV is a game-changer for cloudy water. Just don't run it all the time, or you'll kill off the good bacteria too.