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My breeding tank water keeps getting cloudy a few days after water changes. I've got a 75-gallon tank with six adult Discus, sand substrate, and a Fluval FX4 filter. Temp's at 84°F, pH 6.5, and I do 50% water changes every other day. Feeding beef heart mix twice daily. Any ideas why the water's not staying clear?

Cloudiness could be bacterial blooms from overfeeding. Beef heart's high in protein and can mess with your bio load if you're not careful. Cut back to once daily and see if it clears up. Also, check your filter media, might need a rinse in tank water.

I have same problem but smaller tank. 40 gallons, 4 Discus. Water cloudy after 2 days. Use sponge filter. Maybe need more filtration?

Swiftsea wrote: ↑Fri Sep 12, 2025 6:16 pm Cloudiness could be bacterial blooms from overfeeding. Beef heart's high in protein and can mess with your bio load if you're not careful. Cut back to once daily and see if it clears up. Also, check your filter media, might need a rinse in tank water.

Yep, agree with Swiftsea. Beef heart's messy stuff. Try adding some purigen to your filter, it's a game changer for clarity.

Thanks for the tips. Gonna try cutting back on feeding and check the filter media. Appreciate it!

Your tank's too small for six Discus. That's the issue. Crowding causes waste buildup, no matter how much you clean.

I've had luck with adding more plants. Java fern and anubias help keep water clear. Also, try a UV sterilizer if it's persistent. Works wonders for me in my 55-gallon.

What's your nitrate level? High nitrates can cause cloudiness too. Test it next time it gets hazy.

Haterw wrote: ↑Sat Sep 13, 2025 8:48 am Your tank's too small for six Discus. That's the issue. Crowding causes waste buildup, no matter how much you clean.

Nah, 75 gallons is fine for six if you're on top of maintenance. It's more about the feeding routine, like others said.

I use a canister filter with ceramic media. Never had cloudiness. Maybe upgrade your filtration?