Who Gives A Fish Forums

I've been tweaking my Discus tank's flow rate for weeks, but they still seem stressed. Running a 75-gallon with a Fluval FX6, sand substrate, and driftwood. Water's at 84°F, pH 6.8, 0 ammonia, 0 nitrite, 10 nitrate. How do you balance flow without freaking them out?

FX6's a beast for a 75. I'd dial it down to 50% output, maybe add a spray bar to diffuse the flow. My wild-caught Discus chill at 200 gph in a 90-gallon, but domestics can handle more. What's their behavior like near the outflow?

yo, my dudes hate strong flow too. i run a sponge filter plus a tiny powerhead pointed at the glass. keeps the water movin' but no whirlpool vibes. try that, or they'll ghost you like my last pair did.

taieta wrote: ↑Wed Aug 06, 2025 8:16 am FX6's a beast for a 75. I'd dial it down to 50% output, maybe add a spray bar to diffuse the flow. My wild-caught Discus chill at 200 gph in a 90-gallon, but domestics can handle more. What's their behavior like near the outflow?

Agreed on the spray bar. Mine stopped hiding after I added one. Also, check if they're eating near the flow—mine refused until I redirected it.

Slow flow's key for juveniles. I keep mine at 150 gph in a 55-gallon with floating plants to break surface agitation. They're less skittish since I added Valisneria. How old are yours?

My tank's similar—75-gallon, FX4. I angled the output upward and added a pre-filter sponge. Nitrates dropped to 5ppm, and they're way more active. Maybe tweak the direction before cutting flow entirely?

Had this same drama last month. Turned out my flow was fine, but the CO2 diffuser was too close to the intake. Moved it, and now they're golden. Weird how tiny things mess with them.

Thanks for the tips! Gonna try the spray bar and angle adjustments. They're about 6 months old, Lumina, and yeah, they bolt if the flow's too direct. Appreciate the help.

Swiftsea wrote: ↑Wed Aug 06, 2025 11:07 am My tank's similar—75-gallon, FX4. I angled the output upward and added a pre-filter sponge. Nitrates dropped to 5ppm, and they're way more active. Maybe tweak the direction before cutting flow entirely?

Solid point. Redirecting flow can prevent dead zones without stressing them. I'd still monitor their gill movement—if it's rapid, dial it back.

bruh, just saw mine doing the zoomies after i added the powerhead. guess they're cool with it now. trial and error, my dudes.