best discus tank water flow rate

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archibald
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Joined: Sat Sep 16, 2023 10:37 pm

best discus tank water flow rate

Post by archibald »

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?
taieta
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Joined: Fri Mar 29, 2024 7:16 am

Re: best discus tank water flow rate

Post by taieta »

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?
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discups
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Joined: Wed Oct 23, 2024 8:07 am

Re: best discus tank water flow rate

Post by discups »

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.
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jade
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Joined: Thu Jan 13, 2022 4:03 pm

Re: best discus tank water flow rate

Post by jade »

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.
Lumina
Posts: 8
Joined: Thu Oct 10, 2024 6:23 pm

Re: best discus tank water flow rate

Post by Lumina »

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?
Swiftsea
Posts: 22
Joined: Thu Oct 10, 2024 6:16 pm

Re: best discus tank water flow rate

Post by Swiftsea »

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?
metiteh
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Re: best discus tank water flow rate

Post by metiteh »

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.
archibald
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Joined: Sat Sep 16, 2023 10:37 pm

Re: best discus tank water flow rate

Post by archibald »

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.
taieta
Posts: 11
Joined: Fri Mar 29, 2024 7:16 am

Re: best discus tank water flow rate

Post by taieta »

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.
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discups
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Joined: Wed Oct 23, 2024 8:07 am

Re: best discus tank water flow rate

Post by discups »

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