Strong flow

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Redpanda
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Strong flow

Post by Redpanda »

I’m using Fluval fx4 for this tank. And initially was really worried flow was super strong, plants swaying and all that. So I adjusted the nozzles to the glass so it breaks the flow quite a lot. It was fine for a while then I started getting diatoms and green spot algae and in general the surface had dead spots for movement ( I thought) . So been readjusting nozzles trying different positions. I think it cleared a lot of dead spots and diatoms and water brightened up I thought.
Couple of concerns now that the flow is really strong and directed across the tank:

1. Will it harm the fish? They all seem to be fine and enjoying it, tetras and Corys surfing the flow a lot, Bolivian rams aren’t that bothered at the bottom of tank, and Angel fish looks fine but read that they like slow flow. So my concern, even if fish seem fine, would it actually bother them long term of naturally they used to slow rivers and stuff 🙈

2. My plants never do well, some of them die and some of them OK now that I’m dosing daily with ferts and liquid carbon. they aren’t thriving. Amazons going Lacey, vallis doing ok just, others melting leaves too. Could be to do with soft water or low KH, but maybe wonder if some of them will not like strong flow neither.

So how to know when it’s ok flow or not?

SxAqua
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Re: Strong flow

Post by SxAqua »

I think a starting point is how big is the tank? I don't think I'll be able to help but there's plenty on here who will be using the fx4 👍

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PaulVerrall
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Re: Strong flow

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Redpanda
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Re: Strong flow

Post by Redpanda »

So the tank is only 90x50x60cm

I personally like stronger flow and prefer to be changing nozzles about every week or so to ensure there are no dead spots for long periods of time and they’d change at least..

The only worry is if , with my limited knowledge, I’ll be causing harm to fish and/or plants long term ?

Might consider spray bars if better for fish

AshLawson
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Re: Strong flow

Post by AshLawson »

I’ve got 2 U4’s in a 100x45x50. I have one firing across the top rear from right to left with the Venturi on to get surface agitation and air bubbles, the flow points straight at the other u4 in the opposite corner which vents from the middle/bottom and is angled against the glass. I ended up attaching a large set of roots to the back infront of the first filter to interrupt the flow a bit and slow things down. Combined with the planting i now have an anti-clockwise flow from top right, across the back, down the left and back across the front. It gives everyone the options to sit in the current, find a sheltered spot, or hide altogether. By tweaking the placement of the wood infront of filter 1 it helps to control the flow. It’s early days but I’m going to leave the dead spots as just that, and on big cleaning days just set the first filter to vent from the bottom for five minutes to blast any loose detritus from behind the plants. It seems to be working for my lot anyway. Hope that might give you some ideas!
200l 1000x500 planted Amazonian, 24 x Paracheirodon innesi, 10 x Hyphessobrycon megalopterus, 6 x Corydoras Sterbai, 1 x BNP. Still to add a pair of Angels
2 x Fluval U4 internal

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