Too Much/Little Flow?

Wandering Albatross · Aug 1, 2025

Good morning all, I've been playing with flow lately trying to get the best fit, but trying to dial it in for better sps pe has been a pain. There is so much conflicting information as well regarding flow. When I feed pieces drift slowly around the tank, but I worry if the sps are getting enough flow, as if I put my hand down next to them, I don't feel any noticeable water force, but if I spot feed reef roids they drift away. Do I need a lps to be blowing sideways nearby to determine that they have enough flow, or just a lot of drifting movement?

I currently have x2 Maxspect Jump Gyre DC 4000 gph on opposing ends of a 5ft 150g tank. They do not push a straight line of water, they point slightly down, so I turned one upside down to break the surface, and left the other in standard orientation, pointing down towards the rocks. I also have 2 midsize tunze on the back walls, both pointing outwards towards the corners to help with flow under the maxspects. I've tried running both gyres at %100, running the surface at %100 and the other at %50, and now both are running at %50 pulse mode while I observe changes, of which I've seen none on any setting. The only thing flow has seemed to influence is my clam, and my smaller fish getting blown around a little less.

Thoughts?

TX_REEF · Aug 1, 2025

gentle chaotic movement is what you want, not corals getting blasted over like a palm tree in a hurricane. It sounds like you have it right. If you have food that falls and settles onto the rockwork and substrate, that would be an indication to dial flow up.

Are all your corals happy and healthy, with no detritus or algae settling on them? if so, I'd consider your flow duly sorted.

Wandering Albatross · Aug 1, 2025

TX_REEF said:
gentle chaotic movement is what you want, not corals getting blasted over like a palm tree in a hurricane. It sounds like you have it right. If you have food that falls and settles onto the rockwork and substrate, that would be an indication to dial flow up.

Are all your corals happy and healthy, with no detritus or algae settling on them? if so, I'd consider your flow duly sorted.

That's what I've been trying to dial in. I'm battling dinos right now and I'm blowing some corals off daily while this gets fixed. Every so often a spare piece of mysis lands on the plug of one and drifts off after a bit, but keeping the dino strings off them while I break it up for the filter socks to catch has proven to be more of a problem. And keeping dinos from making a stringy mess of the sand.

I hear high flow for sps, especially acros, and I keep thinking of rough waters. I've had 2 slightly undercolored but otherwise fine acros RTN overnight after weeks in the tank, while others are unaffected, and with the exception of a cranky toadstool, all lps are fine. I read that too low flow could cause RTN, then right after someone else said too high flow can cause it..? It's almost like the remaining sps are in a holding pattern. There's been little/no growth, little pe, and the colors of several are dull, yet only a couple have deteriorated overnight. I did have low nutrients that I've recently brought up which might help over time. In my research people have said it can in some cases take weeks or even months to color up picky sps, I just want to make sure I'm doing everything I can to give them what they need to settle in and really take off.