i did a search and the topic is sparsely covered.
in the marine world a 10 factor is standard.
i have heard that divers in the lake deal with a strong current.
i am working with a 180 gallon and 2200 gph or 8800 lph in combo with a sump.
the fish mostly stay around the perimeter where the flow is strongest.

your thoughts.
thx dave

Sounds more than sufficient. I have a 180 with Petros, and im running about 10 times turnover through filtration, and 4800 gph in powerheads.

I am almost finished setting up my tank now... converting from Reef to Tropheus... 150g display tank and 110g sump... Baracuda return pump (about 3000g/h @ 10' head pressure) and 2 Tunze 6055's in the display tank ( about 1450 g/h each ). About 6000g/h total water movement or approx... 23 X turnover. When I was running my SPS dominated reef tank I had a ton more flow... more like 90 x turnover.

In my petro and troph tank, 200g, I run about 10x turnover with a vortech mp40w. I think what you gents have is plenty. The trophs will be happy in that home and get yourself at least 30 fish.

Hi

I didn't use powerheads/circul;ation pumps until recently relying on big eheims
I bought some Hydor Koralias 5s and 6s - TBH, I'm really not sure the fish are any more active than they were. One does like to try and surf in the output from a Koralia 5 but the others seem to try and avoid it plus, all the fry are hiding

What is the thinking behind this? Given that I've already done it as everyone else seemed to be pumping thousands of gallons and I was feeling left out

In my 150 which is currently houseing 16 Ilangi, soon to be more. I run a 2260 Eheim canister filter, and a over flow / sump that is moveing about 600 gals a hour.I also have a k3 & k4 powerheads that run at set times during the day, just to change things up a bit.

All the outputs of my pumps & filters are directed to the surface because strong movement of the water surface creates oxygen. Pointing them to the centre (of the tank) would just be pumping water.

rgds
gernot

On a 75 gal. tank, I run two AC 110's and a Marineland C360. There are 26 Nkonde Yellows in the tank and they seem to be pretty happy. I guess overall I am turning over about 1350 gals an hour. The important thing is they seem happy and they keep breeding (which makes me happy).

IMO it just doesn't make sense to me to have high flow in a troph tank. When I did SPS in a reef it did to remove debris, circulate food and reduce algae. But in a troph tank, I like it when the crap settles because I am just going to siphon it in a weekly water change (40%). I have no flow other than a sponge filter bubble stream and a hang on filter with carbon.

I see the most hard core Troph keepers/breeders running spong filters only. So I just follow that success. Flow cannot be that important to a troph.

I have a 210 with 120 Ilangi i run a wet & dry filter also have a 2050 eheim with a 1200 gal pump per hour and a 2087 eheim filter. I thing that is a good water flow.