How much flow is too much?

[cynicechoes]

Ok, if you don't already know, I have a 24g aquapod that hasjust finished cycling and we just got some new equipment...

We replaced the stock pump with a maxijet 900 and also purchased a Hydor Korallia 1... when we plugged in the Korallia the pods on the walls of the tank got blown around quite a bit, so we unplugged it worried that it might be too much flow... What do you guys think? How should I judge what is enough and what is too much? This is one thing that I really know practically nothing about aside from the fact that its important, so any info you could offer would really be appreciated!

Also, we just got our CUC and in it we have 2 nassarius snails... i noticed when we put them in they buried like theyre supposed to but had the little thing sticking up out of the sand like a snorkel or something... will they always do this? If they die how would I know...

Oh, also, just wanted to double check, what is the ideal temperature that everyone recommends for a reef tank w/ inverts? We are still working on a temp control problem and I just wanted to double check the info that I already have.

Thanks in advance, happy reefing!

[Anselth]

Well, I think the korallia 1 is in the neighborhood of 400gph. right there you're looking at about 18x your tank's volume in flow. Since you generally want 10-20x depending on the corals you want to keep, something that powerful is probably overkill, even if you want 20x, you don't want it all from one source.

[Anselth]

And yes, the Nassarius will always have that "snorkel" above the sand. You'll know if one dies when all the snorkels converge in one spot.

Temp wise, I aim for 79-80 degrees. One of the benefits of a controller is you can pinpoint your temp quite a bit.

[DrHank]

The real trick with a korallia is how to direct it. You will need to try different placements until you find the one you like. Bounce it off the glass on the front try shooting it at a corner. Think about bank shots in pool. Use an air pump and air stone to see where the current is going. Yes, it produces a lot of flow and it takes a bit of playing to find the sweet spot but once you have it you'll love it.

Remember too that it's a propeller and not impeller so you will get a much wider area of flow than with a powerhead. I also have some ideas on how to mod it to reduce flow but maintain pattern. Haven't tried it but it should work. PM me if you're interested.

[Frankie]

You could split the flow with a SCWD SCWD—Squid—Wavemaker
and create a more random flow in a tank that small.

[cheeks69]

The SCWD is a great idea !
I would definitely recommend you get two smaller ph's than have most of the flow coming from one source, you'll get laminar flow you want a more chaotic type of flow that can be accomplished thu the SCWD, wave timer or ph's bouncing flow off of each other.

[DrHank]

Robert, I don't know how familiar you are with the Korallia pumps. I've had my pump 3 for about a year now and I can tell you that properly positioned you will not get laminar flow. The key with a single pump is where you position it and where you direct the output.

Casey & Cody, the korallia pump produces a wash very similar to a boat propeller. An impeller produces a flow similar to a jet drive unit on a boat. The powerheads are highly directional and people either alternate them with a switching device, or point two at each other to break up the flow.

A single powerhead, regardless of where it is aimed is likely to produce laminar flow. Due to the conical nature of the korallia it isn't.

Also, from what I've heard the gears in the SCWD tend to foul, and the unit ceases to function, unless the unit is removed and vinegar is run through it on a regular basis. Robert probably knows more on this subject than I do as I've never used a SCWD.

[Frankie]

Everyone i know that owns a SCWD says great things about them. There are no gears in it. Its a flapper that flaps back and forth changing the flow direction randomly. For the kind of flow their running in that small tank i think it is a good idea. For a tank like mine with a 3000 gallon CL pump you need a motorized ball valve or an oceans motions set up if your trying to divert the flow and randomize.

[DrHank]

Although I'm a big fan of Korallia's I did find some positive comments on the SCWD.

Reef Central Online Community

and in all fairness, I thought I'd post the link.

[kathywithbirds]

If your domino damsel can't swim forward at all, it might be too much flow. : )

[Rcpilot]

My tank is a 30g tall.

I have a total of 1100GPH in my tank.

The Maxijet 1200 is 295GPH and thats going through my refugium.

There is a 300GPH powerhead down low in the back corner on each side. Those two spray across the back wall and are directed right at each other. There is a LOT of rock stacked against the back wall, so I'm sure that it's not ripping through there. Lots of obstructions to break it up.

There are two powerheads on the top of the back wall and they point directly out and towards the front of the tank. Those are about 110GPH each. They produce a small boil in the surface of the water. I'm hoping this will help with oxygenation by creating lots of surface disruption.

That's over 36x per hour.

My tank looks totally calm to me. My mushrooms aren't blowing around like crazy. They barely move. My zoas aren't bent over like trees in a hurricane. The outer edges just kinda sway around a bit.

I think a lot of it is because I have 61lbs of rock stacked into a 24x24x12 tank. The rocks break up the flow a lot. I'm going for random/turbulent flow. I don't want all of the heads pointing in one direction and creating a toilet bowl effect. Seams to be working.

IMO, you can't put a specific number on GPH. Just like you can't say exactly that it takes 27 days to cycle a tank. Some take 6 weeks. Some take 5 days. Some say 1" of fish per 5g and others say 1" per 2g. Depends on a lot of other factors. Each tank is individual and unique and will have different flow requirements.

I'd say to follow the advice given so far. Bounce the Koralia off a corner or blow it at a large rock and let that rock break up the flow and create turbulance to disrupt the direct flow. Maybe set a rock 6" or 10" out in front of the Koralia? Or point the Koralia at a corner and then put a rock 4" out to disrupt the flow after it bounces out of the corner. There will be calm areas behind those large rocks or obstructions. You can place livestock (zoas) behind those rocks. The high velocity flow with go right around them.

[cynicechoes]

Ok so here's the deal... we tried a couple of different positions with the Korallia, putting it in a back corner and aiming it at the front glass, pointing it at the rocks, and at a corner, the same thing seems to happen... I see pods flying all over the tank in completely random patterns, as well as being sucked in and chopped to pieces and blown out the front! lol It doesnt seem to matter where I place it I get the same effect, that is why I am thinking it might be too much for the tank... I don't have any coral or anything to judge off of how much its getting blown around at this point, so I really dont know!

[prow]

sounds more like too many pods not too much water flow. to see the currents in the tank just slice a couple slits in a plasitc straw and wedge it inbetween a couple peices of rock. it will give a decent idea on the velocity and turbulance in the tank.

[Melanie]

Casey, I just noticed HK has a "nano" powerhead. It is HALF the power of the HK1. http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=15955&Ntt=hydor%20koralia& Ntk=All&Ntx=mode+matchallpartial&Np=1&pc=1&N=0&Nty =1

Maybe you can see if you can trade in your HK1?

I haven't used the SCWD so I can't say if I like it or not, but I have used a powersweep powerhead (which also rotates) and it always gets jammed. It has a strong stream that I can't diffuse enough even with the parts that are supposed to make it diffuse. (maybe irrelevant.)

[Melanie]

On the temp thing...I keep mine at 78 constantly but I seriously consider upping it to 80. I'm in the research stage right now.