The tank size shown was custom built only to allow it to sit in front of my reef tank's sump, any sized tank could be used of course, but I have found that by keeping them narrow and the compartments somewhat small, it has far more benefits than any downside, such as keeping the copepod density high enough for the larvae to have a chance at them. In a larger compartment, it would of course take a great deal more food to reach the same concentrations. It also makes daily partial water changes a breeze as it only takes a quart or two, and by having a pump compartment, such water changes are also safe for the larvae. The only downside I have seen is that you do have to keep up with the water changes, but imagine that would be an issue regardless of the tank size used.
No shrimp settlement yet, just started this project and as I go along, am putting together what I hope will be a one stop harlequin care and breeding webpage. Am learning a lot though, because what little info there is about them online, has so far proven to be wrong. They are very unlike other shrimp species/larvae. They also eat A LOT!!! I just loaded their section with copepods two days ago and I have to go jump into the ocean yet again to catch more, in fact, I gotta go!...lol
Will be glad to answer any questions though from what I have learned so far if you or anyone else gives it a go, but fair warning, its not for the faint hearted, and expect to fail quite often. One tip though, which should apply to most shrimp species, get the "cyclops" copepods, they stay up in the water available to the larvae, the glass crawling pods are useless as the larvae either ignore them, or have trouble yanking them off of the glass. And make sure you have TONS of copepods before hand...lol (brine shrimp is all but useless and can even cause very high losses, according to a recent study) Pods, is the way to go.
Forgot to add that I do not use any lights over the Kreisel, it just attracts the larvae to the suface and have the back and one side painted black to block the light, what light does get to them comes from the pod section which has an added benefit of drawing the larvae away from the mesh screen side of the kreisel. They are going to go to any light source no matter what, and figured I might as well take advantage of it.
The Cyclopoida species that I can catch by the thousands as they swarm in the kelp beds.
One more image, then I really gotta go!...lol This is a shot of the kreisel at day one, had to use the flash on the camera because of the dark background and it made the larvae's eyes shine but also brought out the pods as well, shows the size comparasion well though.
Chuck