HCA: Hermit Crab Association

After lots of discussion with a fellow crabber (Rizky) I have decided to follow his instructions and build myself a filtered kriesel. I have had lots of babies in 2021 and already 2 spawnings in 2022 some of which I didn't raise as I just did not have capacity. SO this kriesel is vital.

I started with a 60x30x30cm tank and installed internal dividers to make 2 chambers 25cm wide and a central 10cm area. In the bottom of the chambers I put strips of glass at an angle along the bottom edges to create a circular sort of effect. Then the central chamber is sectioned off with some very fine mesh (I used net curtain material)

At this stage I am up to siliconing the mesh to cover the gap. I am very happy with the results so far IF you don't include the very messy silicone job on the glass panels and angles.

This will hold about 45L in 2 chambers and the central filter area. A filter will sit there with a water dispersal rigging to deliver filtered water to 2 spray bars which will create a circular flow in the water. (One on each chamber)
Photos to follow

Sounds awesome.

Will the filtration system allow you to keep the water parameters in the kriesel such that you won't have to pipette the zoea out as often?

First step. The bottom central glass and the two outer angles were done and left to dry a little. The filter will sit in the narrow middle chamber with a riser and spray bars taking the water to the outer chambers where the zoea and mega will be


Second step was adding the inner angle pieces and the small top central pieces. See what I mean about the poor silicone job



This shows the mesh. It is way bigger than it will end up but I will cut it once the silicone dries and then silicone the rest so I can get it tight. This is what allows the water and debris through but not the zoea and mega ( well that’s the plan.


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The larger water volume (6US gallons per chamber) and the filter should help. People who have used this sort of set up say 30% water change every week. That's with 10thousand zoea in a smaller chamber.... Aussies don't produce that many zoea so that will also help. This current batch I'm raising in jars is 1000 and it is a big lot. Plus Aussies only stay in water 12-14 days so perhaps smaller changes more often will work better.

This looks amazing! I hope it helps you out and makes things easier on you.

This is the actual size of the mesh. About 5x30cm


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The finished product. Now to work on the filter and spray bars.




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Nice to see it come together. For the spray bar, are you doing premade or DIY?

All self built. Black 13mm poly pipe for garden irrigation and a couple of 15mm risers for the actual spray bar. I will need to drill holes in them to be the spray bar this bit screws into the t bar across the back and has a screw on end cap. Should make it easier for cleaning.


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The bits and basic set up.


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Assembled now but no holes in spray bars yet Designed to sit on the top edge of the tank but that can be changed if need be. The filter is a variable one which was suggested as it needs to lift the water 30cm then disperse.







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Honestly, if it was me, i would create a slit along the entire length of the spray bar so its even distribution. Im not 100% sure if its been finalised, but just in case, the spraybar needs to be flowing down the mesh so the zoea doesn't get trapped on the mesh.

View 'option 1' - common in delicate or small organism aqua:
https://www.reef2reef.com/threads/kreis ... nt.780835/

Also, ensure the outlet of the filter (spraybar) is underwater, as if its above, it will produce 'micro bubbles' which may cling on to the zoea, impacting their ability to stay suspended 'properly'.

Hi aussieJJDude, Thanks for that information. I will consider it What I've done so far is easily adjustable at very little cost. I've done one close and one away from the mesh. Don't think I can cut a slit in the spray bar. It is solid Plus the pump won't create enough pressure to get the water out of a slit I don't think.

I have a few of those same style internal filters/circulation pumps. They push a lot of water for their size and the black coarse sponge in them lasts forever it seems.

Woah that's so cool!