Seems your sump is 500mm wide, front to back.
Flake test, testing the rate of flow via a sump. You want enough flow so that flakes released just under water at inlet side to travel as far away as possible. It should not settle down immediately below the point where you released it. Do you have any settlement on your DSB at this moment? How is the tanks connected? One or 2 50mm pipes?
I found the water head test to be a better measurement for flow rate. The water level between last divider and actual water surface should be between 6 and 10mm. It does not matter how wide the sump in different systems. If it got the same head height it got the same flow rate.
For a nice head height I calculated a pump delivering 3300 into the tank. That is after head height being taken into account. The pump you got is too small.
But before you go out and buy a bigger pump, just test it first. Add a 1000 to 1500 L/h pump that goes directly back to first chamber for a couple of weeks. That should increase your flow rate.
On the first day, temporary redirect your main return also to the first chamber, going into a filter sock. Just wave above the sand lifting the detritus. It should go to last chamber, pumped by return pump back to first chamber into the filter sock. Just keep an eye on the sock that it does not get too dirty and overflow. This should be a once of job just to get rid of the excess. Then let the sump settle. Redirect main return to display. And thereafter let the system run with the extra pump running water directly to the first chamber.
After a couple of weeks, you should be able to see if this test actually worked. Then you can upgrade your return pump. Only problem is that your overflow is narrower than your sump. Upgrading the return pump will increase the head height in the display. Issues with that are that you will have more water draining when the power goes out. And possible for livestock to flush over. Easily end up with a 5mm rise in the water level in the display. Depending on your system, just keeping the second pump directed to first chamber would be better.
Lastly, are there anything on the sand? Like a piece of live rock or some empty snail shells?
Flake test, testing the rate of flow via a sump. You want enough flow so that flakes released just under water at inlet side to travel as far away as possible. It should not settle down immediately below the point where you released it. Do you have any settlement on your DSB at this moment? How is the tanks connected? One or 2 50mm pipes?
I found the water head test to be a better measurement for flow rate. The water level between last divider and actual water surface should be between 6 and 10mm. It does not matter how wide the sump in different systems. If it got the same head height it got the same flow rate.
For a nice head height I calculated a pump delivering 3300 into the tank. That is after head height being taken into account. The pump you got is too small.
But before you go out and buy a bigger pump, just test it first. Add a 1000 to 1500 L/h pump that goes directly back to first chamber for a couple of weeks. That should increase your flow rate.
On the first day, temporary redirect your main return also to the first chamber, going into a filter sock. Just wave above the sand lifting the detritus. It should go to last chamber, pumped by return pump back to first chamber into the filter sock. Just keep an eye on the sock that it does not get too dirty and overflow. This should be a once of job just to get rid of the excess. Then let the sump settle. Redirect main return to display. And thereafter let the system run with the extra pump running water directly to the first chamber.
After a couple of weeks, you should be able to see if this test actually worked. Then you can upgrade your return pump. Only problem is that your overflow is narrower than your sump. Upgrading the return pump will increase the head height in the display. Issues with that are that you will have more water draining when the power goes out. And possible for livestock to flush over. Easily end up with a 5mm rise in the water level in the display. Depending on your system, just keeping the second pump directed to first chamber would be better.
Lastly, are there anything on the sand? Like a piece of live rock or some empty snail shells?
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