Backyard Aquaponics
A place to discuss aquaponics

Please advise,

My bell siphons aren't starting, my riser pipe is 50mm and my bell is 110mm. The water gets to the right height then just runs over, my thinking is that the 50mm pipes are too big and I'll need to reduce it but that itself comes with a plague of problems as the plumbing is cast into my system, so if I cut the riser pipe I need to know 100% that it is going to work, the only other solution I see is increasing the water flow which comes with its own set of problems as the water is gravity fed from the fish tank and can only come at a certain pace, so the only way I see to alter this is to divide my pumps outlet (which comes from the sump) into the flood and drain beds and I'm not too sure how this will affect the performance of the pump. Please also advise if there are other siphons you think I should try which won't need too much system adjustment.

As you will probably get from others standpipes for bell siphon are commonly 20-25mm depending on growbeds size and system etc. I learnt the hard way also after buying a grow bed with 40mm hole for plumbing- I reduced the standpipe to 20mm for my 500L growbed and it worked well. Increasing the flow will speed up the filling time for your GB also not allowing the oxygen time between for your bacteria etc.


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You can also switch to Constant Flood and just not use siphons. This is an option that many people here use when they want to expand their systems and don't want to get a larger sump tank. Basically in CF the grow beds retain water if the power goes out (so there is no weep hole near the bottom of the standpipe). All you'd need to do is switch to a standpipe without a weep hole and remove the bell from over the standpipe. Water will just flow over the top of the standpipe so this sets the water depth in the grow beds. See "BYAP Trials" thread if you have questions about how well this works.

Just noticed that your plumbing is cast into the system - you've got some leeway as far as the water depth (surface shouldn't stay wet, usually water is about 1.5 to 2 inches below the surface). If you cut the plumbing too short is there room to put a connector with a short length of pipe on the stub - I change the water level occasionally and this is how I do it (I occasionally like to seed the surface of a grow bed so I'll raise the water depth temporarily, to make the seeds stick to the moist media a bit higher up)