Backyard Aquaponics
A place to discuss aquaponics

Question for all you experienced wise ones out there. My system is up and running great , plants and fish thriving. I have 8 IBC grow beds. However , The auto siphons on a few takes are now not kicking in. Same flow rate , is this possible the roots in the gravel ? Ive got my flow maxed with my pump size and really didn't want to add another.

As long as you've eliminated things like the elbow not pointing slightly down, and other physical things, I dare say the flow isn't enough to kick it off. Are the ones that aren't kicking off further away from the pump? Or higher?

Try turning down the flow on the other beds just slightly with each, and add a little more to the ones that are struggling.

Or run some constant flow.

An increase in volume of roots over time in the GB would have the opposite effect from what you are describing... unless the roots are blocking the inlets in the outer gravel guard on the siphon... have you been rotating the gravel guard regularly to snap off any intruding roots?

It could also be that you are getting less flow from your pump to the GB, the pump may need a thorough clean out. The pipework could also have a build up of bio-film restricting the water flow. Pump output also reduces over time, it may require a new impellor.

I would check the pump screen, lines, pipes and any valves along the outlet side then check the siphon assembly for root infiltration.

On my old system, at the end of the season root infiltration was always an issue. On my new system, throughput is an issue due to pump and line build up.