Backyard Aquaponics
A place to discuss aquaponics

How can you avoid the growbed to empty the fish tank?
This is my idea. What do you think about this?

How big is your fish tank and how big is your grow beds?

a) in a typical 1 to 1 ft to grow bed ratio, you will not use all the fish tank water because the media in the grow beds use up a lot of space.

b) Get a bigger fish tank

c) you can add a sump tank.

Also, i dont understand how your design keeps the fish tank from draining any more or less than filling all of the grow beds? There's still a chance eventually that all of the grow beds fill at the same time.

option d) you can run 1 or more of your grow beds at constant flood

e) you can cascade your grow beds so when one flushes it fills and flushes the next and the next.. so all of them will never be full at the same time.

bcotton's right, I don't think the idea will work.

Are you draining by siphons and if so are you pumping continuously? If you are just switch one or two beds to Constant Flood by removing the siphon and getting rid of the weep hole in the standpipe. You'll have to add water to compensate for the new holding capacity of the growbeds that are CF but these beds will no longer cause fluctuations in your fish tank (except due to evaporation of course).

Hope this makes sense.

Are the GBs 30m, 20m and 10m long or wide?

Use an indexing valve.

I think you might have problems getting the siphon to start with this design.