Backyard Aquaponics
A place to discuss aquaponics

Have been setting this system up for a year now. Fish tank is about 320 Gallons. Sump tank stays about 1/2 to 3/4 full once the grow beds are empty. We just put the fish into the fish tank and started flowing. Here some pictures of system. Then I have a few questions for you. My questions first I can not attach a picture I do not know how. Question one I have a timer that will not let me adjust its on time for less then 15 min. So I set the timer to flood the beds for 15 min every 90 min. Is that off time to long?. The beds are flooding and draining fine.But I worry about the roots drying and the plants dying. What do you think?. I started with about 10 Tilapia and when I was reading a Tilapia farming site it said you could cycle your system with as many fish as your tank would hold but you have to keep the PH below 8. Has anyone tried to cycling this way? Thanks for any help and pointers because i'm just getting into farming this way.

this thread covers it > viewtopic.php?f=4&t=21754
read down a bit for updated info and image size comments.
[ and there are various bits of information in the announcements area > viewforum.php?f=4 ]

re: timer.

don't panic about exact times etc, it doesn't make a lot of difference.
15mins on 45mins off is the normal one recomended.
I run my systems as 30-30 for example (30 mins on 30 mins off).
You really need the timer flows for the fish aeration - so if you only have the pump water for aeration then you may need a longer flow period anyway, or else you need additional air. The plants are happy whether they get refreshed water 4 times an hour or once an hour or even in cases once a day (provided good water is available/flowing in mean time)...

15-45/30-30 etc is only a guideline. So do whatever works for you around those sorts of levels.
If you think the fish will benefit run the pump a bit longer.
Just make sure as a minimum you turn at least one fish tank water volume over in a timer cycle.

plants grow fine in constant flood (CF) and DWC systems that don't drain at all.
but water circulation and aeration - Dissolved oxygen - is important.
siphons are basically filling for most of the time because they drain quickly - so their roots are always in water as well.

roots drying is dependent on the media and air temperature. clay balls for example will stay moist for hours.
you can check moisture by digging down and feeling how damp it is.

yes cycling with fish is quite common, as is fishless cycling.

the important rules are:
#1 don't have too many fish - else they will eat crap and die when the ammonia and/or nitrites build up.
you must stock well below normal stocking levels - else the fish will simply stress and maybe die.
i.e. just a few fish....
#2 you have to keep good aeration, circulation and dissolved oxygen, for some species should salt the fish tank.
this is particularly important during the nitrite phase.
#3 make sure the water temperatuers dont get to high. This is as bad as high pH for ammonia toxicity.

the graph that explains the pH and temp relationship to ammonia is here...
viewtopic.php?f=11&t=133 and here viewtopic.php?f=12&t=17374 (and various other places)

[ few other topics here > viewforum.php?f=11 ]