Grow beds fill/drain rate

[Wendell Ford]

I am in process of replacing my bio filters for my 10000 gallon Koi pond with grow beds. I have four large grow beds with bell siphons. It takes 30 min to fill and 15 min to drain. Would this rate be considered as good rate? If anyone has any words of wisdom concerning my grow beds before I plant sometime in March please feel free to chime in.


Thanks

Wendell

[Alex Veidel]

Wow, that's a lot of gallons. In an aquaponic system, you want to cycle through your systems water at least once an hour. Are you planning on replacing your filters completely with growbeds? Or just supplementing filtration?

[Wendell Ford]

My current bio filters are two IBC containers plumbed in series (550 gallon). I plan on the grow beds total volume of 685 gallons doing both duties if it works. Some of the volume of the grow beds will be taken up with medium. I have 25 Koi now and I feed them every day except winter (Jan Feb here) and I have never had any ammonia or Nitrates or Nitrites so the bio filters have been more than enough. I'm hoping the grow beds will still be sufficient filtration for my fish. This is all a learning process for me. My main concern now is the difference in the amount of time the beds are flooded and empty. Do the plants do better with more rapid flow or slower flow?
All help is appreciated.

[George]

Flood and drain rates are all over the map and yours seems OK to me.  Mine are about 10 mins flood and 20 drain.  That's a huge pond you have but a very light stocking.  All of the surfaces in your pond are also part of the biological filter so all total that's a lot of filtering.  It will interesting to see what happens as the fish population increases.  It all looks great.  

[Josiah Sherman]

Hi Wendell,

Like George I think your flood and drains rates are great. However I don't think you need to cycle through your water once an hour. I think that is a good idea if you have a high density of fish, but in your case I would recommend moving 10 to 20 gals of water per lb. of fish.

Hope that helps, Josiah

[George]

Hello Josiah - please post some recent photos.  You have the most unusual tank ever.  

[Vlad Jovanovic]

Yeah, Wendell your fill/drain times should be just fine...and I totally agree with Josiah in that there's really no point in you cycling through all that water once an hour with that fish stocking density. 

The plants and bacteria are fine as long as the media is not completely drying out between 'floodings'.

Now, flow rates can affect other things like solids and fines settling, O2 replenishing, stratification of the water column...blablabla and all those things certainly have their place (even if sometime that 'place' is just academic contention)...but really, with what you described, it doesn't seem like you'd need to worry about any of that. Just keep the media from drying out and you should be fine IMO.

[Josiah Sherman]

Hi George,

I'm uploading some more pics now :-) If you would like to see a lot more, I have pictures and videos here:

http://homesteadaquaponics.com/