Sizing Grow beds

[Wayne]

I'm a little confused about how to size the beds for my system. I have seen a 1/1 ratio recommended for backyard AP, But also they recommend circulating all the fish tanks water every hour. I know it will depend on stocking density so lets say around 160-180 fish. I wanted to raise Tilapia but am considering catfish instead.

 

I have a 1200 gallon fish tank.

I guess my question is do you count the total volume of the bed or just how much water it actually takes to fill it? I have river rock for medium so for a 60gl GB it takes around 20gls to fill. 

 

What I had originally planned for was to have ten 60gl beds that flood and drain twice an hour. If you only count the 20 gallons it takes to fill them each time that would call for 30 GBs. 

Am I way off base or over complicating things as usual?

 

 

 

[TCLynx]

Yea, upsizing the pump is generally a good idea.

 

for my systems with a 300 gallon fish tank I have been using the Quiet One 4000 pumps which I believe are like a 900 or so GPH pump so once I pump up some height I might be pumping 600 gallons per hour if I'm lucky and I like that for my 300 gallon systems.

 

For my system with a 700 gallon fish tank, I'm using a much bigger pump and I think an 1800 gph pump would be a bit small to run that whole system so I would definitely upsize from there.

[Lonny Harper]

TC - I read a little more, and he admits his numbers don't work on a CHOP system.  my grow beds will be 12 inches deep.  I'm going to go with a 500-600 gallon fish tank with a 450 gallon sump.  I will increase my fish density to 30 lbs per 250 gallons at full grown (this number is based on Dr. Lennard's program).

 

David, I will definitely take your advice.  The extra flow will help with aeration.  I might even add more grow beds down the road???

 

That brings up two more questions that don't fit in this conversation, but I'll ask anyway.  1) I'm still trying to figure out how to build my fish tank and sump tank.  I know how to do the math for dimensions, but I need help figuring out materials.  Any suggestions.  The fish tank will be above ground while the sump will be mostly below.  Is there an easier way than blocks and cement? 2) Question one leads into this.  two IBC containers would give me approximately 550 gallons.  Is it possible to have these tanks hooked up to each other growing Tilapia in one tank and Catfish in the other?  Or do I need one tank with one type of fish?

 

If this has been discussed, I don't mean to re-hash it.  I have looked around and haven't found very specific answers.

 

Thanks

[TCLynx]

Well Lonny, there are many many ways of doing things, there is no single "right way" there is only a best way for your particular situation and a huge part of figuring out what is best will be your preference and how well it works out for you.

 

IBC tanks can work and you can connect them together but you might do even better to flow water through each of them separately, as in have water flowing into each of them from the pump and have each tank with it's own SLO drain feeding to the grow beds, this way you might be able to keep things isolated a bit better and avoid issues with the connector between the two tanks clogging.  Personally I think and IBC is just barely big enough to grow out catfish but that may be my bias and tendency to grow monsters, I like to have a full 300 gallons of water in the tank for channel catfish grow out.

 

As for sinking tanks in the ground, how you go about dealing with sump tanks will depend on your climate and water table.  Concrete is probably a good idea for an in ground sump if you are in a place that can get heavy rains that could float a plastic sump tank and pop it out of the ground busting up your plumbing!  If heavy rains are not likely then you could sink other tanks down in the ground.  Here in FL any tank I have sunk in the ground should be kept full of water at least up to the soil line and the top rim needs to be about 8 inches above grade to avoid having water flood over into the tank along with dirt/debris.

 

Above ground tanks.  all sorts of things will work.  Plastic round tanks of appropriate size or IBC's but you need to protect them from the sun or they will get brittle with age and algae may tend to grow in them too.  Or I've even used cattle panels and pond liner to make round tanks.

 

You can do multiple types of fish in a system as long as their living conditions are compatible.  Keep in mind that catfish can't take quiet the same abuse of horrible water quality that tilapia can and they will do much better if you don't put them in a system till after it is fully cycled up and you can keep the water quality high for them.  Also, you can treat tilapia with rather high salt levels if certain diseases present but catfish are definitely fresh water fish and you can't take salt levels very high for them at all (I only got to about 3 ppt of salt when treating issues in catfish or bluegill.)  Catfish can take cold though that would kill tilapia and catfish will even keep eating in cool water when the tilapia have basically gone into hibernation.

 

More grow beds later, more grow beds area always a good idea, if you can make the sump tank big enough to handle adding more you will save yourself issues later.