Backyard Aquaponics
A place to discuss aquaponics

I am wondering what diameter standpipe I would need to allow 5000 gallons per hour flow down through it? I do not want overflow

According to http://www.pipeflowcalculations.com/flowrate/index.htm

a 0.7 in diameter pipe could do 5000 gal/h

pressurized?

I mean my pipe will have only gravity as pressure... Cause the pipe on my pump is 1.5 inch ID

The calculator uses the input velocity, which can be used to simulate a non-pressurized situation.

An easier way to go with a timer flood and drain is to use the same size pipe as your inlet, and you can vary the inlet holes to the standpipe to control your flow rate.

I found that my limiting factor was the flow rate through the gravel more than the size of the drain pipe.

What is the situation that you are going to ask a single growbed drain to handle 5000 gallons an hour?

I would probably go with a drain at least one size up from your inlet pipe. If using lots of pressure on the inlet, then perhaps a drain pipe twice the size of the inlet.

Hmm I just thought of something I will have to get back about how its a problem Draw up a diagram or something

5000 gal/hr =~84 gal/min.

I don't think you will get that out of a 1 hp pump after two filters.

Four inch should handle more than enough flow based upon the above figures.
But I would use six inch personally. Because.....

I always tend to oversize my standpipes when possible for various reasons. One reason is if it gets clogged by a fish or possibly a plant. Another reason being, if you want to rapidly drain the tank for cleaning, fish harvest, gravel washing or something else. Do you want to wait thirty minutes or longer to drain the tank down and do your job? I don't.

Standpipes don't use too much material, go ahead and oversize it.

Another thing to consider is rainfall, unless indoors. Or in NM

hope that helps.

Yeah I think the filters will slow it down a slight bit however I am not going to be pushing a huge amount of head pressure as the pump was designed. I think most of these are designed for 10+ foot without batting a eye running a pool. I will have about 30 inches of head pressure needed.

I was thinking 6 inch standpipe as well and its not like it will be all too expensive as it will break into multiple pipes rather swiftly to drain to the other beds.

About rainfall in NM It can get hardcore in the bursts as the link below provides how people sadly do not heed warnings and get killed by water here
http://www.amafca.org/ '

And thank you very much for the input Now I just need to come up with how to drain the solids in a way that I will draw up on paper to explain.

Alright here is a quick image I drew up I do not know if this is going to work fully or not but I figure it might work given the water flow... However I want to make sure that the solids are pulled out of the tank and thinking of how to do this is difficult given the way everything would work.

Which way is up in your diagram? With the pump the way it is, it looks like your fish tank is above your growbeds.

This can be done, but it's unusual unless you are spread out on a hillside

I was thinking the same thing....

Everything is going to be done on level ground this is the problem.. I cannot bury anything so yeah.. figure that being all laying flat on the ground. If you have better ideas I am all ears.

Help me understand then.... Will the tops of the grow beds actually be lower than the top of your water tank? If so, I am wondering if it would not be a better idea to raise the grow beds up so the bottoms are just over the level of the tank. I know this may get your grow beds up high but If I am understanding, the way you have it, the grow beds would not have the benefit of the solids being pumped out of the tank. I had to do the same thing because my tank is above ground, cement and on a rental property. A step ladder is my best friend for maintaining the grow beds but is that an option?

Not really a option to be cost effective :/ I think the neighbors would complain too LOL

If the tank is above ground and the grow beds sit on the ground, you can easily do this. Look up venturi drain. it is a way to pull water/solids off the bottom of the tank while not risking siphoning the tank dry.
This could work kinda like a CLIFT PIST system but you would need to have a sump to provide the extra water needed to make it work.