growbed depth and gravel pricing

[Bob Gee]

I am trying to find out what depths people have their beds set to and where I can get gravel in Florida that is reasonable in price. We have been looking at one foot deep and the prices for gravel are astronomical.

[Ron Thompson]

My bed is a foot deep.

 

I didn't locate acceptable gravel any cheaper than aliflor, which I found at Tropical Plant Products in Orlando at $22 for 2CF. For my next bed, I'm thinking f using Lava Rock to a depth of 6" then topping it with Aliflor. The lavarock can be had cheaper but is a bit to coarse (IMO) for the top of the plantings.

[TCLynx]

What do you see as astronomical?  Some people buy expanded clay or expanded shale for their grow beds and they are probably paying something over $800 for a cubic yard of the product once you figure in freight.  I've never been willing to pay that much for media seeing as I probably have around 18 tons here and the gravel usually costs between $50-100 plus delivery per ton or yard depending.

 

I started out with mostly 12 inch deep grow beds but have moved to mostly 24 inch deep beds now.

 

 

[Bob Gee]

Astronomical to me is $330 per ton for lava rock and $120 per ton for granite. It just seems to expensive to make this worth doing. I need 3 cubic yards to fill all six grow beds so my options are 1.5 tons of lava rock or 3 tons of granite or river rocks, which the river rocks are more expensive than granite at $180-$220 per ton. I am also having a hard time grasping why a shallower bed depth would cause a problem in the system.

[Conrad Chin-Yee]

TCLynx said:

What do you see as astronomical?  Some people buy expanded clay or expanded shale for their grow beds and they are probably paying something over $800 for a cubic yard of the product once you figure in freight.  I've never been willing to pay that much for media seeing as I probably have around 18 tons here and the gravel usually costs between $50-100 plus delivery per ton or yard depending.

I started out with mostly 12 inch deep grow beds but have moved to mostly 24 inch deep beds now.

TC,

are those 24" growbeds DWC/raft beds or beds full of gravel media? I am awaiting delivery of my moving-bed media for my recently completed filter setup and if it doesn't work well, I may be adding gravel media beds as that seem to be the cheapest around.

Kingjam

 

[TCLynx]

My 24" deep beds are gravel beds.  I'm lucky I guess cause the 1/2" brown river rock is nearly the cheapest gravel at pebble junction (aside from limestone pea gravel of course)

Here is a blog post with lots of pictures from spring 2010 when I started the....

 

I base my system designs on volume of filtration compared to volume of fish tank so for my big system with 700 gallons of fish tank, I like to have 1400 gallons of filtration.  If I were to space that all out in 12 inch deep beds it takes more space than if I have some beds that for the same footprint are twice the volume.  I still have some 12 inch deep beds but if I don't want to be bending over all the time, it costs a lot to build a stand to have a 12 inch deep bed up at waist high while the 100 gallon stock tanks I simply place them on 5 leveled concrete blocks and they are about the right height for me without having to spend $100 on building a stand.

 

Anyway, a shallower bed depth doesn't necessarily cause a problem as long as the system is still designed with enough filtration for the fish load.

 

There is always the option of going to a separate bio-filter raft type system but then you have the cost of styrofoam and net pots and extra aeration.

 

Good Luck finding a better rock supplier.

[Bob Gee]

Thank you for all of the help. I am so thankful for the help from every one. I didn't think about the system in terms of filtration. I am looking at filtering a 250 gallon fish tank with 500 gallons of grow bed. Is that two to one ratio something anyone has messed around with? How many fish do you have in a 700 gallon tank?

[Ron Thompson]

Where are you in Florida? 

 

Are those prices delivered? You might be able to save on delivery charge by checking craigslist for some guy with a dumptruck, they often will do a load for $50/$75

 

 

[TCLynx]

Yea, I like the numbers, 500 gallons of grow bed supporting 250 gallons of fish tank (expecting that you have a sump or some other means to handle the water level fluctuations if doing flood and drain.)  It is what I would call a 2:1 system and probably very similar to my backyard system where I now have 600 gallons of grow bed to a 300 gallon fish tank and an indexing valve sequencing through the grow beds so the fish tank never gets pumped down too low.

 

 

[Bob Gee]

I am in Naples and those prices would be pick up. Yea, I am looking there now and have com across some other stone suppliers.

Ron Thompson said:

Where are you in Florida? 

 

Are those prices delivered? You might be able to save on delivery charge by checking craigslist for some guy with a dumptruck, they often will do a load for $50/$75

 

 

[Bob Gee]

What is an indexing valve? I haven't heard of that.

TCLynx said:

Yea, I like the numbers, 500 gallons of grow bed supporting 250 gallons of fish tank (expecting that you have a sump or some other means to handle the water level fluctuations if doing flood and drain.)  It is what I would call a 2:1 system and probably very similar to my backyard system where I now have 600 gallons of grow bed to a 300 gallon fish tank and an indexing valve sequencing through the grow beds so the fish tank never gets pumped down too low.

 

 

[TCLynx]

Indexing Valves

 

or here is a link with some video of my 300 gallon system in the back yard back in Jan.

 

An indexing valve is a mechanical valve that each time the water stops then starts again it will move to a new outlet so you can say pump for 9 minutes then turn it off for a minute then pump for 9 minutes so the valve would sequence through 6 beds in an hour which is what I'm doing on my 300 gallon system.  Ya need a certain amount of pump strength to operate one of these valve but I've worked with the manufacturer on the gravity modified aquaponics indexing valve so I've been able to run my 300 gallon system with a 50 watt pump for the past year.

 

[Luis Arteaga]

Hi everyone, new in the forum and beginning to build a system, how much cost a indexing valve system and where can i get one? thanks for your help.