newbie questions

[Andrew]

hey all i am new to this forum and new to aquaponics.  I have several questions about a new set up,  ill start with just a couple.  I heard this is the right place to be for help :-).

I am going to be setting up just a small system first as a learning experience.  I will be using two 20 gallon totes.  I decided i am going to be using a flood and drain system.  I successfully made a bell siphon and ran the system with just water.  So as of now i have a tote on top and a tote on bottom.  the bottom tote pumps to the top tote once it gets full it drains out. 

My first question is does it matter what I use for media.  i know that hydroton is used by most.  however i have several bags of fish tank gravel.  can this be used without a problem.  also i have several bigger rocks from an old saltwater system i had,  used to be "live rock"  but its been cleaned and been sitting for a couple years now.  can i use this.  the rock is nice and pourous and i think would be good for the roots to grow threw.

my next question is should i use a bio filter.  i know seeing its flood and drain that technically acts as a filter but i have seen people recommend the use of a bio filter anyways. what do yall think.

[Jonathan Kadish NYC AA Chair]

Your FT gravel should be fine, just do a fizz test with vinegar and make sure it doesn't fizz a lot. If it does fizz a lot it will cause your ph to be too high. If your volumes are equal, fish tank to GB you should be fine for filtration.

[TCLynx]

Fish tank gravel may be on the small side for use in a media bed and the live rock may or may not cause elevated pH.  You don't have to get hydroton though, you can use river gravel.  To fill a 20 gallon tote you will probably need about 3 cubic feet of gravel (or six 1/2 cubic foot bags if getting it from Lowes or something like that.)  I too recommend doing the fizz test on a sample of the rock first before buying a bunch of it since limestone or marble will cause elevated pH and the plants will struggle.

Just be ware that a 20 gallon system will tend to experience extreme temperature swings if outdoors since it is such a small volume of water so give some thought to protecting it from extreme sun or cold and choose a fish that can handle extreme swings (the better goldfish seem to be a good choice from what I've seen though mosquito fish I hear are really good for extremes too.)