Hi there Meseria and welcome
What part of Florida are you in? I'm in Central FL (Just a bit NW of Orlando.)
Here is the link to my Big System Thread
http://backyardaquaponics.com/forum/viewtopic.php?f=18&t=2640
Just an FYI 70 F water temp might keep tilapia alive just fine but they don't grow fast at that temperature. They are really more like Tropical fish in that they grow and breed better in the mid 80 F range. Also, trying to grow indoors will definitely use much more electricity for lighting, probably require heating of the fish tank (if you want tilapia to grow fast) and you will also probably need to add extra dehumidification to the house to avoid mold problems. Florida really is a great place for outdoor gardening year round if you choose fish that will be ok with cooler water in winter but still survive the very warm water in summer. Tilapia are ok for outdoor systems in central and south FL if you can provide some supplemental heat through the freeze warnings and cold weeks. Channel Catfish can survive it and even keep eating without the supplemental heat.
That aside. A test system is a good idea. Avoid unlined galvanized tanks. Avoid limestone gravel. Look for 1/2" Brown River Rock. Pebble Junction in Sanford has a pretty good price on it. You can get some washed shells there for buffering or just get a bag of shell grit like used for laying chickens.
Here is a link for the test kit that most of us use.
http://www.thatpetplace.com/pet/prod/199591/product.web
Another handy place to look for some specialized parts,
http://www.aquaticeco.com/index.php
And here is where I've been getting my pond liner
http://www.justliners.com/aboutus.htm
Just about anything can be grown in Hydorponics or Aquaponics though some things will be easier than others and different methods are more appropriate to different things. Stuff that likes it really acidic might be tricky in AP since one usually wants to keep the pH up a bit to keep the bio-filter going well and if you have well water from a limestone aquifer, it will up your pH a bit whenever you top up. However, I am certain some people have managed it well. Root crops just need to be able to push media out of their way as they grow so light weight media might be better for them or having grow beds of a shape that allow media to be pushed up easily would help. Flowering crops sometimes need extra potassium if the fish feed doesn't provide enough. If your water supply doesn't have enough Iron, some supplemental iron may be needed.
Maxicrop is a good source of potassium and micro nutrients. If you can't find chleated iron, liquid iron might do in a pinch. I got a bag of green sand that I am now trying to see if it works to supplement both potassium and iron. I have also used a few hand fulls of worm castings through the grow beds to help get a good bacteria colony going in a brand new system. Actually a few hand fulls of composting worms right in the grow beds are a really good thing to help break down the solid fish wastes as well as old roots and other things in the beds. Composting worms are quite happy in flood and drain gravel beds.
Anyway, good luck and do lots of reading and ask lots of questions. There are actually several of us in Florida now. I've currently got Channel Catfish and Blue Tilapia in an outdoor system (that I can cover in plastic for the winter.) Jazzyplayermark is also in central FL and growing Tilapia, his fish are inside a shed while his grow beds are out in a greenhouse. JohnnyH is a bit further North and working hard on his AP system. There are several other Florida members that have not been as active lately but are still out there.
Welcome
