Ah I see. Well first things first you will have to weed out all the fish that aren't reef-safe. ;)

Some test kits are in order. For calcium and alkalinity I would suggest API or Elos (or get your Salifert's calibrated against more accurate kits as they seem to be fairly unreliable). For magnesium I have found my Salifert to be trusty and easy to use.

If the coral load is low, once you dose the tank to the appropriate level, and pre-dose your water change water to appropriate levels you should be able to keep up to demand simply by doing weekly 10-25% water changes.

For supplements, I have always found that aquarium designed products produce better results (that often only experienced reefers may notice, so maybe not too important for more novice keepers). However, your tank is a significant size and it can get pricey to dose. As far as aquarium designed products go I have used many products and have found Fauna Marin Calcium chloride hydro-somethingorother to be my favourite calcium supplement on the market right now. I haven't tried their alkalinity supplement yet, but i am looking forward to it. :D For alkalinity I have been using SeaChem, and it works well. I prefer the Reef Buffer 8.3 to the Reef Builder product as the former mixes easier and helps keep pH over 8.0.

For magnesium I am using littlesilvermax's premixed ratio. I do like it, but I am going to try Fauna Marin's magnesium product when it runs out. I am so impressed with their calcium product I am going to switch all of my "big three" over to their products.

However, for just getting started I really see no reason to not use littlesilvermax's products for all of the "big three". Many seasoned reefers on here use his products exclusively. They are cheap, and they work.

good info guys.... thanks!!!

so.. the unit i bought was the Aqua fx 4 stage barracuda. it claims to be 50gpd but i filled a 5 gallon jug in less that an hour. is this common for a new unit or is something wrong?

ok... promise not to laugh?!?!

i had the drain line (waste water) in my bucket and the product line in the drain.. Whoops :redface:

its going a lot slower now...

couple of links (here and here) that show the roll off in output with cold water and reduced pressure below the ratings as well as something on rejection rates.

awesome! thanks Mark!!

there was mention of adding a piggyback membrane to improve your gpd. for future reference, do you know where i can pick one up?

also, if i were to change the membrane size to a 150gpd (i noticed from the links that were provided that some 150gpd membranes have a very good rejection rate) would i have to do anything special to the unit itself?

I have the exact same AquaFX Barracuda as you do. I bought a Flush Kit for my system too. I flush it for about 5 minutes after every use. It's a great little system. Mine is also 50 GPD. I found it great when I had a smaller tank, but for my 90 gallon I am looking at upgrading. After 2 years (or has it been 3?) my 50 GPD RO membrane is finally starting to get used up, so I will replace it with a 150 GPD membrane. Upgrading is simple, buy the 150 GPD membrane with the 98% rejection rate, and buy a 150 GPD flow restrictor. You will find the flow restrictor on the good water line. If you pull the line off it will be stuffed in the end of the tubing. So, just make sure the rating of the flow restrictor and the membrane match and you're good to go! :D

thanks myka!!

i am wondering if i should do the upgrade now. i have a 120 gallon tank.

where do you get your replacement cartridges?

In the past I have bought from Bulk Reef Supply, but I am going to order my next set from Kelly at The Reef Shoppe as his prices are very competitive.

thanks again myka!!

i will have to check them out...

you mentioned that the restrictor should go on the good water line but http://www.bulkreefsupply.com/store/...-your-membrane says to put it on the waste water line. are the barracudas set up differently?

and one last question... what do you store your water in? do you make up a bunch of ro water? i was thinking about buying a large plastic garbage can and storing the water in there.

The flow restrictor will be in the line that goes to your drain, the discarded water.