You have enough advice thrown at you already so as someone who is also very new I will just make some general statements and ramble for a bit (actually ended up really long winded).
Something I have discovered the hard way:
Assume any one person or especially fish store is a moron.
There are a ton of different ways to do everything in this hobby and what worked for one person might wipe out the tank of another person due to some small difference.
There is also a big problem with this hobby constantly evolving and what was the right way a few years ago might suddenly be the worst thing you could do this year. That also makes it so that some new methods and some old methods, both of which might work very well separately will totally clash and cause big problems if mixed together.
There are a lot of extremely knowledgeable people with very successful tanks on here that might give you what is essentially outdated advice simply because its the method they have always used and don't see any reason to change what works, even if for someone starting out there might be a better new way.
Also for every certainty there are people with exceptions. For example it is commonly known that you don't want to put two yellow watchman gobies in the same tank because they tend to not get along and will potentially fight if there isn't enough territory. Unfortunately that wasn't commonly known to the idiot at the fish store who sold my wife who didn't know any better two of them at the same time (from separate tanks at the store), along with 5 azure damsels which is another very questionable decision for a 75 gallon. Luckily there is just barely enough room and rocks for all the damsels to find a spot and be territorial at least until they get bigger or my wife adds more fish, and she got super lucky in that the gobies decided they like eachother and live in the same hole under some rock (no shrimp) and come out to feed together at food time.
That last thing I found is go incremental on when you add things and make sure its in the right order (especially different fish species) but go full bore on the quality of what you add the first time around. Unless you are giving up the hobby at some point you will eventually end up replacing all the starter crap so just get the good quality high end full featured stuff from the get go.
Specifically at the moment that would apply to the RO/DI system you keep asking about.
In my opinion you will eventually want an ro/di so just get the right one now.
www.bulkreefsupply.com
That is what I have, specifically the 75 gallon per day version. You get the higher output versions for a little bit more (only like $10 it looks like) if you want to make water faster. In my opinion this plus version of it that comes with the inline pressure gauge and TDS meter is a necessity to avoid problems slipping by you.
I don't know when someone would need more than the 4 stage as it just runs stuff through tighter carbon blocks twice it looks like with more stages. We have well water that makes a red sludge in the house water filter in only a few weeks and just the 4 stage gives me zero tds output. Its looking like the color change mixed di media will go before the other filters do.
Getting the right stuff for lighting and powerheads (not critical until coral get involved though it does effect algae) and whatnot is good to do right the first time. Controlability over power and timing on both of those things is pretty criticial and good stuff obviously costs more. Its very easy to buy cheap crap you will need to replace to get flow and lighting right on both of those. That is, its better to have too much and just turn it down than have not enough and have to replace.
I also had a heck of a time working out how to get the right flow to everywhere in the tank without blowing anything away. I still don't have that quite right. Normally I recommend people get the flow right before adding living stuff because it might require rearranging all sorts of stuff and moving the pumps 10 times which can be stressful to them.
But then it will also change after adding coral which will block water flow as they grow.
On that note figure out what coral you want ahead of time so you can get the lighting and flow almost right ahead of time and have compatible spots for everything you plan to get at least vaguely picked out.
I agree with the people that say don't panic, if the fish are happy the rest of the crap will get sorted out. I already nuked a new lawnmower blenny because of shoddy test equipment and mistakes letting the temp get up to 83 or 84 and a dkh of 6 the (acclimation was just too big a jump). So mess ups are to be expected.
Speaking of test equipment go with hanna digital testers for dkh and ulr phosphate if you want to save a ton of frustration with those worthless interpretive dancing chemical test ones, and make sure you have multiple good digital temp testers and a reliably reading old fashioned glass one hanging in the tank just to watch for major mechanical glitches.
Something I have discovered the hard way:
Assume any one person or especially fish store is a moron.
There are a ton of different ways to do everything in this hobby and what worked for one person might wipe out the tank of another person due to some small difference.
There is also a big problem with this hobby constantly evolving and what was the right way a few years ago might suddenly be the worst thing you could do this year. That also makes it so that some new methods and some old methods, both of which might work very well separately will totally clash and cause big problems if mixed together.
There are a lot of extremely knowledgeable people with very successful tanks on here that might give you what is essentially outdated advice simply because its the method they have always used and don't see any reason to change what works, even if for someone starting out there might be a better new way.
Also for every certainty there are people with exceptions. For example it is commonly known that you don't want to put two yellow watchman gobies in the same tank because they tend to not get along and will potentially fight if there isn't enough territory. Unfortunately that wasn't commonly known to the idiot at the fish store who sold my wife who didn't know any better two of them at the same time (from separate tanks at the store), along with 5 azure damsels which is another very questionable decision for a 75 gallon. Luckily there is just barely enough room and rocks for all the damsels to find a spot and be territorial at least until they get bigger or my wife adds more fish, and she got super lucky in that the gobies decided they like eachother and live in the same hole under some rock (no shrimp) and come out to feed together at food time.
That last thing I found is go incremental on when you add things and make sure its in the right order (especially different fish species) but go full bore on the quality of what you add the first time around. Unless you are giving up the hobby at some point you will eventually end up replacing all the starter crap so just get the good quality high end full featured stuff from the get go.
Specifically at the moment that would apply to the RO/DI system you keep asking about.
In my opinion you will eventually want an ro/di so just get the right one now.
4 Stage Value Plus RO/DI System
BRS 4 Stage Systems are perfect for reefers who have water treated with chlorine or relatively clean well water. Self-contained on a single bracket making them ideal for tight spaces or where a non-permanent connection may be required. Every BRS RODI system can be installed within minutes with...
www.bulkreefsupply.com
I don't know when someone would need more than the 4 stage as it just runs stuff through tighter carbon blocks twice it looks like with more stages. We have well water that makes a red sludge in the house water filter in only a few weeks and just the 4 stage gives me zero tds output. Its looking like the color change mixed di media will go before the other filters do.
Getting the right stuff for lighting and powerheads (not critical until coral get involved though it does effect algae) and whatnot is good to do right the first time. Controlability over power and timing on both of those things is pretty criticial and good stuff obviously costs more. Its very easy to buy cheap crap you will need to replace to get flow and lighting right on both of those. That is, its better to have too much and just turn it down than have not enough and have to replace.
I also had a heck of a time working out how to get the right flow to everywhere in the tank without blowing anything away. I still don't have that quite right. Normally I recommend people get the flow right before adding living stuff because it might require rearranging all sorts of stuff and moving the pumps 10 times which can be stressful to them.
But then it will also change after adding coral which will block water flow as they grow.
On that note figure out what coral you want ahead of time so you can get the lighting and flow almost right ahead of time and have compatible spots for everything you plan to get at least vaguely picked out.
I agree with the people that say don't panic, if the fish are happy the rest of the crap will get sorted out. I already nuked a new lawnmower blenny because of shoddy test equipment and mistakes letting the temp get up to 83 or 84 and a dkh of 6 the (acclimation was just too big a jump). So mess ups are to be expected.
Speaking of test equipment go with hanna digital testers for dkh and ulr phosphate if you want to save a ton of frustration with those worthless interpretive dancing chemical test ones, and make sure you have multiple good digital temp testers and a reliably reading old fashioned glass one hanging in the tank just to watch for major mechanical glitches.
