Hellooooooo
First off, LFS know as much about marine (or often less) than they do about freshwater as you've discovered they've totally contradicted each other through their lack of knowledge.
Both ways of cycling are equally valid and both will work. It comes down to personal choice. Here are some pros and cons for both.
No live rock:
Pros: No nasties (although bear in mind that any corals you get will need to be dipped or you may get them anyway)
You can get the pre-made rock in some nice shapes
Cons: You will have to cycle the tank using ammonia the same as you would a fresh so possible weeks of waiting. Even using the bacteria stuff.
You won't get any of the good guys that come with the live rock that do play a part in the marine ecosystem (you can buy things like copepods)
The pre-made rock (Aquaroche is one brand) is horribly expensive.
Live rock:
Pros: You have an almost instant cycle as the bacteria is already on the rock. A week of testing to make sure there isn't an ammonia spike if there's any bacteria die off due to it being moved.
You will get the good guys that arrive on the live rock. If you do get a pest hitchhiker you would deal with it the same way you would if there were snails or something in a fresh. Manual removal, a trap or treatment. Over time I bought over 20kg of the stuff and not once did I have anything unwanted. That's not to say you wont but it's not as common as it can be made out to be.
Maintenance:
In a small tank it's pretty much the same as fresh. Water change once a week. Glass scrape, gravel vac maybe. Unless you've got a heavily stocked tank with lots of corals that are using up all the elements in the water you won't need to be dosing every day. You would know the levels of elements in the water you make then during weekly testing you would be able to see how much of each is being used, calcium, magnesium etc. If the levels were dropping below the ideal range then you would top up. Over time you would get used to the amount which is how people set up auto dosing machines to put in the right amount. A bit like EI dosing for plant ferts. You need X amount each week divided by 6 or 7. Nothing to say you cant do it every few days or weekly. I didn't have a heavily stocked tank. It was mostly 'softies' and never needed to top up anything. I was able to keep the levels in the right range with decent water changes (20-25%).
Live sand: Don't bother. The bacteria will grow on the sand if using either method of cycling. It's a waste of money.
Filter: You can use one if you want. It will give extra flow too. Sponges and other media we use in fresh can be used. They have a reputation of being nitrate factories because they will produce nitrate if theyre not maintained properly. They need to be cleaned weekly. As with fresh, bacteria will grow in them but with sufficient rock and flow there will be enough bacteria to maintain the bioload. You could put live rock (seeded dry rock) in there I suppose for extra capacity (that's what I'd do) and maybe some filter floss to catch debris but that would need to be changed often, at least weekly.
Buying RO:
Fine to start with (long term you may want your own machine as the cost of it builds up). Quality can vary depending on the LFS. Always, always take a TDS pen with you and test their RO before buying, anything over 10ppm don't buy it. It shows they haven't changed their filters for a long time. You also want to test it for nitrate and phosphate which is another sign of bad husbandry at the store. Both should be zero. Never buy the pre-made saltwater either. Again the levels can vary a lot so best to mix your own. Get a good quality salt mix.
Live rock is expensive so you could get a little bit and the rest dry and it will get seeded but will take time to spread (think little bit of cycled media to get you going then stock slowly)
Evaporation. Get a lid
it's that simple. A piece of Perspex is not expensive. Even if you only put it on when you're away. If you had an open topped fresh tank at 25 degrees you'd need to top that up too.
The man in the shop saying you couldn't leave a salty for a few days is, to be perfectly honest, an idiot!!
Yes it's a learning curve but it's not as different to fresh as some like to make out. The basics are all the same there a just a few extra steps you need to add in.
There will be a cost of extra equipment you'll need to buy but not as much as people say (some salty people get very uppity about equipment). Here are the common things you'll hear/read.
"You have to have a sump"...…..No you don't
"You have to have a skimmer".....No you don't
"You have to dose daily"......No you don't
Good water, good salt, good light, good flow, good maintenance = good tank
Back to work now
but if I've missed anything let me know
Any more questions, feel free
Sorry for the essay
@"fr499y" can check me on details
hoping I haven't made any glaring errors!!
)
