Water top off?

I'm sort of new to the hobby, and this is the largest tank I've had. It's a 55 gallon. I tool my water into the LFS yesterday and the salinity was high. Nothing alive in the tank except a Halloween hermit crab. He used a refractometer, so it was accurate. I haven't seen any water evaporation (tank is completely covered) but there probably is some. More importantly, I have not seen any salt crust forming on the equipment. How much water should I put in and how often? Sould I top off with fresh water? Thanks for help in advance.

 

How much you top off has a ton of variables:

Tank temp
Ambient Room Temp
Ambient Room Humidity
Exposed surface area (is there an open sump with more surface area?)
etc.

You want your water level to stay the same all the time. Most people do not have their DT covered unless they have a sump that will allow gas exchange (expell CO2 and intake O2). For the moment you might be OK with just one hermit - but over time you are going to run into issues when you start stocking your tank.
If you go with open top - you are going to see more evaporation in all liklihood.

I have a 120DT with a 40BR sump and a 20Long refugium/protein skimmer remote tanke - all three are open and I go through about 1.5-2 gallons/day.

 

+1

Also you will use fresh water to top off. Salt will not evaporate with the water therefor raising salinity untill you return the water level in the tank to its original position.

 

Wow, thanks for the help. the tank is still cycling. It's had water in it for a little over a week. I do plan on getting a ReefCleaners CUC and Baserock later on.
I do have another question, its sort of off-topic for this thread. Does base rock create a new cycle to go through? Will it bring me back if I add it later? Thanks for your help.

 

If you plan on adding the rock later you will not create much of a cycle as there will be almost no die-off experienced to create a cycle. if you get baserock from Reefcleaners.org - I can personally attest to it's cleanliness and extreme porosity. A simple rinse with hot water followed by RODI water will do the trick. I used about 25lbs in my 30 gallon cube that was seeded with another 15 lbs of rock from another tank - I saw almost no cycle starting the tank.

It's best to add the rock before the CUC as there will not be much for the CUC to clean yet . . .

 

"Cycling" was a difficult concept for me to grasp. Dead base rock should have no life to die off. It is the dying process that causes spikes of toxic ammonia causing your tank life to die if it gets too high. But yet the cycling process triggers the growth of good bacteria to grow. You actually WANT a nice strong cycle to help jump start your systems bacterial colony. Many people toss in a dead uncooked shrimp for a week to jump start the bacterial colony. Your crab will think he is in hog heaven, AT FIRST. But as that shrimp decomposes the tank will get increasingly toxic and it is possible your crab would not survive this process. The alternative would be to wait 6 to 8 weeks, adding a small amount of "Live Rock" to seed the bacteria. You will pay more for live, live rock because it is already cycled and the dead or bad life, (i.e. flat worms, sponges, etc. have been removed by your LFS). It is a learning experience to start with an empty tank, aqua scape with your rock and aragonite substrata etc, toss in a dead shrimp and then test every day to watch your ammonia climb, your nitrites kick in, your nitrates climb, peak with a nice strong cycle upwards of 80-100 ppm of ammonia, then remove the decaying carcass, change 25% of the water with fresh salt water and watch your numbers begin to come back down. This process takes a couple weeks. Once your numbers are all stable and low. (approx 4 weeks) then you may add a cheap fish, usually a damsel for 5 bucks. After one week you may add another fish or a crab. You really should not shortcut this process as you run a huge risk of a "crash" where everything dies because you do not have the bacterial colony to support the life you have added. I found by testing and watching my chemistry numbers change it helped me to understand water chemistry, and deal with problems down the road. My apologies if you already knew all this.

 

Thanks for the help. the next thing thats going in my card is 50 lbs of RC Caribbean BR. I've also been hearing of people putting shrimp in their tanks during cycling. It sounds like it speeds up the bacterial cycle, but wouldn't it make nitrates? And would frozen mysis work?

 

for topping off you can put like a sticker where you want the tank water to be at, and if it goes lower top off with ro/di water

 

What did you use to start the cycle? Do you have any rock or sand in there, or just a hermit?

 

I've got about 11 lbs of live rock, and 40 lbs of Aragonite sand.