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New saltwater tank

27K views 288 replies 11 participants last post by  terryap 
#1 ·
Hi everyone

I recently started a 20 gallon saltwater tank, I need some help with knowing where I am for the cycle...
tank has been running about a week with cured live rock.
I tested the water and both ammonia and nitrite are at 0, nitrate was at 5.
would appreciate some help with knowing where about I am.

I plan on getting 2 -3 small fish max, would also appreciate any suggestions

Thanks
 
#3 ·
If the live rock you purchased was cured, then your aquarium is already cycled. That being said, lets talk marine tanks for a minute.

A cycled aquarium, being one that has the bacteria in place to process ammonia and nitrite, is not something to be overly excited about. More important than being cycled, is the general concept of having a "mature" aquarium. When we speak of a mature aquarium, we are talking about a few things.

First, the water has cycled. Second, the diatom bloom will have come and passed. The diatom bloom is a brown algae that quickly spreads across your sand bed and rock, and then receeds to a minimal problem. Third, you will notice that populations of copepods and amphipods begin to spread and are visible on your glass in great numbers. Finally, you will see coraline algae begin to cover your live rock and possibly the glass.

These signs of maturity are how you should judge the stability of your aquarium and its ability to support life.

I will check in again with you tonight to see if you have follow up questions about any of these concepts.
 
#4 ·
Thanks for all the info, there are a few living organisms on the rocks, not quite sure what they are, they are white tubes with a wider round part at the end, and they only come out when I open the light, and plenty of purple (different shades), light reddish and pinkish white and very little dark green coverage on the live rock already, hope this is an indication that the tank is somwhat ready for inverts?
 
#6 ·
What you are seeing is the normal progression of live rock as it settles into the tank. The majority of what you see now will slowly disappear and be replaced by coraline algae growth, which is what you want and is a sign of a stable environment.

Your nitrates are rising because some life on the rock is dying off, which is typical after a transition to a new tank. Your pH of 8.4 does not tell us much, because you need to test for alkalinity and calcium in order to correctly interpret the pH reading. Actually, going forward, the most important test for you will be alkalinity, calcium, and nitrate. These test need to be done weekly, and adjustments made when necessary to maintain the desired range.

On the subject of nitrate, we need to discuss your filter system and sand depth. Can you give some details?
 
#7 ·
thanks, sand is aragonite #4 nature's ocean, about 3 inches, skimmer is seaclone 100 ( I know, I have read the reviews..., I plan on getting a much more efficient model in a few months)
and have 30 lbs of live rock in the 20 gallon.
plus 2 power heads.

hope the above gives you enough info, appreciate your info

thanks
 
#10 ·
I think your Seaclone is an excellent skimmer for your size tank. I would not think about an upgrade.

You do have an issue with the depth of your sand bed. At depths between 1'' and 4'', denitrification is limited and detritus tends to accumulate, resulting in increasing phosphate levels and algae outbreaks. You want to target less than 1'' of sand, or even better between 4'' and 6'' for effective denitrification.
 
#11 · (Edited)
Skimmer has not been skimming anything yet though, but I've read since there is nothing in the tank except live rock, there is really nothing to skim.....and that it may require a break in time.
I will remove some of the sand to make around an inch, ( as I've already spent alot of $$$).
and one day, I will be upgrading to a larger tank, but for now I'll start with this and test my skill.

so any suggestions for good starter fish (small) or inverts? or mushrooms that do not require special lighting?
Also, which order should these be bought in? inverts, mushrooms and then fish last??

Thanks !!!!
 
#12 ·
For a test of skill, a 20 gallon tank is a challenge! Many newcomers to the saltwater hobby have the idea that they will do a small tank to "see how it goes." In the real world, aquariums smaller than 75 gallons are much more difficult to maintain and often drive people out of the hobby. So, if this does not turn out how you expect, the best thing to do is buy a bigger tank!

As for the order of adding your livestock, it really isn't relevant. You will only have 2 or at the most 3 very small fish in a 20 gallon reef. The order in which you add the fish is going to be the biggest decision and probably the only decision that could really cause problems, in terms of what to add when.

Any idea on what fish you want?
 
#15 ·
For a Clownfish in a 20 gallon tank, you will want an Ocellaris. The Tomato will become much more aggressive. Look for a tank raised Ocellaris. It will cost you are few dollars more, but the fish will be much more hardy and easy to care for. Plus, you won't be taking a fish from the ocean.

A Purple Firefish is an option, but these fish are usually kept in pairs and often become stressed when kept alone.

"Goby" is a rather broad term. If you are referring to a Mandarine Goby, beware that these fish are extremely difficult to keep and almost impossible to keep in aquariums under 75 gallons. They have such a huge demand for copepods and amphipods in their diet that aquariums under 75 gallons simply do not have a large enough population for the fish to eat well. On the flip side, a Watchman. Wheelers, Candycane, or Diamond Goby would be a great option.

Another great choice for you would be a Royal Gramma. These are interesting little fish and generally easy to keep.
 
#16 ·
I was also thinking about the royal gramma, I was not thinking about the mandarin, I have read how difficult they are to keep, I was think of more the citrus clown goby, and yes definately tank bred, I have been doing some reading and have read they are much hardier and disease resistant, but I did not know the firefish are usually kept in pairs, I will cross this off my list, I also like the Cardinal fish, the black and white one looks interseting as well, but my favorite is the wartskin angler, I love this fish!!!! But I know I can't get it :(
maybe in a few years, thanks again for all your knowledge you have been a great help.
another question, are crabs and peppermint shrimp compatible ?
 
#18 ·
Not for a 20 gallon thank. These fish are every bit as difficult as the Mandarine Goby, for the exact same reasons. Instead, look at the Sailfin Blenny (aka Jeweled Rock Skipper) as an alternative. The colors are similar and it is a much easier fish to keep.
 
#23 ·
Another question...can crushed coral and live sand be mixed together for a substrate?
I've also added a fish a couple of days ago, I know you mentioned the tomato clown can become aggresive as it matures, but I had to have it, I love them, it is about 1'1/2, I also added 5 red legged hermit crabs, tests are all clear, and fish seems to be healthy, was shy for the first 2 days.....not anymore, I am thinking of making it the only fish in the aquarium and maybe adding a couple of mushrooms, and a blood shrimp, would this be ok for the 20 gallon? I don't want to overload the tank......

thanks
 
#24 · (Edited)
I think it would be perfect to leave the Tomato Clown as the only fish. Not only is it territorial, but they grow larger than the Ocellaris and require more space.

As for mixing crushed coral with live sand, not a problem at face value. First, lets review this situation. How do you plan to go about mixing crushed coral into an existing aquarium? There will be a tremendous amount of cloudiness, and possible die off of existing bacteria in the live sand. Your best option is to add more live sand, given that the aquarium is already running.
 
#27 ·
You can add the live sand on top, and you should do so. Most live sand is rather clean and will not cloud the water nearly as much. Go for it!

I would do a small amount at first to see how cloudy the tank gets. Then slowly spread it out.

By the way, I would err on the side of caution and use 5'' total depth. You are pushing your luck just slightly by having a larger grain size crushed coral bed beneath the live sand. The extra inch of sand is added "insurance" so to speak. 6'' would be even better.
 
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