Cycling a SW Aquarium

Question
QUESTION: Hi,
I just set up a 29 gallon salt water FOWLR aquarium about a week ago. I have a protein skimmer and 2 koralia power heads. I used 28 lbs of Live Rock and about 2 inches of Live Sand.
PH is 8.2, temp is 80. When I bought the rock, about 3 hermit crabs and 2 snails came out when I got them home, so they are in there too!
Question: How do I know when this tank has cycled?
Some say I may never see a nitrIte or ammonia trace because of the sand and rock, but I am registering about 5 - 10 ppm nitrAte. Could this mean it is cycled?


ANSWER: Hey Joe,
I wouldnt think that would be the case in a weeks time, but it is possible. Depending on the quality of live sand you purchase(most brands come mostly dead) and the amount of die off from the live rock, a small system can cycle this fast. I would give it a few more days of testing, and add no more than 1 fish for the first 4 or 5 weeks, to make sure that the cycle has finished. This will prevent mini cycles and a constant battle with water quality. You should always see a small rise in levels in ALL new systems as they cycle though. They just tend to be smaller rather than huge spikes when the system has been set up well. Sounds like you have a really good start none the less. Just be patient, it truly pays off in marine aquaria. And let me know if you have any more questions.

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QUESTION: Thanks for the speedy reply!
I will be patient, but have one more question.
Is it really absolutely needed to have a refractometer rather than a hydrometer? I hate to spend the 75 bucks if the hydrometer gives a good enough reading using instant ocean.

ANSWER: Hey Joe,
You'll have many aquarists tell you Im daft and starting to thumb their noses at me, but NO. A refractometer IS better. However, there are many of us "old guys" that have used hydrometers for 30 years and more in our marine system/reef keeping. Effectively. So you can wait to afford a refractometer. As long as your patient and thorough when mixing sea water mix and aerate... the variance will be small.
And never clean your hydrometer with anything but clean tap water.

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QUESTION: Sorry Glenn - one more area to cover.
I was told 10% water changes weekly for SW, others told me no water changes. Which is correct?
Also, if water evaporates, salinity will rise, so what do you add back to the tank? Fresh water, or sea water to top it off?
Thanks, and that should cover it all

Answer
No worries Joe! Thats what I'm here for!
You'll find varying opinions regarding water changes(as with EVERY aspect of aquaria, lol!). It boils down to the type system you are changing the water for. A reef.... I wouldnt change more than 25 to 30% every 3 or 4 weeks. A FOWLR(fish only with live rock) system... No more than 50% every 3 to 4 weeks. If you have a strong biological filter(which YOU are going to), and good water movement you shouldnt have to do weekly water changes. As a matter of fact thats just unhealthy and stressful for a marine system. Most marine critters dont like big changes in water chemistry. I have all of my systems down to a 30% water change every 30 days. Now if you do happen to have water quality issues, frequent water changes and larger percentage water changes, are better for ANY system than poor environment and toxins.
Top off should be done with fresh water and ro/di water only! Unless you have great tap water, which most of us do not. Just treat your ro/di water with a conditioner mix and aerate a bit, and top off the tank. Be very careful to add only the amount that has evaporated. I guaranteed this by using a dry erase mark on a back/out of visibility corner of the tank for many years. Then I invested in auto-top off systems. They make some affordable, great units now that you may want to look into down the road. Especially if you live in a hotter region of the country. Let me know how it goes or if you need anything else!