dkeller_nc
New member
Hi ?April? - Welcome to Reef Central. You've gotten lots of advice/questions on this thread, and you're correct that the initial learning curve for reef tanks can be a bit steep, and it's quite possible to get a whole lot of potentially conflicting and confusing advice.
However, perhaps I can clarify this slightly. You'll notice that most of the posts are asking you about one of 3 things: water chemistry, flow, and light. And that is indeed the "big 3" when it comes to reef tanks.
Let's start with water chemistry.
Water chemistry concerns can be lumped into 4 categories: temp, salinity, nutrients and ionic composition.
Temperature (I realize temperature isn't water chemistry, but it's a convenient place to put it): Most reef creatures evolved in an incredibly consistent temperature range. In general, one wants to keep one's tank at 78 degF to 82 degF. The animals will tolerate a little lower and a little higher, but you're safe if you stay within this range. If you've an inexpensive digital aquarium thermometer, realize that you will want to check it against a more accurate alcohol or mercury thermometer.
Salinity - This is extremely important. Sea water on average has a specific gravity of 1.026 at 77 deg F, and that's what you want to emulate. While fish can tolerate a great deal of variation from natural levels, most invertebrates/corals cannot. The best way to measure and control this is with a digital refractometer.
The Milwaukee brand that Bulk Reef Supply and other sell is in very wide use in the reefing hobby, and is about as easy to use and accurate as you could hope for. Manual refractometers are cheaper, but can be a bit more difficult to use and calibrate.
A swing-arm hydrometer is at the bottom end of accuracy, but it can be made to work if you correctly calibrate it. Most swing-arms are way off from the factory, and it's important to know this and compensate for it. Also keep in mind that any salt or dirt buildup on the swing arm can drastically affect its accuracy.
An automatic top off unit is a good-to-have, but honestly you'd be better off spending your money on a good refractometer first. Simply draw a line on your sump with a sharpie when you've got your tank water correctly adjusted to 1.026, and add enough purified water twice daily to stay at that mark.
Nutrients: This you already have a pretty good grasp on. The two nutrients that folks concern themselves with after a tank has cycled are nitrates and phosphates. Since your tank has been setup for only a few months, you don't really need to worry too much about these just yet. As far as your ammonia readings, these are likely false. Any reef tank with a decent amount of live rock will have zero ammonia two or three months in unless a large animal has died unnoticed or a huge amount of food has been dumped into the tank.
Ionic Composition: There are 3 major ions that folks test for and adjust in a reef tank: Calcium, Carbonate (often referred to as alkalinity), and Magnesium. For your purposes, you really only need to worry about Calcium and Alkalinity for the moment. Most folks on this forum typically use the Salifert or the Red Sea Pro calcium and alkalinity tests, but the API kits for these ions will work, you just need consistency rather than absolute accuracy. To maintain your ion concentration at this point in your tank's life, you're probably best off simply doing 10% seawater changes per week. At some point in the near future, you can order some sodium bicarbonate and some calcium chloride and make your own solutions that you'll dose into your tank to maintain these ion concentrations.
A word about pH - stop testing for it. Saltwater is highly buffered, and will almost always be between 8.0 and 8.4 depending on the amount of carbon dioxide that's dissolved in it. Your animals aren't very sensitive to this parameter at all, and you definitely don't need to try to correct the pH in and of itself (i.e., don't add "pH buffers", ever, to your tank, even if the LFS recommends it - water changes with properly made saltwater are far better).
Flow: Flow is incredibly important in a reef tank both to prevent detritus from building up in the rockwork or other place in the tank, and also to agitate the surface of the water to promote good gas exchange. For this purpose, almost all reefers use propeller pumps nowadays. You can do this very cheaply with hydro Koralia pumps or other equivalent brands, or spend quite a lot on highly controllable pumps with sophisticated programming like the EcoTech Marine Vortech pumps. At this stage in your tank, I'd go with inexpensive always-on, constant-speed propeller pumps.
Finally, realize that you will either need to purchase highly purified water to use to make up evaporation and make new saltwater for water changes, or make it yourself. It's far cheaper and easier to make it yourself with an RODI unit, and Aquatic Life makes a small, compact unit called the RO Buddie that will work on your kitchen sink if space is at a premium.
In summary, your two most important "need to get" things at this point are an accurate way to measure specific gravity, and a good source for highly purified water. Your two most "need to do" things are keeping your salinity/specific gravity stable with regular RODI additions, and starting a routine of 10% seawater changes per week.
