Hi Anthony, I saw your thread on the AI Prime in "Lighting and other Equipment" section, and your question from the 2nd of March on lighting another tank that didn't get any replies.
I've been doing this for about 25 years, and I very much like nanos - my current 20 gallon nano has been running since 2004. So maybe I can help a budding hobbyist along that has similar interests.
Keep in mind that I don't know what you know. So if what's below is "yeah dude, I already know that", my apologies in advance.
Let's address your current tank first. You've clearly got the basics down from the standpoint of cycling since your tank's now 3 months old, and you've done relatively well with your first animals.
So - let's talk about your maintenance routine that will help your first coral acquisitions do well. Maintaining good water chemistry is essential to success with corals, much more so than with fish, so here's the basics:
Water temp - can have a "setpoint" from 76 to 84 degrees, with the most common range that most reefers use varying between 78 and 80 degrees F. Regardless, stability is important. You don't want your nano heating up because of being sited near a window that will get spring sun.
Specific Gravity - you've clearly already gotten a measuring device, or you're buying your saltwater from an LFS. Typically, folks use refractometers because of the small sample size. We used to use hygrometers in the 1980s and 90s, and those work extremely well to
if they're calibrated; they're not accurate right out of the box, nor are refractometers. If you've a refractometer, get a 1.026 refractometry calibration solution from a place like Bulk Reef Supply. If you've a hydrometer, the best course is to go to a LFS and ask to let you test their water, and compare the readings. In any event, you want to maintain 1.026, with make-up water added
daily. Stability, again, is more important than the set-point within a fairly narrow range.
Nutrients: Ideally, you need a nitrate test kit. Phosphate can wait. Shoot for nitrates <10 ppm, but not zero.
Calcium and Alkalinity: Because you've added stony corals, you need to get a Calcium and Alkalinity test kit, and test your tank water every three days or so until you're confident of stability. Shoot for 450 ppm Calcium, and 8 dKH for alkalinity. The calcium can vary quite a bit - from 380 ppm to 500 ppm and not cause any issues. Alkalinity should be kept within about 7.5 - 8.5 dKH. You can also shoot for a slightly higher "setpoint" for alkalinity of 9 dKH, in which case the range should be 8.5 - 9.5 dKH. Alkalinity stability is the single most important water chemistry parameter after specific gravity.
To maintain the calcium and alkalinity, you are likely to have to do "2-part dosing", as water changes alone are unlikely to be enough.
Here's a good article explaining the relationship between calcium and alkalinity, and
here's an article about preparing the 2-part solutions yourself - it's far cheaper than using commercial 2-part products, and you can get the sodium bicarbonate from the grocery store and the calcium chloride from any number of mail-order reef suppliers (as well as food suppliers).
Water Changes: Because you've a small tank, and it doesn't look like you've a skimmer, you'll need to change more of the water more often than a bigger tank with a skimmer. That's OK, many nano folks change nearly 100% of the water in their tank every week or two, though I don't recommend that you do that yet. In order to make that water change schedule work, you need to use a high-quality salt mix that's consistent, and you have to be very cognizant of the new saltwater's specific gravity, temperature, and especially, alkalinity. Instead, I'd recommend that you change 2.5 gallons every week, and up to 5 gallons if you have trouble controlling nitrates.
With respect to your light choice for an upcoming 20 gallon tank, I'd
strongly recommend you go retro and get 4 24" T5HO bulbs over the tank. Two Aquatic life Marquis units would set you back about $225 USD with bulbs, and they include timers built in to the units. It's not as cool as an LED fixture, but you won't have to think about spectrum or intensity, there's no risk of burning your corals, and they're bullet-proof - they will grow anything you want, from SPS corals to tridacna clams to acans. The nano that I mentioned earlier has been using 460nm & actinic white PC bulbs since 2004, and I harvest acropora and montipora out of it every 4 weeks because the colonies overgrow the tank. LED will work, but it's much trickier. If you go this route, I'd recommend 2 Kessil A160we lights (for a 2 foot, 20g high nano), though you will need to buy the spectral controller with them to get built-in timers (though you can also use simple wall timers with these).
When you go to your new nano, consider the idea of drilling it yourself and installing an overflow, such as sold by
CPR. Use a standard 10 gallon tank as a sump, no baffles required. Doing this will allow you to include an ATO, skimmer, and a reactor for carbon and/or GFO in the future, and having a sump will give you a
lot more choices as far as a skimmer is concerned.
