Reddit reviews Ade Advanced Optics Dual Scale 1.0 to 1.070 S.G. Salinity Refractometer for Aquarium & Seawater

Drops in salinity are way less harmful than increases - lower levels of salt mean higher oxygen content in the water so going that direction is not a problem. Increases in salt make it harder for your fish to breathe. Get yourself one of these too, makes measuring salinity way more accurate: Salinity Refractometer, Aquarium & Seawater - Dual Scale (1.0 to 1.070 S.G.) by Agriculture Solutions https://www.amazon.com/dp/B005ES6MOQ/ref=cm_sw_r_cp_api_Km.yybRYQ0EZS

I highly recommend a refractometer instead of the cheaper salinity checkers that you fill with water and look at where the arm floats to. Before I switched to a refractometer, my salinity was way off because of microbubbles on the arm that made it read higher than it really was.

Came to say exactly this.. There's one on there right now that's right at 25$ that i'd been looking at this week:

https://www.amazon.com/Ade-Advanced-Optics-Salinity-Refractometer/dp/B005ES6MOQ/ref=sr_1_10?ie=UTF8&qid=1522523470&sr=8-10&keywords=refractometer

• The D120 is the way to go for lighting. You'll probably run it at 30-50% depending on what corals you put in.
  
  
• The 200g box of Reef Crystals is certainly the most economic way to prepare water. It's about a year and a half's supply for a 10g in four separate bags. If you're making your own water, you'll want a RODI filter too, BRS or Spectrapure sells the 4 stage which is plenty. I should note--for a 10g, it's probably cheaper to just buy prepared water from a LFS.
  
  
• A refractometer costs only a little bit more than a hydrometer but is significantly more reliable since it can compensate for temperature.
  
  
• You can typically save money if you buy your live/dry rock at a LFS instead of online--mixing the two will save you more money! You'll also get to pick the pieces.
  
  
• Buy this heater.

This is a copy/paste from another thread I did on this tank:

Hey!
So I was in your boat 3 months ago and with the help of some local saltwater guys I got my tank up and running. https://www.youtube.com/watch?v=nT9FtqEUfgE[1] (looks a lot different now since i did some rescaping... I'll put a new video up soon)
Anywhosel... Don't go cheap... With anything... If you have to buy one piece at a time until you've got all your pieces do that. What I have:

Tank: http://www.amazon.com/Fluval-Spec-Aquarium-5-Gallon-Black/dp/B0089E5VLC/ref=sr_1_1?ie=UTF8&qid=1392354430&sr=8-1&keywords=fluval+spec+5[2]

Lights: http://www.amazon.com/Current-USA-Marine-Aquarium-24-Inch/dp/B00GFTK7CQ/ref=sr_1_4?ie=UTF8&qid=1392354461&sr=8-4&keywords=orbit+usa+lights[3]

Pump: http://www.amazon.com/Marineland-Mini-Jet-Powerhead-VERSION-Misc/dp/B009LN1HWW/ref=sr_1_1?s=pet-supplies&ie=UTF8&qid=1392354739&sr=1-1&keywords=mini+jet+606[4]

Powerhead: http://www.amazon.com/EcoTech-Marine-VorTech-Propeller-Aquarium/dp/B003HLO636/ref=sr_1_1?ie=UTF8&qid=1392354535&sr=8-1&keywords=vortech+mp10[5]

Gravity Tester: http://www.amazon.com/Salinity-Refractometer-Aquarium-Seawater-Agriculture/dp/B005ES6MOQ/ref=sr_1_1?s=pet-supplies&ie=UTF8&qid=1392354641&sr=1-1&keywords=Refractometer[6]

Glass Cleaner: http://www.amazon.com/dp/B0061PIRGW/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=20GUT5T0T21NZ&coliid=I1FAC5MICMTB5T[7]

I had freshwater fish before the saltwater and it's wayyy more maintenance but way more fun. You will want to abandon the freshwater the moment you get the saltwater up and running.