How to Start a Saltwater Aquarium

A well-planned saltwater tank runs much better, is less cost because you aren’t replacing bad equipment, and gives you a much better start. There are a lot more possibilities, more questions to answer, and more equipment to decide on. A thorough understanding before you get started will help you save time, money, and hassle. A well-planned saltwater tank can run surprisingly well, a poorly planned system can be unbelievably frustrating.

Step 1 – Research

Saltwater, especially reefs, require a lot of research. If you just jump into a saltwater tank you are almost certainly going to create problems. No one has ever done too much research. No one has ever been too prepared for a reef tank. Saltwater systems are surprisingly different than freshwater, so there is a lot to get your head wrapped around, even if you have a lot of experience in freshwater tanks.

This may sound old-fashioned (and hypocritical, given this is a website), but books are still one of the best resources out there. There are a lot of great books out there, take advantage of this abundant information. Essential Saltwater Books

Websites are obviously another great resource. The benefits of websites are that the information can be more current and up-to-date and the authors can be more of an experienced hobbyist rather than a formal author. The biggest problem with websites though is that anyone can publish anything. This makes it very difficult for someone without experience to differentiate between logical sounding ideas and real, accurate experience.

Your research should include planning out your entire setup. Decide which sump design you are going to use, which return pump, which circulation pump in the display, which lights, how much rock and of what type, which sand, etc. Ask about it all. Post your plan on a couple popular forums and get feedback. Join a local aquarium club. Not only can you ask questions, but local clubs can be an excellent way to get great used equipment at a fraction of the cost of buying it all new.

Don’t just plan what you will need when you first get started, you should also plan on how you will add other equipment down the road. For example, your sump may be perfect for your protein skimmer, refugium, and return pump, but will you have room to add a media reactor and its pump? Do you have a spot designated for an automatic top off if you aren’t getting one right away? If you decide to upgrade your lights, will your setup limit your options? Having a plan for these makes adding them later MUCH easier.

I consider the minimum tank size for someone to start in saltwater to be 29 gallons, but a 40breeder is much better because of the 18″ width. The extra width makes it much easier to arrange your rock into a nice and stable formation that provides lots of space for corals. It also allows for a larger sump. Bigger is better, but don’t go bigger than you can afford to do properly. I have seen people buy large used tanks for cheap and then not be able to afford enough light, a large enough skimmer, enough rock, etc. In the end, the tank fails to thrive and they are constantly struggling with something. If they had kept to a smaller tank it would have looked phenomenal.

Although it doesn’t have to be set in stone, this is the best time to develop a clear idea of the livestock you want in the tank. Have a general idea of which fish you want, which corals you like, and an overall plan of what you want to have. It makes stocking much easier and helps make sure that the entire system will work well together. The last thing you want to do is rearrange all your live rock because you didn’t leave caves large enough for all the fish you will eventually be adding.

Step 2 – Get Everything Up and Running

Start buying your equipment. Go to your local fish store and order the tank (and stand too if you aren’t building it). Although saving money on good used equipment is good for most of your setup, the tank is a major exception. I personally will not use a used tank at all. The risks are too great. You have no idea how the tank was handled, how old it really is, etc. The potential damage that even a small leak can cause is more than even a large new tank.

If you are going to buy used equipment, start looking as early as possible. It can take some time to find the right deals. If you decide to go all new, or couldn’t find good deals on all the used equipment, talk to your local fish store about ordering everything you need. I know you can save a few dollars buying almost everything online, but you need your fish stores. As someone who now lives with NO fish stores within an hour and a half drive, trust me, you need your local fish stores. Support them as much as you can. If a price is a major issue, let them know and ask what they can do. Most would rather make a smaller profit (especially on a sure sale) than lose your business.

Once you have everything, start putting it together. Build your sump, drill your display, get it all ready to go. Once it’s ready, plumb it and hook it all up. Take your time and do it right. Paint the back, install internal overflow boxes over the bulkheads, try to find every little detail that will make it even better. Once it is ready, fill it up and get it running. You can add RO water and mix the salt in the tank the first time. Check for leaks, make sure the water level in the sump is where it should be and mark it accordingly. Get the protein skimmer positioned correctly. Even though there is no chaeto in the refugium yet, look at it very carefully and make sure it will be kept in the refugium section of the sump. Now is the time to find any problems and redo anything as necessary.

Build Your Own Custom Sump


Step 3 – Add Your Live Rock

The live rock is about 80% of your filtration, the home for the fish, and the structure of the reef. I consider the minimum to be 1 pound per gallon, but ideally you should have 2-3 pounds per gallon. The good news is that most of the rock can start as dry rock as long as the live rock that you do add is very good. Over time, the live rock will seed all the other rock and in about six months or so you won’t be able to tell the difference.

The live rock will need time to cure. The process of curing the live rock also cycles the system. There is no need to add ammonia, food, or anything else to cycle the tank.

Live Rock Guide

Step 4 – Start Stocking

This is the last and longest step. It is now time to start stocking. It is generally best to start with the most laid back fish so that they can settle in before more aggressive fish are added. It is also good to get some cleanup crew in right away so that they can stay ahead of the curve for the unavoidable algae blooms. As long as you have no reason to believe there are any issues with your chemistry (most importantly temperature, salinity, and pH) you can go ahead and start getting easy corals such as zoanthids and mushrooms. These are the least demanding, most forgiving, the perfect beginner corals, and most likely to live through any issues should they arise.

If you haven’t already as part of your research, definitely take your time to do so and stock very carefully. Reef safe sometimes isn’t reef safe.

Make sure you start doing water changes right away, 10% per week minimum. Don’t wait for problems to develop that prove you haven’t been doing enough water changes, do the water changes to prevent the problems.

Test very frequently at first and track it all. Whether you like to do things on paper or get excited at the thought of building your own spreadsheet, track it all. It makes it much easier to figure out issues and troubleshoot if you have all the data.