9 Saltwater Tank Habits to Stop Doing Right Now

When managing a saltwater tank, it is useful to know what not to do.


If you know what to ignore, you’ll avoid mistakes and save yourself headaches.

Here are the top 9 saltwater tank habits to avoid:

#1: Do not feed your corals.

To avoid having a tank overrun with algae, do not pump a lot of nutrients (coral food) into your tank. Fish poop is great coral food so instead feed your fish well. 2 to 3 times a day is good for them, and for your coral.

#2: Do not use tap water or bottled water for your tank.

Both are full of metals and minerals you don’t want in your tank. Both can cause fish and coral to die and spur nuisance algae growth. Instead, use only RO/DI water.

#3: Do not use damsel fish to cycle your tank.

Damselfish are aggressive fish and when you try to remove them, they are near impossible to catch. Plus, putting a fish through a full tank cycle is like asking someone to live in a dust storm 24/7: They’ll live through it, but doing so is its own form of torture.

Leave the damsels out of your tank and do this instead.

#4: Do not put Xenia in your tank.

This coral can overtake a tank in no time. You might be able to keep in under control by trimming it every week, but seriously, there are better ways to spend your time.

#5: Do not run a tank without a protein skimmer.

Tank dabbler, reef enthusiast, reef junkie, it doesn’t matter, protein skimmers are necessary pieces of equipment.

#6: Do not use only one type of food.

Like humans, fish need a variety of food to give them the nutrients they need. So feed mysis, nori, high performance diet, cylcop-eeze and pellets on a rotational basis. I feed one type of food in the morning, and another at night.

#7: Do not add rock over time to your tank.

Save yourself the headache of mini cycles and tearing your tank apart each time you want to add rock by buying all the rock you’ll need at once. A good rule of thumb is to have one pound of live rock per gallon of tank water.

#8: Do not add live rock to your tank.

Instead, buy it dead.

#9: Do not put corals in your tank that haven’t been dipped.

Corals can carry pests that can kill your coral. Dip any and every piece of coral coming into your tank without fail.

I recommend CoralRx. You can buy it from TB Aquatics


Everyone makes mistakes and I’ve personally made several of the above.

Avoid these habits and you’ll be setting your tank up for success.

What mistakes have you made with your tank? Leave a comment and let me know.

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Comments for this article (61)

  • Kevin says:

    Good tip, thanks! Esspecially about the Xenia, its cool looking but such a pain!

  • Absolutely! Luckily I got that tip early and avoided it. Not so much on the GSP though..

  • Derek says:

    Thanks Mr Saltwater Tank! I wish I had this list when I got into the hobby. It would have saved me from some losses.

  • barry says:

    hi thanks for the great tips.unfortunatly its to late on the use dead rock tip for me . ive got a load off aptasia in my tank .

  • Barry…aptasia is never fun. Have you tried peppermint shrimp to get rid of them?

  • You are welcome.

    (Perhaps time to use these tips to start the next…bigger…tank?)

  • brendan says:

    U say dont introduce new live rock.mushrooms come attached to a rock.do i not buy mushrooms or s there another way?

  • barry says:

    no not yet ,ive read that hermits would get rid so i gave them a try.

  • Brendan-
    corals often come on small rocks or frag plugs – those are fine. I’m talking about large pieces of live rock (greater than the size of a baseball.

  • Barry…pickup a peppermint shrimp or two. They are more reliable at removing aptasia than hermits (I’ve never heard of a hermit taking down an aptasia)

  • barry says:

    ok will give it a try .i had been eying up a peppermint shrimp so now he is defanatly on my list .

  • pat says:

    great tips thanks

  • Thanks pat. Make sure you check out getting 15 minutes of 1:1 time with me for no charge: Find out more here

  • Robert says:

    I wish i would have read this sooner. I to added live rock about 60-70 lbs in a 110 still need more (thats 2 rules I broke). I noticed reciently i’ve got 2 or 3 bristle worms they dont seem to be huring anything. Are they ok to keep in my tank?

  • Robert…bristle worms are a good thing for your tank. They won’t hurt anything, but perhaps give you a bit of a sting if you happen to handle a big one!

  • poxcr says:

    Rules 7 and 8 appear to contradict each other. Can you elaborate? Thanks!

  • Sure…you decide how much LR you need and you buy it all dead, at once. Lots of people get some rock, then add more over time. It’s best to buy it all at once.

  • charles says:

    if the rock is dead, how do the “good” things get introduced into the aquarium?

  • You can introduce bacteria from a bottled product like SeaChem’s stability. Also, when you introduce corals and fish, they are bringing bacteria and other goodies into your tank.

    You can also purchase amphi and copepods to help the biodiversity of your tank.

    The key is YOU are getting to chose what gets into your tank. If you buy live rock (LR), you have no clue what you are getting.

  • john says:

    I reviewed the website you linked for the dead rock and it seems that most reviews are stating that this rock isn’t very nice. I am thinking of starting a 75 or 90 gallon reef tank in my home. What are your thoughts on these reviews?

  • John..I’m assuming you are referring to the link to the rock @ Marine Depot? Of the 2 mediocre reviews there, these people are talking about the big issue with buying any rock online – it can get broken up during shipping. Unless you local fish store sells good dead rock, then there is no way around the shipping issue. And, I see it as a risk worth taking.

    Another approach would be to buy it somewhere closer to home with hopes that with the decreased shipping time, there would be less chance for it to get broken. Bulk Reef Supply is located in the midwest USA and they have nice rock as well: http://www.MrSaltWaterTank.com/BRS_rock

  • john says:

    wow Mark you sure keep on your blog, I wasn’t expecting a response that fast thank you for the information

  • john says:

    thanks again for the tip on the rock from BRS, I got about 110 pounds for my 90g tank that I am setting up this week. funny thing though my wife seems to be as excited as me me about putting the tank in. She keeps asking when we can put in fish. Had to break the news that it may be about 4-6 weeks till we could

  • John…how big is your tank? I have something that can help depending on your tank size.

  • john says:

    mark it is 90 gallons with a model 4 perflex

  • Francisco says:

    I want to try my hand at a saltwater tank but on a small scale and i have a 10 gal tank that i used to for a freshwater tank but now sure where to start.

  • Francisco…the best thing you can do at this point is to save up more money for a larger tank. In the saltwater world, bigger is better. I’d start with a minimum of a 40 gallon tank.

  • Francisco says:

    Thank you once I have enough space and if my girlfriend lets me add another 40 gal tank i will try my hand at it. Currently i have a 40 gal freshwater tank but I love that colors and the beauty of saltwater fish.

  • Ric Johnson says:

    In your list of rules, #6 gives a list of approved foods. Any updates to that rule? Also you didn’t mention flake?

  • Ric..I’ve started to use flake food with moderate success. I’m not sold on it 100% yet.

  • Ric Johnson says:

    On ARC they automatically equate feeding flake with high phosphorus and algae blooms. Personally, I don’t see the harm in using it in moderation. My fish do love it though.

  • gregg brannigan says:

    Thanks Mark I have Two small clowns in my 28gallon nano. I have read it is not necessary to run a protein skimmer?

  • Gregg…even though you bioload is low, a protein skimmer is always a good piece of equipment to be running as it helps export waste out of your tank. I recommend them.

  • Curtis says:

    Mark, i need your help, i am 15 and have been studying fish for 2 years, and i love them, but the hobby is really expensive and i am afraid that alll of my corals and fish will die soon after i buy them? how often would i have to clean a 100 gallon reef tank starting off with a few corals and fish, i really want a fish tank but am afraid of failure, whats your best advice in general?

    Thanks Curtis…

  • Pat says:

    You said to mention newbie mistakes made – I have made several, but I beleive my glaring ones are:
    Using silica sand for substrate to save a buck. It looks fine, but I am half convinced that it was the cuase of my very loooooong bout with diatoms.
    Research every fish before adding it to your tank! No matter what your store says. I’ve bought two fish now which were supposedly ok at the store, but turned out to be too large for my tank once adult sized.

    Great site, keep up the good work!

  • Aaron says:

    Hey bud,
    If I had seen this list when I started it would have been a life saver. I started with a 75 which cracked over night(on third floor, neighbors loved me for that) and then went to 40 then 55 then 75 and now at a 110. In all steps I just moved over coral/fish and added needed LR. The cycle of each step up has killed all growth and now I am starting to think it’s time the get bigger with a move into a new house around the corner. Do you have any sound advise to someone who hasn’t seen any real heavy growth of coral and would like to see some success?

  • Aaron says:

    Fallow up,
    I do not have a reef set up per say now. No over flow. No sump. I have about 130-150lbs LR. 2 protein skimmer made for 75gal, 2 k2viper delux 250w and building my own DIY antic led setup. 2 canister filter made for 75gal and my fish load is down to a 1&1/2 foot snowflake eel and a paired up set of clowns after a bout with ick. Speaking of which now that I have no fish I’ll keep it that way to concentrat on coral. But what should be my steps to move forward and see some growth. Also about a month ago I started finally to buy all water from my store to get away from tap.

  • Aaron…coral growth is a mixture of lots of different factors and what type of coral they are. Basic ideas are stable tank parameters and good lighting

  • joey says:


    i have a 15 gal freshwater tank that im going to be changing to a salt water tank. i was just wondering about sand, if i need it and whats the best, also what are the best things to do when swithing fresh to salt water. do you totly empty the tank and clean it very well or can i just add salt the the water?

  • Jaron says:

    I have a 55 gallon reef that has been set up for 3 years. I am wanting to get into SPS corals and so far am haveing the normal beginer failures. All my tank’s levals look fine ,as in all organics at 0 with stable calcium ph and kh stabe, with the exception of phosphate which is about 5 ppm could this be causeing the death of my sps, and if it is could I run GFO in my canister filter to solve the problem. The other problem I may have is that my tank is high in minor organics so that sponges, feather worms and flame scallops do well. Should i instead set up a new tank with a more sterile enviornment.

  • Jaron says:

    Just a little explanation and an apology for the bad spelling. Many of the tips you have listed would have been nice to know for my intended SPS display, for a NPS display it is very different as I have discovered to late that my tank is now a compromise and is not really the best for either kind of animal.

  • Tetrick says:

    I have dipped any of my corals since I’ve had my 55gallon. And I’ve had it for 2yrs now. Should I dip them? The ones that I already have that is.

  • Tetrick…unless you see a pest on them, I wouldn’t re-dip your corals. By now if a pest came in on them, the pest is already in your tank.

  • Matt says:


    Is it necessary to dip soft corals as well? Such as Ricordea Mushrooms or Pipe Organs?

  • Matt says:

    Also, if you’re not supposed to use LR when setting up a saltwater tank, how do you know which color algae will grow on your base or dead rock? Is it kind of just a ‘whatever color grows, grows.’ kind of thing?

  • Jackie says:

    We have a 55 gallon saltwater tank. We have a protein skimmer that came with the tank. No matter what we do, the skimmer continually overflows. We’ve raised it up out of the water a bit, we’ve cleaned the air intake, and we rearranged the pumps in our tank – nothing works. Is it possible that our skimmer is too big for our tank?

  • Lindsey says:


    I have a few saltwater tanks and one has been running great for almost 2 years now with no problems. However, i have a new 40 Gallon tank and i had a damsel and a coral beauty and a living rock in that tank and really wanted some coral. So, i talked to the man at the saltwater store and he gave me some PurpleUp for the tank and told me to put a 1/4 of a capful in the tank everynight for a week or so before i get the coral so the coral will live when i get it. Well we did that and then we added the coral and a foxfish rabbitfish to the tank and the tank started to grow algae immediately, and the foxfish died 2 days after we had it, and our coral beauty that we`ve had for a few months died just yesterday and now even one of the arms of the coral is slightly a lighter color and hanging way higher then the others. So, my question to you is what does all this mean? And what should I do to get my tank back to running great again?

  • Lindsey…unfortunately your local fish store has sold you a bottle of snake oil for your tank. Dosing purple up won’t do anything that will magically make your coral live.

    Did you test your tank parameters after the fish died? Ie…test ammonia, nitrite, nitrate?

  • Mason Howell says:

    If I buy rock dead how do I make it live rock?

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