Dirt-simple chemistry MUST-knows for tank health

[Sk8r]

[repeated from the Reef Discussion Forum]
I'm going to start very slow, very basic, and work toward the lesser known things.

1. your salt mix is not just salt. It's dry seawater. And that means not only salt, it's calcium, magnesium, iodine, selenium, boron---read the label on your salt mix.

2. evaporation never evaporates the minerals. It only evaporates the water.

3. animals and plants suck up part of the minerals. So TWO actions unbalance your tank---evaporation increases the mineral concentration---and animals and plants take the minerals they need and leave what they don't. This means certain minerals run lower and lower and certain ones don't---they just pile up. As you add more fresh ro/di (water that's ONLY hydrogen and oxygen, with NO minerals) your tank gets no more minerals. And your shortage of what the animals and plants are using most gets bigger and bigger. Water changes, 20% a month, replenish the missing minerals, but they're alway playing catchup.

4. Salt mixes are NOT all the same. Reef salt contains a high amount of what corals need AND what fish need. Marine salt for fish-onlies is lower in calcium and other minerals. That's why the price difference.

5. Now---the nitty gritty of chemical balance in your tank. First, the balance is set by your salt brand. The more you mess with that, the worse your water. Translation: don't go dumping supplements into your tank unless you've got the corresponding test. They don't sell these things together because they don't run out at the same rate, but your lfs should stress, with every supplement---you need a test. And you need a logbook. If you turn up a shortage, you dose until you put the RIGHT amount into your tank, with a little leeway; and you test again next week to figure out how fast that's running low. And you dose to stay in the 'good zone', NOT as make-up after your water's gone wonky. Dose to the TREND of the numbers, the way when you're balancing something in your hands, you don't let it swing way to one side before you correct it back to center. There is NO one answer to these things. Every tank is different. And staying in the center of a 'good numbers' zone is best: that gives you a little leeway in either direction.

6. THREE readings go in 'lock' to keep your water good. These three are: the alkalinity of your water, the amount of calcium in your water, and the amount of magnesium in your water. Those of you with freshwater experience are used to tracking PH. Alkalinity is the thing most reefers track. Get it between 8.3 and 9.3 on the KH scale, and don't angst over the ph.
The second reading is your Calcium level. It should be between 420 and 500. Below that---your snails' shells start dissolving. And your fish's bone and muscle suffer. The third reading is Magnesium. All you people who want coralline to grow---just keep this one at 1300. But it does a lot more than supply coralline. It LOCKS the other two readings in a 3-way balance. Keeping everything in that relationship will make everything happy.

7. Remember that business about plants and animals using up minerals? Calcium and magnesium are the ones animals use bigtime. Plants---use phosphate and nitrate. Yes, even those chemicals are useful. Plants grow like mad with phosphate. Grow them in your sump, divide the mass in half periodically and get rid of it, and you've just tossed a lot of phosphate and nitrate. That's what a fuge does. And the reason not to use conditioned tapwater? City water grows plants. Algae. A lot of it. The conditioners don't remove phosphate.

8. Dosing: you must dose to keep your calcium supply up if you have stony coral. Hand-dosing is just fine if you don't. You should be able to keep up with the mineral consumption problem if you have fish and softies, including anemones. Just stay in the target range, and do your water changes.

If you have, or want to have, stony coral, you need to get onto that calcium situation the minute you put them in the tank. They come in 'asleep'. Given good lighting (a requirement for stony coral) and correct chemistry---they'll put out a finger to feel the water. And they'll start waking up. Hungry---because they've not eaten in a while. And what they want is calcium. A lot of it. They'll suck it right out of your salt mix, until your snail shells start dissolving. So you have to put it in. 3 little coral frags can take heaping teaspoons worth of calcium supplement---daily---and at nearly twenty dollars a jar, this could get ruinously expensive. But there ARE cheap ways to give them what they need. Kalk drips are the cheapest. They can fully supply a 50-60 gallon packed reef. Above that you get into calcium reactors, which can supply much larger reefs. There is also the Balling method. And 2-Part. Tank size and coral load will determine what you need.

9. aging tank: reading all this should tell you that the older a tank gets, the more little imbalances and shortages it accumulates. Age has benefits, but it also has problems. I recommend, at least every couple of years, an aggressive program of semi-weekly 20% water changes, so you can sort of re-set the balance. It's my own notion, but I think it does a bit to replenish the things far down the list of reef-salt ingredients.

[Sytje1234]

Sk8r...............great post. Too bad they don't have "like" buttons on here. I took chemistry and biology quite a number of years ago. Funny how things slip away when you don't use it for a long length of time. These refresher reminders are awesome to me. It is basic, but something we all need to know and understand in order to keep our tanks in check and the inhabitants happy! Hey.....thanks! I also come from FW tanks, main fish were Discus. In fact they were my first fish in a tank. Ph, acidic water, certain PH's to get them to breed, etc. Definitely, not a hardy fish. Really liked them though.

Thanks for this great post! I think everytime I come on this website I learn something new.

[Ron Reefman]

Why couldn't I have found a post like this in a LFS 7 years ago when I started? It took me years to get into stoney corals and then more time to get this level of basic understanding of the chemistry. But then I didn't find RC or my local club until I had been in the hobby for 3-4 years. This really belongs in the stickies.

You really do some great posts in terms of being helpful for the newer reefers.

[thor109]

Sk8r , you should think about writing a book. A lot of people know this stuff but you have a great way of explaining it so we understand.
You would be giving the entire hobby a boost by making it easier for people to be successful reefers.

Thanks for sharing

[bnumair]

Originally Posted by thor109

Sk8r , you should think about writing a book. A lot of people know this stuff but you have a great way of explaining it so we understand.
You would be giving the entire hobby a boost by making it easier for people to be successful reefers.

Thanks for sharing

lol she is a writer by profession and a good one. Nice write up again Sk8r.

[rl225]

Very helpful. Thank you.

[avelino78]

Sk8r. I don't have an ATO and I top off daily with about a cup of water. I have a few corals and I just did a water change using Tropic Marine. I will test everything today to see where I'm at and then on Saturday night I will test to see what I have. I do a water change every week once I get those numbers you think you could give me an idea of what I should use to keep my corals and fish happy???

[Tom.B]

Brilliant post. Added this to my faves until I learn by memory what levels etc I need!!

[Sk8r]

Thanks, all.
Avelino, even a nano can top off with kalk if need be, for stony coral: just keep a lidded bucket of kalk water, dip out a cup and replace the lid...it doesn't go out of solution, but needs to be lidded. First start a log of your readings, and use that for a guide. If your water changes are keeping the levels good, that's all you need. If you're calcium-short, kalk would be a good answer for you and the best way to supply calcium to stony coral. Softies don't need anything but regular water changes.

[Sk8r]

Re the book: I do try to keep a blog that's like a how-to manual. Just go to that and rummage. It's not in any particular order, but I try to put posts that might help in there and save them.

[avelino78]

Thanks I will look into that.

[avelino78]

What kind do you suggest to buy??

Sk8r's answer: Kalk? Mrs. Wages' Pickling Lime---available at many lfs, some groceries---it's meant for making cucumber pickles. About 5.00 a 2 lb bag. Add 2 tsp per gallon to ro/di water, keep it lidded, let it replace your freshwater topoff. Note: it can't RAISE your calcium level, but it will maintain it if alk and cal are optimum. It will hold it rock solid even until the mg depletes below 1300. Test mg weekly, top off with kalk, and your 1 gallon to 60 gallon tank will NEVER go out of sync so long as the mg never falls below 1300. It's one of the most magical freebies in tank chemistry. If your tank is bigger than 60 gallons it will still work on a light coral load. But if you have a mega-tank you need more than kalk alone can do. It has to do with how many corals you can stuff in a given sized tank...and how big their appetite is. My 54 g is about as stuffed as you can get and it's doing fine.

[kawicivic]

I've never heard of issues with fish bones and snail shells getting soft due to calcium: can you direct me to any additional resources on these items? tks

Sk8r's answer: Not soft. Weak, prone to break or grow badly. Look up the function of calcium in biochemistry: it's part of the muscle cycle, including heart action, and part of the structure of bones and shell. Look up calcium deficiency in any medical text. Snail shells and hermit shells will develop holes as calcium dissolves, observable in any marine tank with chronically low calcium.

This explains it pretty well in human medicine, and fish, in this regard, work in the same way. http://www.localhealth.com/article/calcium-deficiency

[avelino78]

So I just ran my tests. I did a water change yesterday. I did three different kinds of calcium tests Hanna 401 red sea 385 API 380. KH 9.1 mag 1060. Now what I was told to wait until the day before my water change and test again to see how much was used or should I just start doing something about this now???

[Sk8r]

Start doing something about it. You'll change out only part of your water. Just start fixing it. It's not a huge deal, just something that's been wrong for a while that can be a whole lot better. Just make all changes by the bottle instructions and go slowly. NEver rush a change in a marine system unless it's a case of toxicity or no air---and this is definitely an go-slowly.

[avelino78]

Ok thanks so I will have to get something to get my mag up and then go buy some kalk thanks for the help.

[Sk8r]

Remember to get your alk and cal parameters spot-on before you start dosing kalk. That will hold them where you set them so long as you keep your mg up.

[avelino78]

Ok I will have to look into what to buy to get my levels up. Any suggestions ?? Also will it be safe to top off about a cup full of kalk into my tank?? I was readying that it can raise your ph.

[Sk8r]

Kalkwater should be fully dissolved, look about like one eyedropper of milk dissolved in a glass of water, and allowed to settle for a few hours to be sure. Then I'd add it a quarter of a cup every 15 minutes.
It comes in at a ph of 12, but drops rapidly as it hits the tank.

What I use for manual adjustment: I use the Salifert tests for alk, cal, and mg. And I use Kent Turbo Calcium for the cal, Kent DKH Buffer for the alk, and Kent Tech M for the magnesium. Remember to let the tank run for a number of hours to fully process the new dose into the rock and sand before you'll know what your levels are.

[Squidmotron]

So you're saying I won't be able to use Kalkwasser and keep up, eventually.

I have 135 gallon tank, and plan to have about 35% LPSes/SPSes. Should I purchase a calcium reactor?

[Sk8r]

Ultimately, if you want a packed reef, either a calcium reactor, ---or maybe Balling Method. I'm not familiar with that method, but it claims to handle larger tanks---you might research it and find out; also check out two-part: there's some simiilarity. But it's at least pretty sure that ultimately kalk won't keep up for you. You'll know when you've reached that limit when your kalk drip just can't maintain the levels.

[avelino78]

Ok thanks. So for a cup of water I would only use a few drops of kalk?? Once I get this I'm sure it will be easy.

[Sk8r]

It's, for starters, until your corals really start eating, 1 teaspoon kalk per gallon; go to the internet for cups-per-gallon: I think it's 16. you can get a measuring spoon that's 1/8th tsp. That would let you make up 2 gallons in a bucket, lid and save it. Ultimately, the most ro/di will EVER dissolve naturally is 2 tsp per gallon. Stir it once, lid it, and never use any white precipitation in the bottom of the bucket. Just the filmy water. When your alk and cal needs start exceeding 1 tsp per gallon, go to 2.

Those of you with larger tanks, you CAN put your ATO pump in the [lidded] bucket and adminster kalk through the ATO system.

[MaxxedMan]

What if I raised my Alkalinity from 7 to 13, CA if 450, and my mag is about 1400

Do I need to lower it since the Mag at 1400 will lock it?

[Sk8r]

Good question, maxxedman---Because everything is a bit HIGH---I'd let that 'run down' a bit and get LOW. It'll take a while, because of the high mag, but let it run out, let everything fall slightly, then THEN set the mg, and raise alk up to 8.3-9.3, the ca to 420-250, all ok;

If you're already LOW, set your mg level FIRST, to lock it, because if it isn't, you'll be pouring in stuff trying to add it faster than it can fall---so if you're LOW, start with mg, get that up, THEN raise alk, then cal.

Think of the mg, indeed, as sort of the foundation. If everything is high, let it all fall until the last of the 3 has sunk into an acceptable range, then lock the mg to a proper reading, which holds everything steady --- think of it as rather like a chock under a wheel, if you were working on something that could roll---and then fix the other two readings. If everything is already low, then kick the chock under the wheels, (raise the mg) and fix the other two. Otherwise it will all be a moving target.