How do you keep track of pH, KH, Ca and Mg?

[A.ocellaris]

Hi,

 

I've been reading about how important is to keep parameters stable, but it's very hard to know where you currently are with normal test kits like API or Salifert. Like I can be testing pH 2-4 times a day but the API scale is not helpful. The same with KH, I would like to know how it changes by the day so that I know when to worry and prevent any stressful situation to my creatures.

 

Is there a device that you guys use to keep track of these parameters? Are they very expensive? Is it possible to log the results maybe every hour? I feel like I want to know what's happening in my tank . My temp and salinity (thanks to the ATO system) are very stable. I am not sure about my pH (mostly 8.0) and I know it changes during the day, but how much of a change is the question. 

 

pd. I am kind of new at reef chemistry Reading as much as I can...

 

Thanks

Edited May 7, 2018 by A.ocellaris

[A.ocellaris]

I just read this... wow !

 

How much buffering does your tank need? Most aquarium buffering capacity test kits actually measure KH. The larger the KH, the more resistant to pH changes your water will be. 

 

 

I didn't even know KH was the "buffer"

[Origami]

Hi,

 

I've been reading about how important is to keep parameters stable, but it's very hard to know where you currently are with normal test kits like API or Salifert. Like I can be testing pH 2-4 times a day but the API scale is not helpful. The same with KH, I would like to know how it changes by the day so that I know when to worry and prevent any stressful situation to my creatures.

 

Is there a device that you guys use to keep track of these parameters? Are they very expensive? Is it possible to log the results maybe every hour? I feel like I want to know what's happening in my tank . My temp and salinity (thanks to the ATO system) are very stable. I am not sure about my pH (mostly 8.0) and I know it changes during the day, but how much of a change is the question. 

 

pd. I am kind of new at reef chemistry Reading as much as I can...

 

Thanks

 

As somebody new to the hobby, you'll probably feel compelled to test really often. When you get more seasoned, you'll test far less. Trust me. When I started out, I probably tested a couple of times a day. Nowadays, I may test a couple of times a month. Many of us have our favorite test kits. Salifert is a good name. Hanna makes a good meter used for alkalinity. I also have their ULR phosphate meter but don't use it often. I'll also use Red Sea Pro for calcium and magnesium. I also use an electronic meter called an iDip Exact to measure a bunch of parameters, but I'm still in the process of having full confidence in it.

 

As for "keeping track," I simply write it down on a notepad that I keep near the tank. I have a shortform notation that I use that goes something like this 

<date> <time> <test> <manufacturer> <reading>

 

For example

4/11/18 21:15 ALK HAN 167

is short for "Alkalinity test on 4/11 at 9:15 PM using my Hanna alkalinity checker, 167 ppm reading."

 

I'm going to recommend that you read a basic tutorial on the composition of seawater by Randy Holmes-Farley, a chemist that has written a lot on various hobby-related chemistry topics over the years. Then read his article on Reef Aquarium Water Parameters. Get this under your belt and come back with questions.

 

I'm not terribly concerned with pH. It's going to be what it is. My primary concerns will be centered on calcium, alkalinity, and to a lesser extent, magnesium. All three of these are consumed by hard coral growth and need to be replaced either by dosing routines or water changes.

 

I monitor my pH, though, with an aquarium controller, though. It actually keeps records of it and plots it out over time. Know this about pH - it cycles daily. It will be lowest first thing in the morning, before the lights go on and will tend to climb through the day until the lights go out in what we call a diurnal cycle. pH can shift as much as 0.3 points or more over this cycle.

 

Alkalinity is what you're calling KH. The KH is a German abbreviation for "carbonate hardness." It's commonly measured in units of dKH (degrees of carbonate hardness) or, alternately, in units of milliequivalents per liter (meq/l) or ppm of calcium carbonate equivalents. Different test kits will give you different measures but they all relate to one another in this fashion: 1 meq/liter = 2.8 dKH = 50 ppm CaCO3 equivalents. Alkalinity is consumed by the calcification process that hard corals use to lay down their skeleton. It's the "carbonate" part of "calcium carbonate." A typical reef tank runs at 8-10 dKH. In an established tank, alkalinity can drop 2-3 dKH in a day.

 

Calcium is the other main part that makes up a coral skeleton. Typical range for it in a reef tank are 430-460 ppm.

 

Magnesium levels are typically around 1250 - 1400 ppm. Magnesium sometimes replaces some calcium in coral skeletons and is needed to keep the supersaturated calcium and alkalinity in seawater from forming a spontaneously precipitate - a process that we call abiotic precipitation.

[AlanM]

I keep track of historical parameters with aquaticlog.com.  It can read pH and temp from my controller and I enter other tests as I do them. 

 

I like Red Sea Pro for Ca and Salifert for Mg.  I use Hanna checker for alkalinity and also their ultra low range phosphate checker for phosphate.  I use Red Sea Pro for nitrate when I'm testing it, but I don't do that very often.  

[madweazl]

I use aquaticlog to track trends as well. In general, I couldnt care less what a single test result reads (within reason). I perform six tests every Saturday and perform a 12% water change on Sunday, they are: salinity, alkalinity, calcium, magnesium, phosphate, and nitrate. If values are out of the norm I make no changes until I see what the values are the next week. If alkalinity is outside the norm, I'll check it midweek as well just to see if it was anomaly. I never make a change off a single test result unless it is way outside "normal" and I verify with another test (I dont think this has ever happened in the past two years but I may be mistaken). 

[Matt LeBaron]

Good advise from everyone above. To what Origami said once your tank is well established you will find you do not need to test as often unless you are trying to correct a parameter. Here's my example of parameter correction:

 

So I recently checked my Alk after not doing so for *far* to long (learn a lesson from me) and found it to be very low, my SPS frags had turned into large colonies and were depleting my Alk at a much faster pace. (It was an "I'm an idiot, of course they are" moment for me but hindsight and all that) So I started manually dosing Alk and slowly increasing my automated dosing to where I am now very close to having my automated dosing back to the point where it is meeting my corals needs but I have done it slowly over weeks with testing daily to make sure I was not over correcting. Slow and steady, everything in this hobby needs to be slow and steady, my corals were not growing as quickly but were still more than healthy despite the low Alk because it declined slowly over time as they grew bigger but my dosing did not keep up.

 

*Also want to note just for completeness that I have also been monitoring my Mag and Calc on a daily basis during this process because all three parameters are linked, I just can't increase the Alk without those other two parameters being monitored also.

[zygote2k]

Less is more.

Test weekly and record the values before every water change.

Establish a baseline and go from there.

[Keannis]

I use an app called Aquarium Note - lets you keep track of all the parameters, will display graphs over time, has built in timers for the tests, and lets you log equipment/livestock/significant events if you so wish. It's been really useful for me. I'm going to look into Aquatic Log though, it looks more full-featured and having a website version of everything would be so nice... 

Edited May 9, 2018 by Keannis

[zygote2k]

Write it down on paper. It’s free and you can easily look back at the past.

[Matt LeBaron]

What is this paper thing you speak of? How often does it require charging and is it a locked down format?

 

I lose stuff in my fish room/workshop too easily, I record my reading on my iPad because I'm less likely to loose the $400 electronic than a piece of paper.

[A.ocellaris]

Thank you all. This is great information. I just signed up for a aquaticlog account and helps me keep track of test results. I do not have SPS coral so I think I should stick to regular test kits for now. My pH is 8 every time I test it and I does not go up. I am hesitant to use additives for this since I've read a pH of 8 is not bad, specially in closed apts.

 

 

In a near future I would like to move so more real-time monitoring of my tank.

[Origami]

Thank you all. This is great information. I just signed up for a aquaticlog account and helps me keep track of test results. I do not have SPS coral so I think I should stick to regular test kits for now. My pH is 8 every time I test it and I does not go up. I am hesitant to use additives for this since I've read a pH of 8 is not bad, specially in closed apts.

 

 

In a near future I would like to move so more real-time monitoring of my tank.

 

pH will / should change between the time the lights first come on in the morning to right after they go off at night. The reason for the shift is that photosynthesizing organisms (plants, algae, and most corals) will use CO2 up during the "day" (thereby raising the pH) and release CO2 at night (lowering the pH). Your pH should be highest, therefore, just as the lights go out in the evening. 

[gmerek2]

I like your enthusiasm for testing. Keep it up. It helps a lot. And also test the tests. Sometimes stuff goes bad or you start doing it wrong.

Edited May 16, 2018 by gmerek2

[A.ocellaris]

So I went shopping and got some good test kits! After reading about different test pros and cons I got Hanna instruments for Alkalinity and Phosphate, and Salifert for Mg and Nitrates. Results are attached. They look good!

 

I am still testing pH with API

Edited May 18, 2018 by A.ocellaris

[A.ocellaris]

Hey!

 

So during the past 2 months I've noticed that my Mg gets depleted faster than Ca. KH also goes down but since this is found in less concentration it's expected. What do you recommend for increasing Mg? I use RedSea REEF FOUNDATION, but looks like it wont be the best option in the long term.

[BtmDweller]

After reading and all the chem lessons. Test the same time of day or night. Realize it will shift slightly through the day/night. Make small changes, try to get it close to what you desire, realize it won’t be perfect. Think of stability day to day at the same time of testing. Use a quality doser.

 

— my opinions

 

 

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[Origami]

Magnesium is present at levels 4 to 5x that of calcium. Normally it's used up at 2 to 5 percent of the rate of calcium, though. It's quite unusual for it to be used up faster by normal processes. What are you using to measure salinity? What is your salinity? Have you bothered to test your freshly mixed change water? And finally, you're not using a kalk reactor by chance, are you?

 

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[A.ocellaris]

Magnesium is present at levels 4 to 5x that of calcium. Normally it's used up at 2 to 5 percent of the rate of calcium, though. It's quite unusual for it to be used up faster by normal processes. What are you using to measure salinity? What is your salinity? Have you bothered to test your freshly mixed change water? And finally, you're not using a kalk reactor by chance, are you?

 

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That's why I was curious about this issue. I use a calibrated refractometer and I keep salinity about 1.025. I have not tested fresh mixed water for Magnesium, but will do it next time and no kalk reactor. I also use Salifert Mg test kit.

Edited August 14, 2018 by A.ocellaris

[Origami]

When I get unexpected test results, I'll test again (suspecting user error). And, if I still don't get results that I feel are easily explained, then I'll grab another test kit (suspecting test kit error).

 

There's not much that will cause magnesium to deplete really fast. However, running tank water through a kalk reactor will result in magnesium hydroxide being precipitated out, thereby reducing ionic magnesium from the water. This would occur if somebody made a mistake in how they set up the kalk reactor. This isn't your case, though. But it's why I asked the question.

 

By the way, to answer one of your original questions: To supplement magnesium, you can use magnesium chloride or a blend of magnesium chloride and magnesium sulfate. The latter is also known more commonly as Epsom Salts.

 

I like this reef chemistry calculator and have used it for years. After putting in your parameters, you can select the product that you want to use as a supplement and it'll tell you how much to use and give brief instructions of how to dose it. Because the magnesium ion is so light compared to the hydrated magnesium chloride, don't be surprised if you have to add what seems like a lot. 

[A.ocellaris]

Thanks!

 

I tested fresh mixed saltwater and got 1200ppm! Could this be the reason? Maybe a got Instant Ocean Reef Crystals batch with low Mg.

[Origami]

1200 ppm is slightly low but could just as likely be a measurement error. Since I don't know what Mg you started out at, it's difficult to say if this is contributing to the observed decline.

 

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[madweazl]

1200 is abnormally low for Reef Crystals (would expect 1350-1400) but spot on for Instant Ocean at that salinity. What did you use to calibrate the refractometer?