Water chemistry and total confusion

[rjs5134]

When you guys are tired of me and this topic, let me know... Whenever things seem better, they end of worse.

I'm still struggling with alkalinity, calcium and magnesium. The other piece, Ph, seems just fine and stable at 8.2. A review of my aquarium log will show the rollercoaster of these 3 but to summarize:

Calcium is almost always on the low side, just under 400.
Magnesium has been at or above 1500ppm for a long time.
Alkalinity was low, around 7.0-8.0dKH for a while.
Even with dosing supplements I couldn't get these to change significantly at least not for any length of time.

A change of salts showed temporary improvement and alot of promise but now the numbers are worse than ever:
Magnesium dropped to 930ppm.
Calcium dipped to 260ppm.
Alkalinity plummeted to 5.8dKH.

I read Randy Holmes Farley's article from Reefkeeping again, and although he dislikes question like this, is this possible? In just a few days?? I don't have alot of calcium carbonate absorbing life forms, not even alot of corraline algae(because of this problem i presume), yet the numbers dropped from reasonable to terrible in about 4 days.

What gives??

[Ninong]

Even with dosing supplements...

What exactly are you dosing and how?

A change of salts showed temporary improvement and alot of promise but now the numbers are worse than ever

What brand were you using, what brand are you now using, when did you make the switch?

Magnesium dropped to 930ppm.

Not a serious concern at this level but you will want to get it to at least 1100 ppm, with an eventual goal of approximately NSW concentration of 1285 ppm. Anything between 1100 ppm to 1500 ppm should be acceptable.

Calcium dipped to 260ppm.

This is on the low side and you will definitely want to get this up above 350 ppm with an eventual goal in the 425-475 ppm range.

Alkalinity plummeted to 5.8dKH.

This is a little too low. NSW alk = 7 dKH and most people like to maintain it above NSW, say at least 8-9 dKH. I think 10-12 dKH is even better. Exactly what are your pH measurements when you measured 5.8 dKH alk? You should measure pH early in the morning just before your lights come on and then again late in the afternoon of the same day just before your main lights go off. You should see a lower reading in the early morning compared to the late afternoon reading.

What gives??

I don't know but I suspect it's related to something you did.

[charlie]

The calcium and alkalinity balance is also alot of personal preference. Ninong liked his levels as he stated. I personally like between 400 and 420, but you must balance your alkalinity accordingly. JMHO

[rjs5134]

Ninong, I was using IO which had an alkalinity of 10.4dKH before being added to the tank. Two days later the tank was around 6.0-7.0. I was dosing Kent's Superbuffer dKH and Kent's Liquid Calcium. After several days I got the levels up higher, but after a day or two later(not dosing) they were right back to where they started. Magnesium never came below 1500ppm.

I switched from IO to Crystal Seas.

I'm not overly concerned about the Mg level, but curious that it dropped below 1500ppm for the first time... and it dropped quite a bit.

Funny that Ca dropped alot also. It's now at it's lowest point in 3 years.

Alkalinity is my biggest concern, it's also at it's lowest point ever. I do understand(realize) the relationships between the 3 and it's more the variability that confuses me.

Ph has not been a problem. It's been a pretty steady 8.2-8.3 depending on time of day.

Right now I'd just like to get to a more acceptable and stable level, then I'll worry about preferences. I'd be happy with 9.0dKH, 380ppm Ca, and 1100ppm Mg. I think my coral problems are related to this issue.

Thanks for the help.

[charlie]

Do you drip Kalk at all?

[rjs5134]

I have been dripping Kalk about every other night for the last 2 or 3 weeks except on weekends. I haven't been dripping alot(about 36oz), I only have a few small stony corals.

[Ninong]

I have no personal experience with the two Kent's products you are using. I started out with B-Ionic's two-component product for building up calcium and alkalinity. After about six weeks (or maybe a little longer), my calcium levels were above 400 ppm, so I switched to dripping limewater (Kalkwasser) nightly to replace evaporation. I found that the limewater did a good job of maintaining calcium and alkalinity but did almost nothing for magnesium, which I had to supplement every several weeks using ESV's Mg supplement, which I believe is mainly magnesium chloride.

As mentioned previously in this forum and others, some hobbyists have reported problems when switching from Instant Ocean to Crystal Seas. I started with Crystal Seas Bioassay Formula and never used anything else. I did not have any problems. Many people (including Dr. Mac) have switched from Instant Ocean to Crystal Seas without any significant problems but many people did report significant problems. We have never been able to figure out why some people experienced problems making that particular switch. It's important to point out that the only switch that has been reported by many hobbyists to cause problems is from Instant Ocean to Crystal Seas.

Ignoring the potential for problems possibly related to switching between these two brands, there are steps you can take to make sure your salt mix is not part of your problem. It is possible to receive 'bad' batches of salt. Many people have reported 'bad' batches of Instant Ocean over the years. There are several threads on this topic on Reef Central. What I would suggest -- and this applies to any brand of salt mix -- is that you mix the contents of the container (bucket, bag, box, whatever) the salt came in to take care of any possibility of settlement causing a problem. Then I suggest that you mix up a test batch of saltwater. It doesn't have to be very large, whatever you feel comfortable with. You could even start with just one liter if that's what you feel like doing but most people would probably make up a few gallons.

If you want to determine if your salt mix is mixing up to NSW salinity, you should measure 35 grams of salt mix and add that to 965 ml of freshwater (preferably R.O./D.I. or distilled water). This should give you 35 PSU (practical salinity units -- the same as ppt) but it almost never does. Depending on the brand, you almost always come up short and have to add a little more salt mix. One of the variables is the moisture content of the salt mix. You should use a refractometer to measure the salinity. Remember that the most common refractometers used by hobbyists are calibrated for saltwater, not seawater. It your refractometer measures 0 ppt when you test distilled water, then you will need to read approximately 1.026 SG or slightly above 36 ppt on the scale if you want 35 ppt salinity. I never bothered with the exact correction and simply read 36 ppt salinity on the refractometer as being equivalent to 35 ppt (actually it's equivalent to slightly less than 35 ppt.)

Why is this important? It's important because if you are mixing up your saltwater to only 31 or 32 ppt instead of 35 ppt, you won't get anywhere close to NSW levels of calcium, magnesium, etc., unless your particular mix is very high in those elements to begin with. In other words, someone who follows the recommendations of some of the salt manufacturers and mixes up his saltwater to 1.022 SG isn't going to get calcium numbers anywhere close to 400 ppm with Instant Ocean salt. In fact, I would be surprised if they even got 320 ppm Ca.

My testing of Crystal Seas Bioassay salt three or four years back gave me readings of approximately 400 ppm Ca, 1150 ppm Mg, 14 dKH alk, at 35 ppt salinity. I always measured the Mg to be a little bit on the low side and the alk to be a little bit on the high side. YMMV and they have made changes to their formulation in the past 18 months according to information I received.

Here's what I would suggest you do right now. I would start by testing the salinity of your tankwater. Let's see what you get there. If your salinity is below normal (35 ppt), then your calcium will be below normal. Then I would gradually raise the salinity to 35 ppt by using saltwater for evaporation replacement.

I would also test a freshly made up batch of saltwater after allowing it to age for about 24 hours. You can check the salinity within an hour to see if you need to add more salt mix but I wouldn't bother testing for calcium, etc., until the saltwater has aged at least 24 hours. That's just the way I did it. And I never used saltwater until after it had aged at least three days unless it was an emergency.

[rjs5134]

Thanks Ninong, I ordered 2 large boxes of Crystal Seas before(I think) I knew there was a potential for a problem with IO. I figured if you, Dr.Mac and Gene used CS, it should be a good choice for me.

My refractometer is calibrated with RO/DI water therefore I mixed it to 1.0026. I also tested this:
Calcium 400ppm
Magnesium 1400ppm
Alkalinity 10.4dKH

WOW would I be happy with these levels.

Anyhow, I didn't wait to read your reply, instead I performed a large water change, 20+/- gallons. The water was prepared 4 days ago and has been mixing since. The new display tank parameters are:
Calcium 360ppm
Magnesium 1350ppm
Alkalinity 8.3dKH

I would even be happy with these if they were stable,

The Ph is up to 8.3 from 8.2, which makes sense since it is much later in the day.

Now if I dosed Kalk each day would that help maintain this or should I be taking more corrective actions first?

[Ninong]

Limewater (Kalkwasser) is a balanced additive as respects calcium and alkalinity. It will usually maintain proper calcium and alkalinity but it's not the fastest way in the world to raise these parameters. And it may not be adequate by itself once the tank is heavily stocked with corals. However, it should be adequate in your situation and it should gradually raise both your calcium and alkalinity levels.

Dosing limewater for all evaporation replacement should be sufficient for your situation and it should gradually raise both calcium and alkalinity because your tank is not heavily stocked. If you drip limewater every night to replace evaporated water, you may not need to dose anything else other than a magnesium supplement every now and then, which really depends on a lot on how often you do water changes.

Virtually all of the reported problems associated with switching from IO to CS involved coral bleaching, which is why I always caution people to go very slow when making this particular switch. An initial 5% water change using CS and then wait at least two or three weeks before a second water change of maybe 5%. I don't know why some people had problems but enough of them posted about it that I think we should exercise caution when making this switch. Dr. Mac used to use Instant Ocean but he switched his entire operation to Crystal Seas a few years ago. For one thing, his business is very close to the place where they make Crystal Seas and he gets a very good price on it.

[rjs5134]

Ninong, this is where we're at now... I've dosed Kalk almost every night for the last 2 months or so and gave things a little time to settle after the salt switch. Coral frags look good, even showing some growth, but... the BTA hasn't looked great lately. I performed a water test today and this is how it looked:

Ph 8.5
Mg 1400ppm
Ca 450ppm
Alk 5.6dKh using Lamotte, 6.4 using Salifert.

I'm shocked to say the least, I dosed a little more Kalk last night than in the past. I really expected to see the Alk higher, not lower. I also expected to see the Mg a little lower since I haven't done a water change in a couple of weeks. I'm going to drip the usual amount of Kalk tonight, but how do I raise Alk without raising Ph and Ca further?

Thanks.

[Ninong]

Mix 1/2 level teaspoon of baking soda into a cup of tankwater and then pour that into your sump or into a stream of water from a powerhead, etc. Do that every day for five days straight and then retest. Your alkalinity should read close to 8 dKH (LaMotte).