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Chasing Alk


LongDoggy

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I've got a Biocube 14 with a fairly heavy stocking of SPS and LPS. The tank is over 4 years old.

I do water changes with 1-2 gallons of Poland spring distilled water and Reef Crystals salt mix.

 

I've been noticing that over the past two years I've been testing all, i am always low. Around 5-6 dkh depending on if I am dosing.

 

Sometimes I will dose with Kent two part nano reef A & B. Lately I've been dosing with Kent Pro Buffer dKH because I don't want my cal to go too high in an attempt to raise Alk; (I have had my cal over 540 from using the two part A&B.

This was before I was measuring Alk so so data there to use.

 

My water before dosing was:

Cal: 360-380

Alk: 5.1 - 5.3

 

After a week of dosing Kent dKH buffer and a good water change:

Cal: 400-420

Alk: 6

 

I figured I'd test my mixed water that's been running in a bucket for two days (water change tomorrow).

Cal: 420

Alk: 4.5

 

Is this a known issue with reef crystals? Is it my distilled water? Should I dose something else?

I thought of using kalkwasser in my ATO.

 

Help? Thoughts? Advice?

Am I just chasing numbers?

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Well first off, I might suspect bad reagent on the kit or something since reef crystals should be mixing at at least twice that much alk. Have you confirmed the alk numbers with another kit? If the alk numbers are accurate its a pretty serious issue, and not just chasing numbers.

 

If its not the kit, your salt is a bad batch, I'd call them and see if there's any recourse for you.

 

If the salt was mixing right but you couldn't keep alkalinity up, I'd check your sand bed to see if its precipitating out and forming rocks in there; but that doesn't seem to be the issue with it mixing so low.

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chipmunkofdoom2

What's your Mg? Have you ever tested it? Most salt mixes are very low on Mg. I use TMPR and it consistently mixes up to 1125ppm Mg, 425ppm Ca and 7.5 dKh alkalinity. Ca and Alk are good, Mg is not. If your magnesium isn't high enough, your calcium and carbonate (alkalinity) will precipitate out (read: you'll dose and dose and dose, and your levels will never rise or stay stable).

 

No, you're not chasing numbers. I wouldn't run alkalinity below 7. That's natural sea water and I'd at least shoot for that.

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Well first off, I might suspect bad reagent on the kit or something since reef crystals should be mixing at at least twice that much alk. Have you confirmed the alk numbers with another kit? If the alk numbers are accurate its a pretty serious issue, and not just chasing numbers.

 

If its not the kit, your salt is a bad batch, I'd call them and see if there's any recourse for you.

 

If the salt was mixing right but you couldn't keep alkalinity up, I'd check your sand bed to see if its precipitating out and forming rocks in there; but that doesn't seem to be the issue with it mixing so low.

Hmmm. Interesting about the salt being a bad batch. Is it possible that over time the mix goes bad? I've had this bag for about a year or maybe a little over. I keep it sealed as well as I can and in my garage. It did get some moisture in the summer and I had to break it up a little so it was not a big block or Salt mix.

 

 

I am using the Salfert test kit which came with a testing/calibration fluid to be measured at 6.7 dkh. It tested 6.7 on the dot so I don't think it's my kit.

 

I also don't think it's in my Sandbed since my fresh mixed water actually tested lower than my in tank water (4.5 and 5.7-6.0 respectively).

What's your Mg? Have you ever tested it? Most salt mixes are very low on Mg. I use TMPR and it consistently mixes up to 1125ppm Mg, 425ppm Ca and 7.5 dKh alkalinity. Ca and Alk are good, Mg is not. If your magnesium isn't high enough, your calcium and carbonate (alkalinity) will precipitate out (read: you'll dose and dose and dose, and your levels will never rise or stay stable).

 

No, you're not chasing numbers. I wouldn't run alkalinity below 7. That's natural sea water and I'd at least shoot for that.

I've never tested Mg. the fast my water is low to start after the mix makes me think something is wrong with the salt.

Thoughts?

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Well if the calibration fluid test is coming back right then the test is *probably* fine. It might still make sense to just pop by your LFS see if they'll test the alkalinity of your fresh mixed water to double check. But it does sound like you've got a bad batch of salt. Sometimes the separate components in the salt can separate in the container to where a batch mixed from the top has different levels than a batch mixed elsewhere, but this sounds like its been a consistent reoccurring problem.

 

While bad salt explains the poor initial levels, that wouldn't explain not being able to dose it up, unless of course as chipmunk pointed out the Mg is also poor in this batch. I'd see what your Mg is and check out your sand for big lumps.

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Well if the calibration fluid test is coming back right then the test is *probably* fine. It might still make sense to just pop by your LFS see if they'll test the alkalinity of your fresh mixed water to double check. But it does sound like you've got a bad batch of salt. Sometimes the separate components in the salt can separate in the container to where a batch mixed from the top has different levels than a batch mixed elsewhere, but this sounds like its been a consistent reoccurring problem.

 

While bad salt explains the poor initial levels, that wouldn't explain not being able to dose it up, unless of course as chipmunk pointed out the Mg is also poor in this batch. I'd see what your Mg is and check out your sand for big lumps.

Well I do have big lumps in the sand. I try to keep them broken up.

I will pick up a Mg test kit to see what that looks like later this week.

 

I also just emailed the Instand Ocean Support group. Let see what they come back with.

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I remember a few threads where people had problems with chronically low alkalinity that wouldn't respond to dosing being caused by the abiotic precipitation of CaCO3 into the sand bed forming essentially large rocks. I'd see if you can find a couple of those threads and see how it was resolved. If you're getting lumps like that this might be a factor.

 

Definitely check Mg too as its very straightforward to identify and fix if its out of whack.

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i've always had low alkalinity levels myself (4.5-7 range).

turns out my magnesium levels were also low (1200 range) and no matter how much i dosed for alkalinity it wouldn't raise higher than 7.

as soon as i increased my mg levels, the alkalinity jumped to the 7-8 range.

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I remember a few threads where people had problems with chronically low alkalinity that wouldn't respond to dosing being caused by the abiotic precipitation of CaCO3 into the sand bed forming essentially large rocks. I'd see if you can find a couple of those threads and see how it was resolved. If you're getting lumps like that this might be a factor.

 

Definitely check Mg too as its very straightforward to identify and fix if its out of whack.

 

Don't think k I am forming large rocks. I'd probably notice in the nano.

Mg is going to be checked though.

i've always had low alkalinity levels myself (4.5-7 range).

turns out my magnesium levels were also low (1200 range) and no matter how much i dosed for alkalinity it wouldn't raise higher than 7.

as soon as i increased my mg levels, the alkalinity jumped to the 7-8 range.

I think we're onto something here. This sounds to be exactly my problem. But I won't know until I check the Mg. I'll be buying a test kit soon and probably some dosing formula also to bring back up.

 

This sounds like it will solve my in tank issue; but does not answer my issue with my fresh mixed water. Still awaiting reply from Instand Ocean regarding the low measurement in my Reef Crystals. I should not have to dose right after mixing.

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chipmunkofdoom2

I wouldn't call the salt bad simply because the Alk/Ca is low upon mixing. You mention that your mixed the salt and let it stand for two days before testing, and got a Ca of 420ppm and Alk of 4.5 dKh. Unless you know for a fact that your Mg is between 1,300ppm and 1,400ppm, this test doesn't really prove much. Two days is a lot of time for calcium to join up with carbonate molecules in the water and precipitate out.

 

Here is how I would handle it. First, get a Mg test kit. Second, test your tank and your newly mixed saltwater's Mg levels. Testing the tank is pretty straightforward, just test it. To test your newly mixed saltwater, mix up a batch to 35ppt salinity and test. Be sure to mix up your salt mix by shaking the bucket or manually stirring the salt mix first. Mix up the new water slowly over a few hours and let it sit for an hour or two, or until all of the salt is dissolved. Then test the Mg. I suspect you'll find it's very low. If you want to get really thorough, test the Alk and Ca as well, then retest again in a few days. If the Mg is low, you should see the Alk and Ca levels drop over the next few days.

 

An important note about mixing the salt mix. If you haven't been doing this all along, you may want to consider replacing it. Salt mix is not a uniform substance. There are salt crystals, calcium/carbonate/magnesium powders, trace element powders, etc in the bucket. All of these substances have different sizes and weights, which means that with shipping certain molecules will settle to the bottom, and some will rise to the top due to these size/weight differences. It could be that your salt mix separated and that you used a lot of one of these molecules early on. If that's the case, the mix may be terribly unbalanced and may never even out.

 

I would be cautious to call a salt mix "bad". There's lots of talk on forums about salt mixes "going bad" or "getting a bad batch", and I have a really hard time believing that salt mixes are as bad as often as us hobbyists say they are. I'd more often attribute this to user error.

 

TL;DR: get a magnesium kit. Low Mg could be your problem, and there may not be any other signs of it being low other than low Ca/Alk.

 

TL;DR the TL;DR:

 

Watch this video from BRS:

 

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I wouldn't call the salt bad simply because the Alk/Ca is low upon mixing. You mention that your mixed the salt and let it stand for two days before testing, and got a Ca of 420ppm and Alk of 4.5 dKh. Unless you know for a fact that your Mg is between 1,300ppm and 1,400ppm, this test doesn't really prove much. Two days is a lot of time for calcium to join up with carbonate molecules in the water and precipitate out.

 

Here is how I would handle it. First, get a Mg test kit. Second, test your tank and your newly mixed saltwater's Mg levels. Testing the tank is pretty straightforward, just test it. To test your newly mixed saltwater, mix up a batch to 35ppt salinity and test. Be sure to mix up your salt mix by shaking the bucket or manually stirring the salt mix first. Mix up the new water slowly over a few hours and let it sit for an hour or two, or until all of the salt is dissolved. Then test the Mg. I suspect you'll find it's very low. If you want to get really thorough, test the Alk and Ca as well, then retest again in a few days. If the Mg is low, you should see the Alk and Ca levels drop over the next few days.

 

An important note about mixing the salt mix. If you haven't been doing this all along, you may want to consider replacing it. Salt mix is not a uniform substance. There are salt crystals, calcium/carbonate/magnesium powders, trace element powders, etc in the bucket. All of these substances have different sizes and weights, which means that with shipping certain molecules will settle to the bottom, and some will rise to the top due to these size/weight differences. It could be that your salt mix separated and that you used a lot of one of these molecules early on. If that's the case, the mix may be terribly unbalanced and may never even out.

 

I would be cautious to call a salt mix "bad". There's lots of talk on forums about salt mixes "going bad" or "getting a bad batch", and I have a really hard time believing that salt mixes are as bad as often as us hobbyists say they are. I'd more often attribute this to user error.

 

TL;DR: get a magnesium kit. Low Mg could be your problem, and there may not be any other signs of it being low other than low Ca/Alk.

 

TL;DR the TL;DR:

 

Watch this video from BRS:

 

 

I'm going to have to disagree with this here. There's no reason the alkalinity would precipitate out in a couple days if all the levels were correct. Think about it. What would happen to our tanks which are kept hotter, and have tons more sites for seed crystals?

 

I do agree about mixing the salt container, as I said earlier.

 

Really its hard to make a definitive conclusion until we get Mg numbers back.

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chipmunkofdoom2

 

I'm going to have to disagree with this here. There's no reason the alkalinity would precipitate out in a couple days if all the levels were correct.

 

 

Well.. I mean, yeah there is, low Mg. That's the one "level" that we don't know is correct, and it could be causing the OP's problem in both the new saltwater and the display.

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I did not think any levels would precipitate out of the freshly mixed water after a few days since there is nothing in the bucket pulling from the supply.

Also, I did not consider the mix separated in the bag. I buy the reef crystals box that has the plastic bag of mix inside. It's very possible this has separated. Currently I have maybe about 10-20 gallons of mix left that is about 1/2 powder and 1/2 two large solidified blocks of mix. I'll do my best to break up and mix up to see if that does anything. At the least; I'll blend what I have left.

 

Later on, I'll grab a Mg test kit and report back with findings.

Should I buy a bottle of Mg to dose while I am there? It seems likely.

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Well.. I mean, yeah there is, low Mg. That's the one "level" that we don't know is correct, and it could be causing the OP's problem in both the new saltwater and the display.

 

Which we don't know if its low or not. And you originally just said it will precipitate out in a couple days if you keep it in a bucket.

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Well found the problem. It's my mix. I bought a new box of reef crystals, mixed and tested the following day.

Alk is 10.2dkh

 

About to do a 20% WC

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Last box of RC I bought tested at 9 dkh. Instant ocean tested at 11.5

 

Go figure that one since RC is supposed to be jacked up with higher amounts of everything.

 

Personally I'd rather have a salt mix test with lower dKH and higher calcium, magnesium.

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^^^^^^^^^^

That's why I stopped using RC, alk was too high and threw everything out of balance. Pick a salt mix that's as close to NSW and forget about it.

Just my two pennies.

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I use Aqua Vitro Salinity and love it. I don't have to alter my dosing after a water change (like I used to using RC) and my parameters are within range of NSW. I was going to use Tropic Marin, but decided to give Salinity a try and haven't looked back.

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