Mysteriously Rising Alkalinity

[pokerdobe]

Background - I noticed that my acros kept getting bleached tips or was stning from the tip. To me, that typically denotes an alk swing. To confirm this, I kept track of my alk #'s throughout the week and it rose from 10.1 to 10.8.

 

The problem - I do not think I am dosing anything that could cause this rise in alk. I took my doser offline months ago and even disconnected the doser from the dosing containers. I checked my RODI water and there is no alkalinity there.

 

I am not running carbon, GFO, carbon dosing, biopellets.

 

What could be causing my rise in alk? It's killing my acros slowly.

[dandelion]

Did you add any new sand or live rocks recently?

 

Background - I noticed that my acros kept getting bleached tips or was stning from the tip. To me, that typically denotes an alk swing. To confirm this, I kept track of my alk #'s throughout the week and it rose from 10.1 to 10.8.

 

The problem - I do not think I am dosing anything that could cause this rise in alk. I took my doser offline months ago and even disconnected the doser from the dosing containers. I checked my RODI water and there is no alkalinity there.

 

I am not running carbon, GFO, carbon dosing, biopellets.

 

What could be causing my rise in alk? It's killing my acros slowly.

[pokerdobe]

No new sand or live rock. Last time sand and lr was added was Jan 2016.

 

Did you add any new sand or live rocks recently?

 

[dandelion]

Did you accidentally put some salt into your top off water? What else are you dosing?

 

No new sand or live rock. Last time sand and lr was added was Jan 2016.

 

[pokerdobe]

Did you accidentally put some salt into your top off water? What else are you dosing?

 

 

My topoff is clean. I checked both my source and my reservoir - TDS is 0 and a separate dKH test reveals 0 alkalinity at both the source and topoff container.

 

I am not dosing anything at the moment.

 

The only other thing going into my tank is frozen foods and Red Sea Energy A+B.

[dandelion]

That's very strange. Has there been any change in flow? Maybe the water is now blowing at your rocks that have non-dissolved supplement, getting it into solution? What about pH?

 

 

 

My topoff is clean. I checked both my source and my reservoir - TDS is 0 and a separate dKH test reveals 0 alkalinity at both the source and topoff container.

I am not dosing anything at the moment.

 

The only other thing going into my tank is frozen foods and Red Sea Energy A+B.

[pokerdobe]

Your guess is as good as mine. No change in flow.

pH is 8.1

 

That's very strange. Has there been any change in flow? Maybe the water is now blowing at your rocks that have non-dissolved supplement, getting it into solution? What about pH?

 

 

[dandelion]

Have you been tracking your pH as well? Has it been going higher? Have you been opening the windows or improving ventilation at home or some family member going out of town? Changes in your light cycle? Refugium? Maybe it is a lower dissolved carbon dioxide that pushed the equilibrium from carbonic acid to a higher concentration of carbonate and bicarbonate ions, which make up like 96% of alkalinity.

 

 

Your guess is as good as mine. No change in flow.

pH is 8.1

 

[Clown79]

What is your calcium and mag at?

[pokerdobe]

What is your calcium and mag at?

Ca - 480

Mg - 1440

[pokerdobe]

I don't actively track my pH - I'll log the pH over the next week and see how it is going.

 

No changes in light cycle and I do not have a fuge.

 

Have you been tracking your pH as well? Has it been going higher? Have you been opening the windows or improving ventilation at home or some family member going out of town? Changes in your light cycle? Refugium? Maybe it is a lower dissolved carbon dioxide that pushed the equilibrium from carbonic acid to a higher concentration of carbonate and bicarbonate ions, which make up like 96% of alkalinity.

 

 

[dandelion]

Technically pH shouldn't change alkalinity that much though.... it usually is the other way round. It's possible though pH changed causes more dissolution of your rocks, hence the increase in alkalinity. But still that doesn't explain the change of almost 1 dKH.

 

I don't actively track my pH - I'll log the pH over the next week and see how it is going.

 

No changes in light cycle and I do not have a fuge.

 

[Mariaface]

I first thought of all the questions above

 

But what test kit are you using, and how frequently did you test?

[pokerdobe]

Test kits below:

 

Alk - Red Sea

Ca - Salifert

Mg - Elos

Nitrate - Salifert

Po4 - Red Sea

Ph - Red Sea

S.g - Milwaukee

 

On average, I probably test about once a week. More so recently due to the issues.

 

 

I first thought of all the questions above

 

But what test kit are you using, and how frequently did you test?

[gonebad395]

What salt are you using? If it's Red Sea I've heard of alk buildimg up even with water changes be cause they test with a higher alk then most salts just some food for thought trying to help. Just something I read figured it couldn't hurt

[pokerdobe]

I did recently switch salts about a month or so ago. I was using Aquaforest until their last batch tested alk in the 11's - I've been using Fritz.

 

 

What salt are you using? If it's Red Sea I've heard of alk buildimg up even with water changes be cause they test with a higher alk then most salts just some food for thought trying to help. Just something I read figured it couldn't hurt

[gonebad395]

When did you switch maybe it could be that idk just brain storming for you

[Mariaface]

But when you kept track of alk throughout the week, how frequently did you test it?

 

Red Sea's test kits are notorious for tripping people up with the 'end' color; there's an instructional video floating around from RS themselves explaining the titration point is the second the color changes after a shake, and the measurement is the drop before that. I have no reason to doubt that you're consistent in what you consider your end point, but sometimes there's a three drop discrepancy between when the liquid changes colors during the shaking, but does't remain changed after swirling the tube, and it gets iffy.

 

If you tested more than a couple/few times (say, daily or even twice a day), and saw alk consistently rising, I wouldn't be taking that titration point into consideration.

 

Otherwise, if the difference is there and less than 1dKH over a week:

-Any salt creep capable of falling back into the water?

-How large is the tank in total water volume?

-Maybe you did a water change and tested alk at 10.1, but you actually added a bit more water than you took out? That extra water can evaporate and raise parameters (did you track salinity, cal, and mag throughout the week?), though it'd take significantly more water the larger the tank is...

-Maybe it tested at 10.1 when added, but hadn't completely mixed (not sure what your water change routine is) or salinity was tested at a lower temperature?

 

 

On the topic of bleached tips and STN: Make sure your nutrients are high enough to be in balance with alk as high as this. What are you getting for phosphate and nitrate? Low nutrients and high alk can cause 'alk burn' where you see these symptoms. High nutrients and low alk can cause browning, and high enough phosphate will inhibit calcification, too.

[pokerdobe]

I usually test 2x during an alk test and I average the results if the discrepancy isn't large. I actually did not know about the end point being the drop before the color change. I'll retest with this in mind, as well as the other factors you stated about red sea testing. My usual kit is salifert, but I am using red sea because my lfs is out of salifert.

 

To your other questions:

 

Total tank volume is approximately 55-60 gallons, depending on how much water live rock is displacing. For reference, my tank is the Red Sea Reefer 250.

 

I'll check into the water volume in vs water volume out. When I do a water change, I usually fill up 2 home depot orange 5 gallon buckets and replace with separate 5 gallon home depot water buckets.

 

Water change practice for me is to mix the salt the night before. Sometimes I will get lazy and mix it a couple days before hand.

 

Unsure of the salt creep.

 

My other parameters as follows, accurate as of yesterday.

 

No3 - 2.5ppm (salifert)

Po4 - ,04ppm (red sea)

Ca - 490ppm (salifert)

Mg - 1440ppm (elos)

S.g - 1.026 (Milwaukee MA887)

 

But when you kept track of alk throughout the week, how frequently did you test it?

 

Red Sea's test kits are notorious for tripping people up with the 'end' color; there's an instructional video floating around from RS themselves explaining the titration point is the second the color changes after a shake, and the measurement is the drop before that. I have no reason to doubt that you're consistent in what you consider your end point, but sometimes there's a three drop discrepancy between when the liquid changes colors during the shaking, but does't remain changed after swirling the tube, and it gets iffy.

 

If you tested more than a couple/few times (say, daily or even twice a day), and saw alk consistently rising, I wouldn't be taking that titration point into consideration.

 

Otherwise, if the difference is there and less than 1dKH over a week:

-Any salt creep capable of falling back into the water?

-How large is the tank in total water volume?

-Maybe you did a water change and tested alk at 10.1, but you actually added a bit more water than you took out? That extra water can evaporate and raise parameters (did you track salinity, cal, and mag throughout the week?), though it'd take significantly more water the larger the tank is...

-Maybe it tested at 10.1 when added, but hadn't completely mixed (not sure what your water change routine is) or salinity was tested at a lower temperature?

 

 

On the topic of bleached tips and STN: Make sure your nutrients are high enough to be in balance with alk as high as this. What are you getting for phosphate and nitrate? Low nutrients and high alk can cause 'alk burn' where you see these symptoms. High nutrients and low alk can cause browning, and high enough phosphate will inhibit calcification, too.

[Mariaface]

So it looks like both alk and calcium have gone up, .7dKH alk and 10ppm calcium? Magnesium might be/look the same, but I don't know the increments for the Elos mag test or how accurate it'll be from test to test.

 

This article shows that that's similar to a balanced ratio (usually added via two part at around 10ppm cal per .5dKH alk, but maybe evap or salt creep is an element), and that sometimes alkalinity will go up if an element of it is biologically metabolized (like calcium acetate is metabolized and frees up hydroxide to raise alk).

 

As for nutrients: A lot of tanks keeping phophates in the .03-.05 range and nitrates between 1 and 5 are actually running lower alk to deal with those low nutrient levels. Markalot, for example, is running that gorgeous tank at around 6.7-7.7 dKH depending on how his dosing is keeping up. Going higher will get you faster growth, but only if you keep up with feeding to provide organic nutrients for the corals.