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Offline dbowman

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alk adjustment
« on: August 24, 2020, 14:18:20 »
I had KH 12.5 decided to bring it down with WC's. over a month i have brought it down to 10. with a max change of 1dKH per WC. it has gone up 1 in a two week period. How fast can you drop the ALK without stressing livestock. what corals or other animals are the most sensitive to ALK changes?
thanks,
Dave

Offline dbjonesjr

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Re: alk adjustment
« Reply #1 on: August 24, 2020, 16:24:26 »
How is your alkalinity increasing???

Offline dbowman

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Re: alk adjustment
« Reply #2 on: August 24, 2020, 16:50:13 »
my suspicion is man made rock dissolving

Offline Heinbaughb

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Re: alk adjustment
« Reply #3 on: August 24, 2020, 17:07:46 »
What is the alk level of your salt mix? I’ve been holding a steady 14.0 for a couple months now without negative effects.

Offline dbjonesjr

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Re: alk adjustment
« Reply #4 on: August 24, 2020, 17:26:04 »
Assuming your pH is at normal levels that should be damn near impossible. You have some kind of alkalinity source leaching in or your salinity is rising.

Offline dbowman

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Re: alk adjustment
« Reply #5 on: August 24, 2020, 18:30:42 »
IO salt mixing at 8.6 dKH, 1.026 sp.gr.
tank was salt low in April with 6 dKH my refract was out of calibration and was reading high. i calibrated it with the standard and realized it was weak. raised salinity and dKH was 9 May 1. by the 20th it was 10. having added some Mg. June 8 it was 11. added Ca, July 12 it was 12.5
so probably not caused by dissolving concrete. what concerns me is that the synthetic 'rock' seems to have larger holes in it than i remember at the time i put them in. dust that is generated is chalky. I believe that the pH and hardness would not attack the rock like it seemed to in the FW tank that a friend had put it in without realizing that it might not be compatible. he pulled it out of his tank and gave it to me as i was setting up my SW tank.

Offline SweetReefOH

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Re: alk adjustment
« Reply #6 on: August 25, 2020, 07:29:17 »
Dave, in order to understand, we are “assuming” a lot of things as we read.

Are you using an auto top off to keep salinity stable?

Can you show us a picture of this concrete rock? Are you sure it’s material is reef safe??

Are you using calibration fluid to check your refractometer EVERY time you check salinity with it?

What kit are you using to test alk? Is it still good? Have you tested the kit with someone else’s system to be sure it’s accurate?

What all are you dosing into the tank, if anything?

Alkalinity will not increase on its own. It is always being consumed by organisms, calcerous algae, etc. So there has to be a contributing factor somewhere. Hopefully we can figure it out.

Offline dbjonesjr

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Re: alk adjustment
« Reply #7 on: August 25, 2020, 07:32:02 »
Second what SweetReefOH said. I had a problem a while back where my refractometer wasn’t getting calibrated every time I checked salinity and ended up near 40 ppm causing all other elements to test higher. Outside that and a coding method I’m not sure what could be causing alkalinity to raise.

Offline dbowman

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Re: alk adjustment
« Reply #8 on: August 25, 2020, 10:04:51 »
i am using ato
i am not sure the material is reef safe
i calibrated once and when i just checked it had drifted to 1.028
which means my salinity is actually 1.024 now WC's having been made with weak SW
checking with salifert. testing DT and SW drum. last test 10 and 8.6 respectively test could be bad exp. date 1/2025
 i am not dosing anything regularly i have added Mg and ESV B-Ionic two part a couple of times
 i have included pictures of a couple of rocks 1744 the darker one is still in my DT it shows holes through the top left that were not there in April 1747 is a rock that i removed it shows white areas that have receded rather than encrusted or algae'd over. this rock is in a quarantine set up after i removed it from the DT

Offline dbowman

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Re: alk adjustment
« Reply #9 on: August 25, 2020, 10:07:48 »
i appreciate your input and am embarrassed about not calibrating the refract. i have never had one that drifted once set. i will check going forward.

Offline SweetReefOH

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alk adjustment
« Reply #10 on: August 25, 2020, 11:41:37 »
i am using ato
i am not sure the material is reef safe
i calibrated once and when i just checked it had drifted to 1.028
which means my salinity is actually 1.024 now WC's having been made with weak SW
checking with salifert. testing DT and SW drum. last test 10 and 8.6 respectively test could be bad exp. date 1/2025
 i am not dosing anything regularly i have added Mg and ESV B-Ionic two part a couple of times
 i have included pictures of a couple of rocks 1744 the darker one is still in my DT it shows holes through the top left that were not there in April 1747 is a rock that i removed it shows white areas that have receded rather than encrusted or algae'd over. this rock is in a quarantine set up after i removed it from the DT
I know refractometers are rugged and can take a beating. However, the calibration of the refractometer is extremely delicate. Any bump, shake, etc will knock it out of calibration. At least that’s the case with mine. Therefore I check calibration every time. I also use an Apex, so I do not have to use the refractometer unless something isn’t reading right. So we know there was some salinity inconsistencies. That will effect your alk readings. I also do not know how often you test alk, but I test it every day at the same time and record it in a spread sheet. I also mix new SW to 1.026, measured with the refractometer and then I test the alk of the new saltwater. This eliminates any possibility of an alk swing to my system.

If I were you, I would get my salinity to 1.025 or 1.026 and then make sure it’s staying there with your calibrated refractometer, daily. And then test alk and record it, every day, at the same time to see what it’s doing. Don’t make any other changes to the system until we get some consistent knowledge of what your alk is doing after getting salinity stable.

Seeing “new” holes show up in a rock is HIGHLY suspicious and suspect. But I wouldn’t do anything at this moment until we see what the alk numbers do.

The other issue is the potential of calcium carbonate rock to dissolve under low pH OR low magnesium. It’s highly possible and could explain new holes in live rock. Do you have a pH meter? I also noticed your Mg test was in the 900’s previously. If your salinity was off then that Mg number could be suspect as well.

Offline dbowman

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Re: alk adjustment
« Reply #11 on: August 25, 2020, 12:18:43 »
thanks sir. you make good points and i will use them. pH is 7.8 to 8 using Hanna pen.
 thanks again, adjusting course and steady on the beam, making revolutions for half ahead.

Offline SweetReefOH

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Re: alk adjustment
« Reply #12 on: August 25, 2020, 18:06:35 »
No problem. Track some numbers and let us know in a few days

 

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