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lrhorer
08/05/2017, 08:22 PM
I posted this (http://www.reefcentral.com/forums/showthread.php?p=25159196#post25159196) thread about a situation I encountered a few months ago. Once I got the carbonate and borate levels into a reasonable balance by dosing NsOH, the pH went back up into a much more tolerable range for the critters. Since then, the pH has been very slowly but steadily rising. Most days it would peak above 4.3, and I would add a little CO2 to bring the pH down a little. Hardness is steady at 10, and salinity at 1.24. Ammonia is a bare trace (below 0.25), and Nitrate and Nitrate at or near 0. I can't measure phosphates at the moment, because the reference sheet has disappeared, but prior to it going missing, the Phosphates were zero. Algae is pretty well in check, especially Filamentous Algae and Cyanobacteria. I keep a few small balls of Chato in the tank and it is growing, but not growing wild. It has been a week since the last water change of 5g (100g tank).

Yesterday, I noticed my little Engineer Goby seemed to be breathing hard and seeking the surface. Today the Goby is clearly dying, and the mushroom has bleached overnight. One of the Featherduster worms has shed its crown an is lying half exposed out of its sheath. I have three small colonies of button polyps that have suddenly begun to migrate off their bases, and the Sea Apple, who has been happily ensconced right underneath a flow pump with its tentacles stretched up into the stream for many weeks is now moving about the tank, although it does not look particularly stressed. The rest of the inverts and fish don't seem too badly affected.

The pH was 5.21.

I added a healthy dose of CO2 to bring it down to 8.45. The Goby and the aforementioned inverts remained severely stressed.

So what now?

scuzy
08/05/2017, 08:27 PM
Co2 lowers your pH why are you lowering pH when it should be going up?

karimwassef
08/05/2017, 08:29 PM
I think you mean 8.43 and 8.52? Your numbers above don't make sense

bertoni
08/05/2017, 08:57 PM
I agree that those numbers don't make sense.

lrhorer
08/06/2017, 04:22 PM
'Sorry. That was a typo, and I don't have permissions to edit my posts.. The pH was 8.52. I dosed with CO2 to get it to 8.45. I didn't go any further than that, because shock could potentially cause as much damage as high pH. Through the night the pH dropped to something below 8.3. Right now it is 8.31. Why the pH rose eventually to 8.52 I have no idea.

I have added nothing to the water the last few weeks other than RO water with a hardness of 1 to maintain the water level and SG, occasional small doses of CO2 in water with a hardness of 11 to keep the pH under 8.4, and 5g water changes every week with artificial seawater at SG 1.24 and hardness of 11.

All the livestock seemed very healthy with good appetites, including the goby the worm, and the corals, until the day before yesterday. The worm, which was hanging limply out of its tube, has withdrawn itself. I do not know if it is alive or dead. The corals seem in better shape. Their tentacles are well extended. I do not know about the Goby. I don't see a corpse, but he could well be dead in one of them many hiding places in the tank. He mostly keeps company with three other Gobies - two Bar Gobies and a Watchman - under an old piece of coral. The rest of the fish are all more mobile today, and the Sea Apple has returned to his old spot below the pump. And yes, I am keeping a very close eye on him. I know what the members of his genus can do. Indeed, it was the first thing I considered.

karimwassef
08/06/2017, 04:48 PM
pH rises due to photosynthesis that consumes CO2. It can also rise as fresh atmospheric air (lower concentration of CO2) is added or injected.

My advice is to stop watching pH. Measure your Alkalinity, then Calcium, then Magnesium.

Alkalinity is THE critical variable imo for a reef tank. pH is a measure of aeration imo. If you're getting fresh air and injecting it into the skimmer, that's really it.

Sk8r
08/06/2017, 04:59 PM
^ This. Forget ph, generally. Get your alk to 8.3 and your mg to 1350.

lrhorer
08/06/2017, 10:15 PM
pH rises due to photosynthesis that consumes CO2. It can also rise as fresh atmospheric air (lower concentration of CO2) is added or injected.
It also rises with the increasing presence of any basic ionic chemical or the depletion of any acidic ionic chemical and goes down with the increase of any acidic chemical or the depletion of any basic chemical.

As an example, Alcohols are generally miscible covalent molecules, and as such have no primary effect on pH. In the presence of Alcohols, however, certain bacteria and some yeasts will break the alcohol down into a Carboxylic acid (such as Acetic acid) and some hydroxyl or methyl group, depending on the specific Alcohol. The result will be a decrease in pH.

Some macro-Algae store significant amounts of strong acids - even sulfuric acid - in their tissues. The decay of such plants can cause the pH to drop precipitously. On the other side of the equation, some plants store large amounts of strong bases in their tissues. They have the ability to raise the pH a great deal if they release these into the environment.

Many creatures (including corals, sponges, snails, marine worms and jellyfish) store rather large amounts of formic acid in their tissues. Upon release, this will also raise the pH.

My advice is to stop watching pH.
Had I done that in a strict sense, I would have lost quite a bit of livestock, possibly even all of it.

Measure your Alkalinity
Stable at 10, before during and after this second event. During the prior event, with a precipitous fall of pH which stressed literally everything in the tank and killed off a fair amount, the hardness was above 12.

then Calcium, then Magnesium.
I'll get some additional kits tomorrow, and replace my reef master reference, but in the meantime, please explain exactly what process could have caused either Ca or Mg to deviate precipitously in less than 12 hours to the point livestock was dying, and then was restored again in less than 12 hours with nothing but the addition of CO2.

Alkalinity is THE critical variable imo for a reef tank.
That has been said before with no authority. Despite claims to the contrary, my tank suffered a fatal drop in pH causing widespready morbidity and significant mortality in an environment with a dKH greater than 12. Now it has experienced an additional precipitous increase in pH with no change in Carbonate hardness.

(Again not meaning to be overly pedantic, but the "alkalinity" of any aqueous solution in equilibrium is PRECISELY equal to the KSP of water minus the acidity of the aqueous solution. More rigorously, the alkalinity of any stable aqueous solution is given by:

pH + pOH = 14

where ph is -10log of the molar concentration of H+ ions - acidity - and pOH - alkalinity - is -10Log of the molar concentration of OH- ions. In neutral water, regardless of what acids or bases are present, the number of H+ ions (typically H3O+) is equal to the number of OH- ions, each of which is specifically 5.012 moles/liter.)

pH is a measure of aeration imo.
No, pH is a measure of the concentration of H+ ions in aqueous solution, period, and it is not in any way a matter of opinion. If pure H2O is infused with a large amount of normal room air, the pH will ordinarily rise, because ordinary room air has more O2 than CO2. The water I used to dose the tank the last few weeks always dropped the pH, because it is saturated at 5 or 6 atmospheres of pure CO2.

Note during these episodes, the aeration of the tank never changed at all. The main source of room aeration is the skimmer, which has been operating normally at the same throughput for months. The secondary source is the wet-dry filter, whose throughput has also not changed significantly.

If you're getting fresh air and injecting it into the skimmer, that's really it.

If that is "it", then what caused the pH to drop suddenly down to 7.5 and then many weeks later to spike suddenly at 8.5? If the pH was not causative in the morbidity and mortality that very clearly followed precisely the peaks of this metric, then what was? It is true a valid correlation does not necessarily establish cause and effect, but with the Carbonate hardness, Specific Gravity, temperature and toxic contaminants being constant and well within optimal levels, what else do you propose might suddenly accompany the observations in less than a 12 hour cycle with only the addition of NaOH in the first (low pH) event, and only the addition of CO2 in the second (high pH) event.

lrhorer
08/06/2017, 10:28 PM
Note: one minor correction. During the first even, I did add an air stone to the sump in an attempt to increase the pH. It was removed when it had no discernible effect.

dartier
08/06/2017, 10:46 PM
Ditto with the advice already given. For the most part, I ignore PH. In my last house, When I noticed it was low, I plumbed in outside air for the skimmer. That helped a bit. Then I installed a whole house HRV to get fresher air into the house. That helped *a lot*.

The is pretty much the extent of it. Oh, and in my new house, I installed an HRV right away.

Dennis

karimwassef
08/07/2017, 06:46 AM
Unless your tank is so different from every other reef tank, the advice to stop measuring pH is good. Unless you had an entire filtration system (or life) fail and die all at once, the release of acids or bases to impact pH to the degree discussed doesn't happen in reef tanks.

You state absolute definitions but ignore the fact that in reef tanks, the scenarios you are positioning don't happen because the total cumulative source of these acids and bases are negligible or sequestered, not released. So when we say CO2 is the dominant controller of pH, that's because the impact of other elements is minimal in a reef. This assumes that you have a reef made of salt water using RODI and a known synthetic salt to natural sea water salinity. If you choose to make yours with other elements, or accidentally drop a bucket of muriatic acid or borax into it, then the assumptions fail to hold and you're not running a normal reef tank.

Alkalinity's importance is not an opinion. It's the result of many chemists, and hobbyists through years of personal experience and remarkable success who have given example after example of its impact. Personally, I've found that keeping alkalinity stable will keep everything else in balance (in my tank). I've even experimented with salinity, letting it drop to 1.018, and corals lived as long as Alk was good. I've raised and lowered the temp from 68 to 84 ... no deaths. But wiggle Alkalinity just a bit over a short period of time and I had massive death.

When your Alk hit 12, up from 10 in 12 hours without external input, that should have alerted you that something was very wrong. Alkalinity is constantly being depleted in a normal reef tank unless you're actively adding it back in. That should have been a call to action to bring your Alk down slowly.

As far as precipitation, I used to suffer from that until I realized the incredible power of Mg. Mg basically interferes with abiotic precipitation so that there's an abundance of Alk and Ca without making a snowstorm of chalk. I keep Mg over 1600 and never had another snowstorm. Even with Ca ~ 600 and Alk ~ 8.5.

Look - everyone who replies to you is actually trying to help. I sense your frustration and I've been there too. There are times when it seems that something is happening in your tank that isn't like anyone else's- and maybe it is. But the truth is that it's a rare event that defies all precedence without wiping out a tank. Not impossible, but rare.

So if you believe that your tank's chemistry is departed from all others, let's look at that. Did you have a massive die off in a biological filter? Did you have deep sand beds that got disturbed?

Just trying to help :)

bertoni
08/07/2017, 01:51 PM
As I stated in your other thread, your tank probably underwent a precipitation event, which can cause a number of problems, including a massive drop in alkalinity.

pH at 8.5 is perfectly safe. I personally would ignore it. People have overdosed various supplements into tanks and run the pH higher than that without any effects on the animals.

If the alkalinity of the tank is in the 7-11 dKH range, then a pH of 8.5 probably indicates either that a high-pH alkalinity supplement has been added, or that photosynthesis is driving the pH up. Of course, making sure that the testing equipment is accurate. I've forgotten where we stand on that.

If 8.5 is too high for your safety zone, I would use a lower-pH alkalinity supplement, as appropriate, or try adding more aeration to the system. It's possible in theory that the air around the tank is becoming depleted in carbon dioxide, but I'm not sure how realistic that is. People have reported tanks that have enough photosynthesis that they needed to dose carbon dioxide. Your tank might be getting into that zone. In that case, a pH monitor or two controlling carbon dioxide might be safe enough to solve the problem.

karimwassef
08/07/2017, 02:27 PM
If the tank has an oversized scrubber or is housed in a greenhouse with lots of plants, it could deplete CO2 during light hours.

lrhorer
08/19/2017, 05:49 AM
Current metrics:

Temp - 77F
pH - 8.41 (8.52 before dosing with 500ml Co2 + H2O)
SG - 1.024
ppm/dKH - 143/8
PO4 - 0
NO3 - 10 ppm
NO2 - 0
NH3-NH4 - 0.1 ppm
Ca - 300 ppm
Mg - 1040 ppm

lrhorer
08/19/2017, 05:52 AM
Unless your tank is so different from every other reef tank, the advice to stop measuring pH is good. Unless you had an entire filtration system (or life) fail and die all at once, the release of acids or bases to impact pH to the degree discussed doesn't happen in reef tanks.
I have no doubt that has been your experience. It's quite obvious I made at least two significant mistakes which threw the tank's chemistry pretty far out of balance. It takes a fairly toxic tank to kill off Colt and Leather corals in a matter of hours, after all. (Actually, they didn't die completely. Just in the last few days they have re-sprouted tiny tentacles from the old trunks. They are a small fraction of the size they were, but it seems they are alive.) It is also a far from balanced thank where none of the fish are eating at all, or even coming out of hiding.

The daily pH variation with no intervention ranges from around 8.25 prior to the lights coming on to 8.55 before the lights go out. If I leave the pH above 8.45 for more than a couple of hours, several of the corals bleach, and it takes days of me keeping the pH below 8.45 with fairly steady dosing of CO2 for them to recover. The Zoanthids have all apparently died, although they were quite happy before the pH began peaking above 5.0 every day.

Take a look at the enclosed photo. That is simply *NOT* a happy coral, but it has looked worse, and all I have to do to get it to heal is to keep after the pH, keeping it below 8.45 for several days in a row for it to recover. To do so, I do nothing but add CO2. I could to try lowering the dKH, but I am somewhat hesitant to do so, as the rising pH has been accompanied by a falling dKH. If someone can explain to me what is causing this counter-intuitive response, then I will be much more willing to try something.

So when we say CO2 is the dominant controller of pH, that's because the impact of other elements is minimal in a reef. This assumes that you have a reef made of salt water using RODI and a known synthetic salt to natural sea water salinity.
Precisely. It ASSUMES that which I clearly stated WAS NOT THE CASE.

If you choose to make yours with other elements, or accidentally drop a bucket of muriatic acid or borax into it, then the assumptions fail to hold and you're not running a normal reef tank.
That is correct. I specifically stated at the outset and several times along the way this was not an aquarium whose chemistry was in normal balance. Any conclusions or deductions based on said assumption are therefore suspect and not unlikely to be incorrect. Specifically, when the pH suddenly began dropping a little and I then over-dosed with 8.3 buffer, it dropped to 7.9 and would not budge. That's when the Colt and Leather corals started showing stress. Unwisely, I dosed with NaCO3. That's when the pH dropped to 7.5, and everything got sick except the crustaceans and the molluscs. No matter what else may be, it is definitely not an aquarium with a normal chemistry balance when almost everything in the tank is not eating, and a number of things are dying. At such a point, any suppositions derived from a normal tank may well not apply.

That is precisely why I originally posted the other thread. Going through this forum, I came across a number of posts that strongly suggested problems such as I had were in fact encountered by other members of this board, yet when they posted their issues, they met with much of the same blank assumptions, potentially incorrect diagnoses, and in at least some cases bad advice, not to mention derision and disdain, just as I did.

Let me hasten to say I am not suggesting you were ever derisive or disdainful. I don't recall ever seeing your name next to anything of the sort. Nonetheless, both other people and myself have been the target of just such posts.

Alkalinity's importance is not an opinion. It's the result of many chemists, and hobbyists through years of personal experience and remarkable success who have given example after example of its impact.
Actually, that still technically makes it an opinion. That doesn't mean it is wrong, just what it is. The simple truth here, however, is empirical data always trumps opinions, hypotheses, or even theories (and there is nothihing more certain than a theory). The fact is, my carbonate hardness was higher than any normal solution in equilibrium can ever be - not even remotely low - yet the pH was pegged at 7.5, and it was NOT due to high CO2 in the environment or in the tank.

Personally, I've found that keeping alkalinity stable will keep everything else in balance (in my tank). I've even experimented with salinity, letting it drop to 1.018, and corals lived as long as Alk was good. I've raised and lowered the temp from 68 to 84 ... no deaths. But wiggle Alkalinity just a bit over a short period of time and I had massive death.
I have no doubt whatsoever this is true. Indeed, I submit that very thing is why my overdosing the tank with borates and carbonates resulted in very little death. In fact, that is another data point supporting the statement the water hardness was never low. Inferentially, the dKH started out over 11, so it could not climb very much higher - and it didn't. Instead, the tank saturated with one set of ions (I suspect borates) and then with carbonates. This explains why the tank first buffered at pH 7.9 and then at 7.5, and why massive amounts of carbonates began to precipitate.

The advice I should have been given - and upon which I landed after I stopped an thought for a few minutes - was to add NaOH. That one thing slowly and more or less steadily alleviated the issue for several months. What the problem is now, I am not quite sure. The carbonate hardness has actually gone down a little in the last few weeks, but the pH is climbing.

When your Alk hit 12, up from 10 in 12 hours without external input
I never said that happened. To my knowledge, it never did. What I said was, 'When I got the kit, the harddness was above 12." After I stopped using the pre-mixed water from the LFS, whose hardness was 11, I got the dKH down to 10." It was still at 10, a few months later, when the pH began rising, and the Zoanthids, Protopalythoas, and Engineer Goby all got sick or died.

that should have alerted you that something was very wrong. Alkalinity is constantly being depleted in a normal reef tank unless you're actively adding it back in.
I am aware of that. It's why I added the 8.3 buffer. 'Not the best solution, I know now.

That should have been a call to action to bring your Alk down slowly.
It did not happen that way, but that is precisely what I did, by adding small amounts of NaOH on a regular schedule until the pH rose above 8.2 and stayed there. It was after that I finally received the Alk test kit, and at that point the dKH was 10.

As far as precipitation, I used to suffer from that until I realized the incredible power of Mg.
I never had it before, or since, but I do need to get my Mg up some. It's on;y at 1040.

Mg basically interferes with abiotic precipitation so that there's an abundance of Alk and Ca without making a snowstorm of chalk.
Well, it wasn't a snowstorm, and it wasn't chalk. Basically it is limestone, and I am still working to scrape some of it off the glass, where it deposited in a fairly thick, very hard layer.

I keep Mg over 1600 and never had another snowstorm. Even with Ca ~ 600 and Alk ~ 8.5.
Interesting. My Mg kit is from Red Sea, and the highest they suggest is 1390, and that only for accelerated growth of clams and SPS corals. For SPS corals in mature / low growth tanks, they recommend 1310.

Look - everyone who replies to you is actually trying to help.
Really? I fail to see how the following response could be considered helpful in any way:

"Yawn...... "

Even some of the posts that are not nearly as sarcastic still fail to be helpful. The statement, "Chasing PH is a fools errand!!!", isn't helpful. It says, in effect, "You are doing it wrong", without bothering to submit what would constitute "Doing it right", let alone explaining why.

For myself, I don't really care. I wasn't seeking advice when I posted the former thread. I was posting a narrative about a past event that demonstrated some similar or perhaps even identical events posted here were met with inappropriate responses, and show these folks were neither lunatic nor stupid. To that end, I rather rest my case.

I sense your frustration and I've been there too.
My main frustration is not that, by a wide margin. My frustrations are these:

1. People are either not reading what I wrote carefully enough, or else I am not writing clearly enough. Whichever is the case, it means little or nothing very useful in context is exposed as the thread continues.

2. People are making assumptions with no supporting assertions with a result identical to #1.

3. People are making invalid assumptions, inferences, and deductions.

There are times when it seems that something is happening in your tank that isn't like anyone else's

No, precisely the opposite. My experiences WRT these two I believe are precisely or nearly the same as others have experienced here, and they were given various advice with an air of certainty not ever justified when one is not on the scene themselves. They also wind up being belittled and bullied.

- and maybe it is. But the truth is that it's a rare event that defies all precedence without wiping out a tank. Not impossible, but rare.
I find myself a bit at a loss for comment. To a certain extent, if something is not unusual, tnen why talk about it? If someone were to post, "I have a perfectly ordinary tank with no unexpected issues", then what would one discuss with them? The weather?

Of course, some people do have very ordinary issues or questions, but those are certainly not the interesting cases.

So if you believe that your tank's chemistry is departed from all others, let's look at that.

Is, or was? Remember, there are two different events, here, complementary to each other. One is in the past: super high carbonate levels along with low pH and a serious impact to thee health of most of the tank. The other is right now: slowly falling hardness levels with rising pH, and an impact to critters that were not impacted by the other event.

Do they have a common root cause? Possibly. The main point here is both effects are contrary to the common wisdom embedded here.

Did you have a massive die off in a biological filter?
I don't think so, other than the algae. Had that happened, I would expect spikes in Ammonia or Nitrites. I would also expect there to be maladies evident in the fauna that were not so clearly and quickly mitigated by the addition of nothing other than NaOH or CO2.

Did you have deep sand beds that got disturbed?
No. My sand bed (Aragonite) is only 2", and I mostly let the clean-up crew keep it groomed. Every few weeks, I do run a vacuum through it, but I had not done so within 2 weeks of either event.

Just trying to help :)
Yes, you are. Thank you. Meanwhile I would like to point out asking questions is the right way to go about it. I learned many decades ago the right way to fix a problem is not to make pronouncements or to provide diagnoses. The best way is to keep asking questions until one asks all the right ones.

lrhorer
08/19/2017, 06:47 AM
As I stated in your other thread, your tank probably underwent a precipitation event
I stated that precise thing.

which can cause a number of problems, including a massive drop in alkalinity.
1. Only if the precipitation is caused by the common ion effect. That is not the case here. I was dosing with Carbonates, not Sodium or Calcium salts. It is not possible to cause a drop in dissolved Carbonates by adding Carbonates.

2. If that were the case, then my replacing more than 50% of the water with water that had a hardness of 11 would have significantly impacted the overall hardness, and thus the pH.

pH at 8.5 is perfectly safe. I personally would ignore it. People have overdosed various supplements into tanks and run the pH higher than that without any effects on the animals.
Then why are several of my corals clearly stressed whenever the pH remains above 8.45 for more than a couple of hours and recover when I diligently keep the pH below 8.45? Not just once, but several times. Those that did not die, of course.

If the alkalinity of the tank is in the 7-11 dKH range, then a pH of 8.5 probably indicates either that a high-pH alkalinity supplement has been added
Nope. First of all, the dKH is falling, not rising. As of last night it is at 8, down from 10 a couple of weeks ago. Secondly, I had added nothing to the tank but RO water to replace evaporation, food, and CO2 infused RO water to lower pH. It is requiring more and more to get the pH below 8.45 at the end of the day.

I did do a partial water change a few hours ago. We'll see how that plays out.

or that photosynthesis is driving the pH up.
Well, of course. Assuming there is a reasonable amount of flora in the tank, that will always be the case. Pre-dawn pH levels are around 8.23. They don't climb above 8.45 until around noon.

Of course, making sure that the testing equipment is accurate. I've forgotten where we stand on that.
The pH meter is properly calibrated via standard references. It also matches the much less accurate indicator solution test. I don't have any reference solution for dKH, but it measures 1 for both RO water and the water out of my faucet (which is softened), 11 for the pre-mixed sea water from the LFS, and 12 for the house water before it enters the softener.

If 8.5 is too high for your safety zone, I would use a lower-pH alkalinity supplement
At this time I am not using any at all. 'Not until I have a better handle on the current situation.

or try adding more aeration to the system.
I doubt it would help, but I will give it a try. It's easy enough.

It's possible in theory that the air around the tank is becoming depleted in carbon dioxide, but I'm not sure how realistic that is.
It's not "becoming" depleted. It just never had it. My house sits on a 1 acre lot, and only 2 human beings live in that acre, plus a number of small animals. The yard is filled with trees, grass, and various other plants. My neighbors all have similar living spaces, so the total fauna load is probably about 3 - 4 people per acre, with several tons of flora per acre. There is just not a lot of CO2 in the air, here. This was evidenced in the other post by the fact adding a CO2 scrubber has almost no effect on the pH of the tank.

People have reported tanks that have enough photosynthesis that they needed to dose carbon dioxide. Your tank might be getting into that zone.
Possibly. I did harvest most of the Chato a couple of days ago, but it didn't make much difference. Honestly, other than that and a small patch of filamentous algae on the spiny oyster, I don't really have all that much flora in the tank any more.

In that case, a pH monitor or two controlling carbon dioxide might be safe enough to solve the problem.
Mmm. Yeah, but I would then have to buy an electrically controlled CO2 dispenser. Cost aside, I would really rather employ a balanced biological approach. An obvious solution might be to increase the number and size of fish. Of course, your notion is I already have too many, and your point there is well considered. I could wind up in a situation where my filtration systems cannot host any more nitrobactre, and the ammonia starts rising, or even worse the system recycles.

outssider
08/19/2017, 05:53 PM
I've been reading this thread from the start....we've come up with every plausible explanation that could cause your problem....I think we're all stumped !!

I would however raise your mag up from 1050 to at least 1250 but I doubt that's your problem

lrhorer
08/19/2017, 07:05 PM
I've been reading this thread from the start....we've come up with every plausible explanation that could cause your problem....I think we're all stumped !!
Actually, I suspect you are not. There is a lot of accumulated knowledge here, and I strongly suspect that any number of you have the answers - note the plural - at your collective fingertips. I think all that may be required is a small paradigm shift.

No matter what, of course, I will continue to investigate this new issue until it is resolved. In the meantime, I just have to figure a way keep the CO2 up on a more continual basis.

I would however raise your mag up from 1050 to at least 1250 but I doubt that's your problem
I would think so, with one possible exception. Raising the Mg might help the affected corals cope better with the high pH. I suppose Sr could also be an issue. Reducing the number of stressors on an organism can often help it deal with one stressor. OTOH, I feel may be reaching far afield, here.

karimwassef
08/19/2017, 11:34 PM
If I were in your shoes:

I'd increase Mg to 1600.
I'd get an air CO2 monitor (~$100)
I'd get a second scientific pH probe
I'd get a second Alk test kit

I'd collect data: pH, CO2, salinity, temp, Mg, Ca, Alk every 3 hours for as many days as you can

The additional kits and probes are to validate your measurements.

This sounds extreme but when I was trying to understand what was happening in my tank, that's what I did...

Get data

outssider
08/20/2017, 05:36 PM
Is your cal still at 300 ?....if so, that's way low, I'd bring that up too !

topjimmy
08/21/2017, 08:56 AM
I would suggest that you quit messing with your tank and let it stabilize. Do some water changes with a commercially available salt mix. Don't add anything else for a while and see what happens.

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