PH Alk help

saltykid85

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Hello everyone.

I have a 60 cube mixed reef, with some sps, lps and soft stuff. I use reef crystals, and for some reason have trouble keeping alk and ph levels.

When I do a water change, my pinpoint meter will read 8.1 or so ph for a day or so, then after a few days, will dip down to 7.7-7.8, around 5oclock, when lights are still on. I measure alkalinity, and its around 7, even after a water change.

The lfs I go to uses red sea coral pro, and says its keep his alk around 11. Is reef crystals known for alk around 7, and do you think this is why my ph is low?

I have roughly 30x overturn an hour, protein skimmer, so I don't think co2 is the issue.

I have seachem ph buffer called 8.3 on hand, as well as kent alk buffer, but I am not sure if this is a bandaid or not. When I have used it before, the ph would rise, but fall after some time, less than a day.

Also when you dose in say your top off water, I put roughly 1 gallon a day in manually, (RO water). Do I put enough in the 1 gallon, for just one gallon, or do I add enough to treat the entire 60 gallons?

Very confused. I do not want to chase magical numbers, just don't understand why its low to begin with.
 

Boomer

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People are very misled by Alk. You can have a low Alk or a high Alk, both at the same pH. 99 % of all known pH issues in water are from CO2. So, just because one salt mix has a higher Alk over another does not me higher pH. You can actually have a higher pH with a lower Alk than one with a higher Alk. Why ? CO2.

Normally, RC and RS-Pro have a high Alk of around 11 - 12 dKH. It may just be you got a bad bag/ bucket.

Other things to look at

1. Salt settling in bag/bucket can create issues with salt mixes due to settling of the salt components based on their density and particle size. So, one should tumble the bag / bucket before you use it.

2. Adding the salt mix to fast to the water. Not all salts can be added to the water at the same rate. This is due the concentration of the salt ions and how much water is locked up in a salt mix component. This can cause precip in the mixing container, giving you a low Alk. So, you need to mix up the salt solutions slower. Meaning, adding less salt at time till you get to the Salinity you want.

3. Adding water to salt is the worst thing you can do. You always add salt to water, not the other way around.

Your pH went up then dropped, as when you do a WC you are removing CO2 from the water. Thus, the pH goes up and it will take a couple of days or so before the tank water picks up CO2 from the room air again. Same for the addition of CO2 from animals and plants. Poorly maintained tanks can have low room air CO2 and low pH, as the CO2 is accumulating at a faster rate than it can leave, brought about by decaying matter.

You need to test your salt solution mix Alk after a fresh batch is made BEFORE you add it to the tank. RC should come out around the same as RS-Pro.

In regards to SeaChem buffer. If it says SeaChem "Marine Buffer" on the bottle DO NOT use it in a reef tank. It is really only for FOT and will raise hell when you try to keep Alk and Calcium levels correctly. It also has to much Borate in it.

Based on your parameters your pH with no CO2 would be ~ 8.2. One would expect in most tanks like yours to be more like ~ pH 8 during the day and maybe 7.8 at night.

What time of the day are you taking theses pH readings ? You need to take one in the morning, before lights on and one in the late afternoon before lights out.
 

saltykid85

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Thank you for the thorough response. I had a reef tank from say 96, til 2008, the then fish only tank from 2000 til now, and now I also have reef tank. Truth is, I was a teen when I started, without internet, and didn't monitor these things. Now I do, and feel like I am relearning it all over again.

Couple of answers from my standpoint. My ph monitor, is on all the time, and prior to lights coming on , say 9 am, it always read 7.8, and as the day progressed, raised to a 8.1. Now after this water change, it was an 8.1, but has fell in last two days to 7.8 again.

I took the pinpoint monitor out to calibrate, I bought it new about a month ago, and that was the last I calibrated it. I used 7.0 and 10.0 solutions, and truth is, it was very inconsistent. I would go 7, to ten, back down to the 7 batch, and it would read 7.05 instead of 7.0. I then said it is what it is,and placed it back on tank. It then read on tank, 7.4 with lights out. So I am starting to lean towards it not working correctly.

I also, just did an alk test with api kit, and it read 9.5. I then checked my fowlr tank, and it was 10.5, and all along checking it, was always 6-7. So either I was using it incorrectly, miscounting drops, which I doubt, or perhaps the kit is now bad.

So it looks like today, my measurements are different, almost too much different to make me thing my brain has diminished or my testing devices are faulty.

I just cant blame myself or brain yet, because I certainly counted 10 drops to vial before it turned yellow.

Also, I never add water to salt. Typically, I have 2 25 gallon pvc vats I use. I fill with ro, which usually take a day to make, and then heat and circulate a day. I then dump entire bag, 50 gallons worth, of RC or IO, depending on which tank im changing, and let it mix for another 24 hours or so. So I can certainly add the bag in increments from now on.
 

saltykid85

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Just checked my ph again in reef tank, and lights have been off for two hours. My ph read a 7.48!! I have never seen it this low, I am recalibrating the thing now, my hope this new monitor is shot, but if now, what should I do. I already have 600 gph return pump in 60 gallon tank, and an mp 10?
 

Dan_P

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Thank you for the thorough response. I had a reef tank from say 96, til 2008, the then fish only tank from 2000 til now, and now I also have reef tank. Truth is, I was a teen when I started, without internet, and didn't monitor these things. Now I do, and feel like I am relearning it all over again.

Couple of answers from my standpoint. My ph monitor, is on all the time, and prior to lights coming on , say 9 am, it always read 7.8, and as the day progressed, raised to a 8.1. Now after this water change, it was an 8.1, but has fell in last two days to 7.8 again.

I took the pinpoint monitor out to calibrate, I bought it new about a month ago, and that was the last I calibrated it. I used 7.0 and 10.0 solutions, and truth is, it was very inconsistent. I would go 7, to ten, back down to the 7 batch, and it would read 7.05 instead of 7.0. I then said it is what it is,and placed it back on tank. It then read on tank, 7.4 with lights out. So I am starting to lean towards it not working correctly.

I also, just did an alk test with api kit, and it read 9.5. I then checked my fowlr tank, and it was 10.5, and all along checking it, was always 6-7. So either I was using it incorrectly, miscounting drops, which I doubt, or perhaps the kit is now bad.

So it looks like today, my measurements are different, almost too much different to make me thing my brain has diminished or my testing devices are faulty.

I just cant blame myself or brain yet, because I certainly counted 10 drops to vial before it turned yellow.

Also, I never add water to salt. Typically, I have 2 25 gallon pvc vats I use. I fill with ro, which usually take a day to make, and then heat and circulate a day. I then dump entire bag, 50 gallons worth, of RC or IO, depending on which tank im changing, and let it mix for another 24 hours or so. So I can certainly add the bag in increments from now on.
Here are a other things to consider while sorting out your issues.

pH meter calibration. The probe needs frequent calibration if you want accurate readings. I find my Pinpoint pH readings drifting several hundreds of a pH unit within days of calibration. The pH 7 buffer deteriorates faster than the pH 10 buffer. Best to use it once, but if you store it in a tightly capped bottle, it could be off in a week or two. When calibrating the probe, it takes time for the reading to settle. I allow a couple minutes in the buffer before adjusting the Pinpoint meter. I also rinse off the probe by swishing it in distilled water before changing buffers to minimize mixing one buffer with another. It is a fine point but helps preserve the buffer integrity. Calibration may take several buffer readings: 7, adjust, rinse, 10, adjust, rinse, 7, adjust, rinse, 10, adjust, rinse, 7, adjust, rinse p, 10.

pH probes can become fouled and need to be cleaned occassionally.

Is there electrical interference between lights and meter. Watch the pH reading with lights off and then turn lights on to see if there is a change in reading.

The difference in alkalinity between 6-7 and 10 seems too great to be explained by miscounting drops. Consider buying a new kit. Salifert seems both accurate and consistant.

There is a small pH dependency on alkalinity, maybe worth a 0.1-0.2 pH units per milliequivalent of alkalinity but I would consider Boomer's advice and suggestions on tracking down CO2 sources once you have convinced yourself that your measurements are reasonably accurate.

I would be interested in hearing how you resolve your issue.
 

d5332

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Please take the following with a grain of salt.....

Those stand alone PH meters sometimes require way too much calibration and hence you think you have a PH issue.

You do not need a PH of 8.3, do yourself a favor and dont chase it. PH in a range of 7.7 and 8.2 is fine and most likely will always be btw 7.8 and 8.0, JUST LET IT BE.

If you dont get cute with supplements, additives or exotic foods and remedies dont worry about PH. If you don't have a Calcium, Sulfur or other type of reactor that requires monitoring then don't worry about PH.

As for Alk, make sure you are testing properly, using the test kit correctly and if your tank is consuming Alk spend a week or two figuring out how much alk per day your tank needs and start adding it in by which ever means is best for you such as manually, daily, weekly, dose pump, etc, etc, etc
 

Boomer

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Slaty

Any time one gets odd pH very low or very high it is usually an users error, dirty probe, mis-calibrated probe, etc.. One should always have a good pH test kit sitting around to compare. As Dan pointed out look for electrical issues, to include is it operating on house power or batteries. There have been many issues with some meter to include this one on the meter power source.
 

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