Neptune Aquatics

Analog vs Digital and Age as a Factor

Dorfman

Dorfman

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Until recently I had been utilizing Red Sea liquid test kits to gauge water parameters which I inherited from the guy who gave me my first salt water tank almost 15 years ago. I don't know if it was the age of the test kits or the inaccuracy of liquid (analog) vs. digital (Hanna) test kits but I recently purchased digital testers for pH and alkalinity and found the results to vary drastically between the two. I have now begun attempting to correct my water parameters to the new digital reading and am experiencing some issues I need help with.

Basically, both my pH and alkalinity numbers were much lower (digital) than my liquid/analog test kits led me to believe. I have begun adding sodium bicarbonate to increase alkalinity and Reef Chem pH increaser (8.3) to increase the pH. After a few doses of each my pH is only at 7.75 but my alkalinity is at 12 as of this afternoon (mid-day lighting). Any suggestions as to how I can continue to bring up my pH without further increasing my alkalinity (I don't have a CO2 scrubber and didn't even know what they were good for until I began researching this issue earlier today). Collective wisdom required!
 
There's nothing drastically different with digital vs analog, both use the color changing value of a mixture and based on that color assigns a number to it. And alkalinity is by far the easiest test out there as it will (should) be a single reagent dripped into a sample of water and it changes color when the concentration gets high enough to match the alkalinity value, the color change with the Red Sea kit is fairly obvious too

That said, you're not going to be able to fight again the pH the tank wants to be at unless there are continuous changes happening to it. Now unfortunately people exhaling CO2 is one of those continuous changes, so to fight that a CO2 scrubber would be a continuous response. Another thing you can do is dose kalkwasser as your primary method of keeping alkalinity and calcium up, as kalkwasser as a high pH but even that your pH is going to end up equalizing over time, but if you don't have corals sucking up the calcium and alkalinity then that won't work either.

I know you mentioned watching BRS videos, and while yeah higher ph leads to more coral growth I would not stress out about it too much.
 
sfsuphysics said:
There's nothing drastically different with digital vs analog, both use the color changing value of a mixture and based on that color assigns a number to it. And alkalinity is by far the easiest test out there as it will (should) be a single reagent dripped into a sample of water and it changes color when the concentration gets high enough to match the alkalinity value, the color change with the Red Sea kit is fairly obvious too

That said, you're not going to be able to fight again the pH the tank wants to be at unless there are continuous changes happening to it. Now unfortunately people exhaling CO2 is one of those continuous changes, so to fight that a CO2 scrubber would be a continuous response. Another thing you can do is dose kalkwasser as your primary method of keeping alkalinity and calcium up, as kalkwasser as a high pH but even that your pH is going to end up equalizing over time, but if you don't have corals sucking up the calcium and alkalinity then that won't work either.

I know you mentioned watching BRS videos, and while yeah higher ph leads to more coral growth I would not stress out about it too much.
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I think the discrepancy in my results is most likely due to the reagents of the Red Sea kit are likely 15-20 yrs. old... (I know). But now that I have the digitial meters I have more specific numbers to track behavior by and to gauge how small changes I make are effecting water parameters. I have Kalk+ but have not used it yet as I don't have enough corals growing to consume the alk or Ca and those numbers are actually on the high end of good. The problem I'm trying to solve is how to raise pH from current 7.6 to 8.2ish without continuing to increase alk. I will try to kluge together a CO2 scrubber and see if that helps. Any other comments or suggestions welcome. Thanks for your help!
 
15-20 year old reagents? uh huh.... :)

As to your pH, I wouldn't worry too much about it, don't use Kalk unless you get corals that use calcium and alkainity and then use it to match that not the pH that you want. Do you have a relatively air tight house? maybe lots of people in the house? (or lots of pets). If you have the ability to pulling air from the outside for the skimmer basically has the same function as a CO2 scrubber while it doesn't "scrub" the CO2 out of the air, inside air has much MUCH higher concentrations of CO2 than the outside.
 
I'm not sure what "reef chem ph increaser" is, but it's likely raising your alkalinity too. So using that along with Sodium bicarbonate is likely boosting your alk twice.

Second to that, Sodium bicarbonate has a tendency to slightly LOWER PH, so you're working against yourself.

If your tank is doing well, I wouldn't have made such drastic adjustments based on one test kit.

I have also found the hanna alk test kit to be all over the place. At one point it was reading 1dkh lower than 3 other test methods, which were all reading very close to each other.

I agree ph is not a necessity. Alkalinity is much more important. Keep that in line, and then get a co2 scrubber if you want to optimize coral growth. If you don't have a ton of corals, don't worry about ph as long as it's between like 7.7 and 8.3

Also, those old test kits should be in the trash. Pick up some new kits.

Open a few windows near the tank (I know it's hard when it's cold) and that will likely help raise ph
 
sfsuphysics said:
15-20 year old reagents? uh huh.... :)

As to your pH, I wouldn't worry too much about it, don't use Kalk unless you get corals that use calcium and alkainity and then use it to match that not the pH that you want. Do you have a relatively air tight house? maybe lots of people in the house? (or lots of pets). If you have the ability to pulling air from the outside for the skimmer basically has the same function as a CO2 scrubber while it doesn't "scrub" the CO2 out of the air, inside air has much MUCH higher concentrations of CO2 than the outside.
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My sump and all filtration is done outside and water pumped into tank through pipes through wall so hoped air exchange would be sufficient. I can leave the window near tank open and see what effect that has.
 
Dorfman said:
My sump and all filtration is done outside and water pumped into tank through pipes through wall so hoped air exchange would be sufficient. I can leave the window near tank open and see what effect that has.
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Really? Wow. It's surprising you have such low ph then. I assume your skimmer is outside too?
 
Meshmez said:
Really? Wow. It's surprising you have such low ph then. I assume your skimmer is outside too?
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I’m assuming if the sump is outside it’s in some sort of enclosure. Is the enclosure sealed up pretty well or does it have some adequate air exchange? I can’t imagine your pH would be low if your sump is outside.

I would also be cautious with pH buffers. They’re typically sodium borate and will lead to an accumulation of it. Not many studies have been done on boron toxicity, but elevated levels can/will likely have undesirable effects.
 
RandyC said:
I’m assuming if the sump is outside it’s in some sort of enclosure. Is the enclosure sealed up pretty well or does it have some adequate air exchange? I can’t imagine your pH would be low if your sump is outside.

I would also be cautious with pH buffers. They’re typically sodium borate and will lead to an accumulation of it. Not many studies have been done on boron toxicity, but elevated levels can/will likely have undesirable effects.
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Yes all equipment is housed in a sort of plastic tool shed so its air-permeable. By "low" my pH is trending in the low to mid 7's which isnt terrible I just don't understand why I cannot get it into the low 8's. Thanks for the warning on the Boron buildup, will proceed with caution.
 
Dorfman said:
Yes all equipment is housed in a sort of plastic tool shed so its air-permeable. By "low" my pH is trending in the low to mid 7's which isnt terrible I just don't understand why I cannot get it into the low 8's. Thanks for the warning on the Boron buildup, will proceed with caution.
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Try running a hose from skimmer air intake to outside the shed. Or run it one night with the door open. If you can’t get it above 8, I’d suspect your testing tool or process.
 
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