Water tests... dKh Paranoia?

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TylerHaworth

Active Member
Well, I haven't ran any tests on my tank in about four months... So I decided to run a full battery today prior to doing my water change. All tests ran with my API test set.

pH - 8.4
Calcium - 500
dKh - 7
Nitrates - 0
Phosphates - 0

To me, the dKh seems to be a bit low while the ph and calcium are both at "ideal" levels... Am I paranoid, or should I begin look into supplementation?
 
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TylerHaworth

Active Member
No, I haven't checked Mg levels, don't have a test kit for it... Should probably do that...

I thought about KH supplementation, but wouldnt that push my pH up into an unacceptable range?
 
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BLAKEJOHN

Active Member
xspeedrj said:
Most buffers won't affect PH unless it is out of whack.
Click to expand...

Incorrect... most buffers will significantly impact your PH and are not recommended. Also the lower end of alk is 8dKH.

It usually seems that your alk will fall faster than your CA, although literature says otherwise.

I would knock out a couple of water changes if you dont do them regularly.

If you do do your water changes on a regular weekly schedule than you may need to look into supplementation. But before you do this have all your test kits in order, MG, CA, ALK, and understand how each element effects another.
 
Boomer

Boomer

Reef Sanctuary's Mr. Wizard
John

I do not know where you got that from but Alk most definitely drops faster than the Ca++ and for a number of reasons.



Tyler

Part of you low Alk may be due to the high pH and Ca++ you have. A high pH with high Ca++ likes to leave solution as precip of CaCO3 (Calcite, Aragonite). If 20 ppm Ca++ leaves solution it will take 2.8 dKH ppm with it which you nay not even notice. And if your Mg++ is low it is even worse.
 
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xspeedrj

Member
BlakeJohn:

I believe you are incorrect. "Buffer" by definition is specific to the PH and KH range for which it was designed. Like baking soda has a natural steady state of PH.
 
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BLAKEJOHN

Active Member
maybe I am wrong by the definition of "buffer", But even if you use baking soda to raise your dKH too much at once will still impact your PH by causing it to rise.

I didnt mean that raising your Dkh is not recomended but Items that are usually labeled as buffers are not usually recomended.
 
Boomer

Boomer

Reef Sanctuary's Mr. Wizard
The real issue it this you are not suppose to be using buffer to raise the pH but the Alk. Any buffer will raise the pH some and some more than others. The only time a buffer, such as soda ash (Sodium Carbonate, Baked Baking Soda) can be used to raise the pH if if both the pH and Alk are low. When you add a buffer like baking soda the pH actually drops and then rise hardly a tad if at all over the next 24 hrs. Soda Ash has a great impact on pH no matter what the Alk is. 99.9 % of all pH issues in seawater or even FW is not to little buffer buy high CO2. It makes no difference what the Alk is , 1 meq / l or 10 meq /, l if CO2 increase the pH will drop period. Buffers do about nothing for CO2. Any time you use a so called buffer to raise the pH and keep using that buffer to raise the pH or keep it a a certain pH two things happen. The CO2 can get even higher and the Alk always gets to higher. It is a myth to use buffers to raise the pH.

Like baking soda has a natural steady state of PH

A reef tank is nowhere near a steady state. A steady state means BS @ 1mol value will yield a pH of 8.3 @ stp, equilibrated with atm CO2. And when CO2 enters the equation that 8.3 means nothing
 
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TylerHaworth

Active Member
So, Boomer - Thanks for stopping in to my thread to help.

What would you recommend my first plan of action would be? Mg testing... And if it is low, Mg supplementation? Or something else?

I'm very wary (scared and ignorant) of jumping into the realm of additives, but understand it's a necessary evil that must be conquered eventually - I just want to do it the right way the first time, and before the problem gets way out of hand!
 
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BobBursek

Active Member
Yes get Mg in level, I think is 1280-1350, if Mg is low it is hard to get and keep Ca levels in there spot. Chasing PH is light chasing a woman that does not want a date. AS Boomer stated, if you need to dose Alk then you have your choice of BS or BBS. I have low PH so I went to a salt that has a lower Alk and then can dose BBS to raise the Alk and PH at the safe levels.
 
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xspeedrj

Member
Boomer:

I was not implying that the steady state of baking soda will be steady in a reef system. I understand its temporary effect when added to an aquarium, nor was I suggesting using a dKh buffer to affect PH. If you look at my reply I indicated that it should not affect PH in any significant way.
 
X

xspeedrj

Member
TylerHaworth:

Guess I should qualify all my statements. Nothing is absolute and water chemistry is a complex topic. I myself do not have a scientific background. Boomer is right to say nothing is a steady state in an aquarium.

Early on in the building of one of my tanks I took the advice of a friend and used well water instead of RO. Big mistake. I looked to a friend of mine who happens to be a chemist and he showed me that my carbon hardness was over 25 because of the disolved minerals. Anyway, with his help I rescued that tank and got it back to normal levels.

If I have any advice it would be find a LFS that you trust and does free testing. Work with them to correct any issues you might experience with water parameters. You will learn as you go. I stay way from people that think they know everything and state everything as an absolute. I, myself, try never to claim to being omnipotent!

Best of.......
 
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xspeedrj

Member
TylerHaworth said:
Speed - he was stating, however, that a dkh supplement WILL cause pH to rise...
Click to expand...


I thought he was indicated that I was claiming it has a lasting effect. My experience with buffers is exactly that. It can effect other parameters but only within the range it was designed and may not have a permanent effect.
 
Boomer

Boomer

Reef Sanctuary's Mr. Wizard
speed

If you look at my reply I indicated that it should not affect PH in any significant way.

It most certainly can affect the pH in a significant way. I thought I stated that but did not. But I did say this

"Any buffer will raise the pH some and some more than others."..which means some have an affect on pH and it is more than significant. If you add a buffer and it raise your pH 0.2 pH units that is very significant.


It depends on the buffer being added. Molar value wise, Baked baking Soda/Soda Ash has twice the Alk as Baking Soda and a higher pH. The pH of BS as I said is 8.3 and is like 11.5 for SA. Any buffer sup's we use will raise the pH. Some less just like some raise the Alk more and others less. There are also buffer sup's that lower the pH, such as Sodium Biphosphate. However, if one knows and understands what they are adding then using less or more can cause less of an issue with pH or Alk produced from that buffer.


It can effect other parameters but only within the range it was designed and may not have a permanent effect.

I do not know what you mean by that, give me an example.


I thought he was indicated that I was claiming it has a lasting effect. My experience with buffers is exactly that

It *may have a lasting effect, it depends on the tank. Case in point, which I'm sure you are aware of. In a SPS tank the buffer/Alk will drop like a rock if it is not sup'd. That is not a "lasting effect". You take a FOT with just a couple of fish and feed it correctly the Alk can last a long time, same for pH. You overstock that tank with fish or fish and food that buffer/Alk and pH will drop like a rock, also not a lasting effect. This why we tell people if your pH is OK use BS for Alk, as it has the least impact on pH. If the pH is not quite right and the Alk is not quite right use a mix of BS and BBS/SA. If it is an issue of both low pH and Alk then just BBS/SA. Most buffers sold in this hobby are ~ 6-1 BS to BBS/SA.




Tyler

What would you recommend my first plan of action would be? Mg testing... And if it is low, Mg supplementation? Or something else?

You first need to measure it to see where you are at. For beginners just Kent Marine Tech M. Try to keep the Magnesium ~ 1300 ppm. If it is lower than that it can be safely raised 100 ppm / day.

This works out very nice for most

Reef Chemistry Calculator

I'm very wary (scared and ignorant) of jumping into the realm of additives, but understand it's a necessary evil that must be conquered eventually - I just want to do it the right way the first time, and before the problem gets way out of hand!

There are 8 things that always need to be tested for in basic reef chemistry.

Ca++, Mg++ , Alk, pH, PO4, NO3- , Temp and Salinity




A good list of what.

Reef Aquarium Water Parameters by Randy Holmes-Farley - Reefkeeping.com
 
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TylerHaworth

Active Member
Thanks so much Boomer, those links are awesome...

Theoretically... if my Mg tests out to be at a good level, that calculator is saying I can raise my Alk up to 9-10 using Baking Soda with only a marginal drop in pH... I would assume this would be a desirable route since my pH is a bit on the high side anyway?
 
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