pH - Alk: help please

[starseed]

After having used the Kent 200 gallon buckets with no Alk, my tank is fuctuating like crazy.

pH

I just bought a Ph Probe 3 days ago.

My Ph is at 8.0 first thing in the morning and 8.25 by the evening.

This seems like a very big swing to me.

What can I do to stabilize my pH. I've been dosing Kent pH to raise it.

What is the most desirable pH level? 8.0, 8.1, 8.2, 8.3, or 8.4

Alk

My Alk was at 5.6 KH when I caught the Kent problem.

I have been dosing Kent Alk buffer and have only been able to get it up to 7.0.

What is the most desirable Alk level? Seems like 8 KH to 11 KH is quite a wide range. What sould the goal be.

 

[Randy Holmes-Farley]

My Ph is at 8.0 first thing in the morning and 8.25 by the evening.

This seems like a very big swing to me.

That is fine. pH between 7.8 and 8.5 is OK, and preferably above 8.0. The swing itself does not matter, IMO.

I recommend 7-11 dKh for alkalinity. If anyone claims any particular value is optimal, it is just opinion. Corals will likely calcify faster at higher alkalinity, so if you want faster growth of some corals or coralline algae, aim for the high end.

This article may help:

Reef Aquarium Water Parameters
http://www.reefkeeping.com/issues/2004-05/rhf/index.htm

 

[starseed]

Great!

So my pH low of 8.0 and high of 8.25, shifting through a 24 hour period, is not going to stress sensitive inverts and is considered stable - Right?

OK - My Alk is at 9.3 KH right now - that's good, but for more coral growth I can slowly raise it to 11 KH - Right?

Will a higher KH help keep the pH a little more stable?

And, sensitive inverts aren't stressed in any way whether KH is the recommended low of 8 KH to the Recommended high of 11 KH?

I thought I understood the pH - Alk stuff, but Kent has forced me to brush-up on my understanding of it.

 

[Randy Holmes-Farley]

So my pH low of 8.0 and high of 8.25, shifting through a 24 hour period, is not going to stress sensitive inverts and is considered stable - Right?

It is considered fine, yes. Some folks have a smaller swing due to more aeration and/or higher alkalinity, but yours is not a reason to change anything.

Will a higher KH help keep the pH a little more stable?


Yes. The higher the alkalinity, the more stable the pH. Also, the higher the pH the more stable it is as buffering is stronger at the high end of reef aquarium pH ranges. I discuss these issues in this article:

Boron in a Reef Tank
http://www.advancedaquarist.com/issues/dec2002/chem.htm


And, sensitive inverts aren't stressed in any way whether KH is the recommended low of 8 KH to the Recommended high of 11 KH?

Not that I am aware of.

Low pH and low alkalinity together can stress calcifying organisms. So if you keep ph at the low end of the recommended range, i wouldn't recommend that you also keep alkalinity there.

 

[Casperson]

Randy,
Whats the best way to raise PH wihout raising Alk. Buffer (Seachem Maine buffer) I've used have raised my alk as high as 20dkh just to raise my PH 0.3. My PH is 8.0, alk its 10dkh. I would like to get to 8.3-8.4 without rasing my alk to much more.

Thanks,

Tom

 

[Randy Holmes-Farley]

pH is best raised by aeration with fresh air, or with limewater. Buffers are not a good way.

This article has more:

Low pH: Causes and Cures
http://reefkeeping.com/issues/2004-09/rhf/index.htm

 

[starseed]

Thanks,

OK - So to start, I'm goin g to focus on raising the Alk to 11 KH.

I have 3 products for increasing pH and/or Alk, but now I am a little confused.

1) B-Ionic - I have 2 big gallon B-Ionic containers (am thinking of switching to the DYI version when out). After reading your articles, I understande that B-Ionic will not raise alk, but keep it at normal levels. That's also my expereince, it maintains the current Alk and Cal. So I don't think adding more if the Alk solution is the best way to raise my Alk.

2) Marin Aquarium pH Buffer by Kent (contains carbonate, bicardonate, and borate salts) I dosed this for 2 days - it really didn't raise my Ph, but did raise my Alk a little. Sould I use this one, then next one, or another product?

3) Coral Builder by Kent (containts carbonate and bicardonate) I also dosed this for 2 days - it really didn't raise my Ph, but did raise my Alk a little. Sould I use this one, the last one, or another product?

I'd like to get my Alk up tp 11 KH to help stablize my pH and increase coral growth.

Also, does a skimmer (size appropriate for water volume) solve airation issues? (I know it won't if the CO2 is low in the surrounding air)

 

[Randy Holmes-Farley]

B-ionic can be used to raise alkalinity, but if you try for too big of a rise, the pH will get high. Other than high pH, however, it is a good choice.

The Kent marine buffer isn't a good choice for a reef aquarium (due to the borate), but in a pinch it can be used to boost alkalinity and not pH.

The Coral builder is a good choice for a reef aquarium, and can be used to boost alkalinity, but not pH.

Baking soda is a fine choice as well.

Skimmers are a good way to aerate, but as you mention, if there is excess CO2 in the air, that alone won't help.