Kh and calcium problem

[Tony Lacey]

I have been measuring KH with two different test kits, one being Hagen and the other Salifert.
Hagen results are shown as ppm and my result is around 140. The Salifert kit results are in dKH or meq/l and show a dKH of around 14 or 5 meq/l.

The link (OZ reef) at the bottom of this message shows how the different units compare and at this stage I am a bit confused.

Clearly it isn't possible to have the two results that I have and at this stage I believe that the Salifert kit is probably the one to rely on. The reason being that I have been trying to raise my calcium level, which is currently about 370, with Kent marine Turbo Calcium with no effect. Could this be due to the interaction between a high kh and my adding of this product?

Do I need to reduce my kh first before building the calcium and if so what is the best way?

I'm learning the basics fast but am a bit lost here. Any help would be appreciated.

Thanks.OZ Reef

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[randy holmes-farley]

I too would suspect the Salifert test more accurate based on what I've heard from others and the company reputation, but I've never used either and cannot know for sure in your case.

The reason that you are having trouble raising calcium could be precipitation as CaCO3, or it could just be that you are not adding enough.

In either case, the answer is to add more calcium chloride, assuming that you have confidence in the calcium measurement.

[ April 19, 2002: Message edited by: Randy Holmes-Farley ]</p>

 

[Tony Lacey]

Thanks for the advice.

I have not been experiencing any precipitation so I will try adding more of and more frequently the Turbo Calcium. To date I have been adding small amounts, about 1/4 of a tea spoon every few days, as directed on the product.

I'll try changing this and see if things change.

 

[CraigBingman]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by Tony Lacey:
<strong>I have been measuring KH with two different test kits, one being Hagen and the other Salifert.
Hagen results are shown as ppm and my result is around 140. The Salifert kit results are in dKH or meq/l and show a dKH of around 14 or 5 meq/l.

The link (OZ reef) at the bottom of this message shows how the different units compare and at this stage I am a bit confused.

Clearly it isn't possible to have the two results that I have and at this stage I believe that the Salifert kit is probably the one to rely on. The reason being that I have been trying to raise my calcium level, which is currently about 370, with Kent marine Turbo Calcium with no effect. Could this be due to the interaction between a high kh and my adding of this product?

Do I need to reduce my kh first before building the calcium and if so what is the best way?

I'm learning the basics fast but am a bit lost here. Any help would be appreciated.

Thanks.OZ Reef

--------------------</strong><hr></blockquote>

Hi. I think that I need more information about how you are maintaining calcium and alkalinity in your system before I can help much. My gut feeling is that you simply haven't yet added enough calcium to the system to see it with your test kit. I should also warn you that some calcium test kits are difficult for some people to read.

So, tell me a little more about what you are doing and your calcium test kit, and I might be able to be more helpful to you.

I'll also give you the "conclusion" from a club talk that I gave last weekend. This is (more or less) the summary slide from my section on diagnosing calcium and alkalinity problems in a reef tank.

1. Make sure you have enough salt in your water.
(For the vast majority of reef tanks, the salinity should be S=35, which corresponds to a temperature corrected specific gravity of around 1.026.)
If you don't have enough salt in the tank, the concentrations of all of the major ions will be low, including calcium.

2. Be sure that you really have a problem. If that calcium test kit is two years old, chances are that the titrant has partially evaporated and you are reading artifactually low values. Do a two-fold sample dilution with pure water and be sure that the value you get is really half of the value that you get when you run a full-strength sample through the method.

3. Calculate where your system is in calcium/alkalinity space using one of my old aquarium frontiers articles. Figure out how much calcium you need to get on a NSW line. Add part of it, say a third, and retest for calcium. If you haven't moved a third of the way towards your target, then something is messed up. It might be with your calculation, your estimation of water volume, or your test kit.

4. Use what I have called "balanced" calcium and alkalinity methods to maintain the system.

If you have more questions, just ask.

Craig

 

[andy-hipkiss]

FWIW this page does the Ca/alk balance calculation for you ...

http://www.andy-hipkiss.co.uk/caalkcalc.htm

HTH

 

[Tony Lacey]

Craig,

Thanks for the reply.

Some of the facts about my setup are as follows:

Juwel 180L, Ph 8.1, dKH 13, 24c, sg 1.0245, salinity 35. 20kg Fiji rock. No corals yet but one clown and an angel. Tank has been running two months.

Everything has been very stable since the beginning and I am hoping to add a soft coral or two. According to my Salifert calcium test the results are always around 360/370 and I would like to increase this to around 400 or over.

I'll continue to add more calcium and I'll get back to you when I have done more reading.

Thanks.