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SteveNMegz
03/22/2008, 10:54 AM
Hey guys, we've been testing our carbonate hardness and our results are in MG/L.

our results are always between 110 mg/L, and 120mg/L.

Would these results read a 11-12DKH????

or is there something else we have to do to switch it to DKH?

Thnaks!

aquaman67
03/22/2008, 10:59 AM
http://ozreef.org/library/tables/alkalinity_conversion.html

There are actually three units of measure for Alkalinity for some reason.

Most in reefing use either dKH (degrees of carbonate hardness) or meq/L.

PPM is rarely used, but they're all the same.

airinhere
03/22/2008, 11:03 AM
One meq/L = 2.8 dKH = 50 ppm CaCO3 equivalents.

Seawater has an alkalinity of about 2.5 meq/L = 7 dKH = 125 ppm CaCO3 equivalents.

What test kit are you using?

Your readings are in mg/L? not in meq/L correct?

If its mg/L I think your concept of 11-12dKH sounds plausable dependent on what test kit you are using.

(If you meant 11-12 meq you might have a serious problem).

SteveNMegz
03/22/2008, 11:05 AM
well it seems like we're falling really short then.

according to that chart we'd be at 6.5-7 DKH.

how is this possible? we have fish/coral/inverts living fine in there.

would high calcium have any part of this?

DevilBoy
03/22/2008, 11:05 AM
11 divided by 2.8 equals 3.92 meq/l. my dkh is 10 and comes out to be 3.5 meq/l

Randy Holmes-Farley
03/22/2008, 11:08 AM
well it seems like we're falling really short then.

according to that chart we'd be at 6.5-7 DKH.

how is this possible? we have fish/coral/inverts living fine in there.

6.5-7 dKH for alkalinity about matches the ocean, and is not a cause for concern, but you need to keep it from dropping lower. I generally recommend 7-11 dKH.

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

SteveNMegz
03/22/2008, 11:20 AM
we're using the hagen test kit, I jsut read through the book again and it says mg/L (ppm)

so I guess we have 110 ppm, which would give us 6.5DKH

we alway thought that the D in DKH was jsut a form of Deca so we though 110 mg/l would be 11DKH

is there a reason our DKH would be so low, and what are the advantages of raising it?

snorvich
03/22/2008, 11:22 AM
What salt are you using? Various salts have varying amount of Mg Ca Alk. If you start low, you end up low.

Aquarist007
03/22/2008, 11:27 AM
<a href=showthread.php?s=&postid=12152100#post12152100 target=_blank>Originally posted</a> by SteveNMegz
we're using the hagen test kit, I jsut read through the book again and it says mg/L (ppm)

so I guess we have 110 ppm, which would give us 6.5DKH

we alway thought that the D in DKH was jsut a form of Deca so we though 110 mg/l would be 11DKH

is there a reason our DKH would be so low, and what are the advantages of raising it?

are you using ro water or tap water?

airinhere
03/22/2008, 11:28 AM
The answer to that gets very involved very quickly.
And the answer can only be determined by tailoring it to your individual tank and its occupants.

Best bet is to go looking for articles written by Randy in past issues of RK magazine. http://reefkeeping.com/

SteveNMegz
03/22/2008, 11:28 AM
were using coralife.

calcium always reads between 560-620, we were assuming this was because of the salt also

Randy Holmes-Farley
03/22/2008, 12:01 PM
is there a reason our DKH would be so low, and what are the advantages of raising it?

Unless you are supplementing it, that is where it typically ends up as organisms use it, and then start to slow down their use as it drops below 7 dKH.

All reef aquaria need alkalinity supplements of some sort or other. Without it, organisms that deposit calcium carbonate skeletons cannot grow. I discuss that in the article linked above. :)

Yes, the high calcium probably comes from the mix. If those values are accurate, I'd just supplement alkalinity while you let the calcium decline slowly as organisms use it. :)

SteveNMegz
03/22/2008, 12:10 PM
yup, we are using RO water. do you recommend any good buffers for this? and should it be added directly to the tank?

Thanks for all the help everyone!

DevilBoy
03/22/2008, 12:16 PM
yes you can add straight ro/di water to the tank for top off of evaporated water.

Randy Holmes-Farley
03/22/2008, 12:59 PM
If the goal is to supplement alkalinity when calcium is already on the high side, baking soda from a grocery store dissolved in a little of the RO water is as good as it gets.

This calculator shows how much to use for any given boost to alkalinity that you want:

Reef chemicals calculator
http://home.comcast.net/~jdieck1/chem_calc3.html

reefergeorge
03/22/2008, 01:06 PM
<a href=showthread.php?s=&postid=12152678#post12152678 target=_blank>Originally posted</a> by Randy Holmes-Farley
baking soda from a grocery store dissolved in a little of the RO water is as good as it gets.
http://home.comcast.net/~jdieck1/chem_calc3.html

I have read that you can bake the baking soda on a cookie sheet at 350 for 30 min. \
What does it turn into, and is it better?

aquaman67
03/22/2008, 01:43 PM
<a href=showthread.php?s=&postid=12152730#post12152730 target=_blank>Originally posted</a> by reefergeorge
I have read that you can bake the baking soda on a cookie sheet at 350 for 30 min. \
What does it turn into, and is it better?

It turns into "washing soda".

Baking soda is sodium bicarbonate. Washing soda is sodium carbonate. Baking it drives off one of the carbons.

The pH of baking soda is about 8.

The pH of washing soda is about 12.

Overdosing baking soda isn't too bad.

Overdosing washing soda could be horrible.

If you use washing soda, be extra, extra careful.

Randy Holmes-Farley
03/22/2008, 02:22 PM
I have read that you can bake the baking soda on a cookie sheet at 350 for 30 min. \
What does it turn into, and is it better?

Neither is "better" for all uses. As mentioned above, if you want it to raise pH as well as alkalinity, bake it first. if you just want to supplement alkalinity, don't bother :)

SteveNMegz
03/22/2008, 09:08 PM
thanks for all the help guys!

we're going to do the baking soda method after we read all of the articles a few times lol. Just another question....
are parameters right now are...
amm-0
nitrite-0
nitrate-0
phosphate-0
PH-7.8 (during mid-day)
calcium-560
alk 6.5DKH
mag-unknown right now.

when we start dosing baking soda to up the alkalinity, what else should we be watching for? our calcium should lower, right? and our PH would rise? anythign else?

thanks!

Randy Holmes-Farley
03/23/2008, 08:10 AM
Calcium will slowly decline as it is used up, and at some point you will likely have to start dosing it, unless water changes with a high calcium mix maintain it.

As you note, you may eventually want to measure magnesium. :)

otrlynn
03/23/2008, 09:22 AM
Not to highjack this thread but seems to make sense to ask this here instead of starting another thread. When I started with saltwater, I used Coralife salt b/c that was what the LFS carried. My calcium was always high, around the 550-620 range, as SteveNMegz noted above. At that time I also had few corals. I switched to Instant Ocean (which I notice dissolves more easily) as well as added coral and started growing Halimeda in the display. My calcium has dropped and I am maintaining Alk. and Calcium using Kent Marine two-part. No problems--maintaining good parameters. Here's the question: Would it be reasonable to go back to the Coralife salt (which seems to be high in Ca) and just use baking soda? Is it as effective as commercial reef buffer? I want to to right by the tank, but wouldn't mind saving some money. As part of this picture, I do weekly 8% water changes.

Randy Holmes-Farley
03/23/2008, 11:36 AM
Here's the question: Would it be reasonable to go back to the Coralife salt (which seems to be high in Ca) and just use baking soda?

Depends on your demand. The salt is not nearly enough even with a lot of water changes for a high demand tank, but may be enough with a low demand tank.

Baking soda is as or more suitable than many commercial buffers. If you want it to raise pH as well as alkalinity, you can bake it before using it.

I prefer to start with a salt mix (or a modified salt mix) that about matches the tank, and then use a balanced calcium and alkalinity additive system (two part, limewater, CaCO3/CO2 reactor, etc). Using a balanced additive leads to many fewer problems with calcium and alkalinity in the long run.

FWIW, I model using water changes to supplement calcium here, but i assumed it was 420 ppm, not 500+ ppm. Still, I expect the trend will be the same, but offset higher:

Water Changes in Reef Aquaria
http://reefkeeping.com/issues/2005-10/rhf/index.php

from it:

http://reefkeeping.com/issues/2005-10/rhf/images/Figure21sm.GIF

Figure 21. Calcium concentration as a function of time when performing daily water changes equivalent to 0% (no changes), 15% and 30% of the total volume each month (in other words, 0%, 0.5% and 1% per day). In this example, calcium is present at 420 ppm at the start and is depleted at a low rate of 4 ppm per day.

otrlynn
03/23/2008, 12:06 PM
Thanks Randy. So it sounds like one could use a mix higher in Calcium, like Coralife, measure the Calcium right after a water change and continue to monitor it until the time of the next weekly water change. If it remained above 420 until the next water change, it sounds like no additional calcium would be needed (and doing the water change would raise calcium again a little). Simultaneously one could be adding baking soda, or "baked" baking soda to maintan alkalinity. Is it a potential problem that the calcium would be in essence rising and falling (rather than being kept steady as when using a two-part)? Is this what you meant by your preference for using balanced additives to prevent problems in the long run?

Randy Holmes-Farley
03/23/2008, 12:38 PM
So it sounds like one could use a mix higher in Calcium, like Coralife, measure the Calcium right after a water change and continue to monitor it until the time of the next weekly water change. If it remained above 420 until the next water change, it sounds like no additional calcium would be needed (and doing the water change would raise calcium again a little).

Yes.

Simultaneously one could be adding baking soda, or "baked" baking soda to maintan alkalinity.

Yes, that is fine.

Is it a potential problem that the calcium would be in essence rising and falling (rather than being kept steady as when using a two-part)?

I do not think that is a problem, but will require unusually frequent and ongoing testing. :)

Is this what you meant by your preference for using balanced additives to prevent problems in the long run?

Partly. It sounds attractive to measure and dose calcium and alkalinity independently as needed. In practice, that often leads to a roller coaster of calcium or alkalinity too high or low, and too much number chasing. If you use a balanced additive and salt mix, you can go for months or more without testing and without too much risk of a big imbalance.

otrlynn
03/23/2008, 01:43 PM
Thanks Randy, sorry SteveNMegz, I guess this amounted to a thread high-jacking, hopefully you were learning too...

SteveNMegz
03/23/2008, 05:00 PM
not thread jacking at all otrlynn, this is great information for us also!

We've learned a lot from this thread!