Re: Alkalinity Buffers 10/20/07
Hi James,
<Hello Scotty>
Thank you for the fast response.
<You're welcome.>
Along the same line of thought, I have read much on the topic of pH and buffering, and it has been written that in addition to testing pH and alkalinity, that one should also test acidity. My question is where do I find an acidity test kit I have tried several online stores and have even Googled the subject and cannot find an acidity test kit anywhere. All I can find is that most companies refer to pH as a measure of acidity.
<pH is a measure of both acidity and alkalinity with pH 7.0 being neutral. Readings under 7.0 are considered acidic and readings over 7.0 are alkaline.>
Confused,
<Not any more, but do read here. http://www.wetwebmedia.com/marphalk.htm James (Salty Dog)>
Scott

Alkalinity Testing Meters?   8/26/07
Hello, Crew.
<Bob>
Like many color blind aquarists, I have trouble reading the subtle color changes (titration method) when doing water tests. Calcium and alkalinity being especially difficult (I use Salifert test kits for both). I have researched and discovered a number of water testing meters from Pinpoint, and even a phosphate meter made by a company called Martini Instruments.
<Like that name>
Any experience or thoughts on these companies products (or others?)?
<I like the Hach, LaMotte (and co.s that re-label their products) simple/r colorimeters, spectrophotometers and kits that go with them>
Also, I have not been able to uncover any equipment/meter capable of giving me an alkalinity reading.
<They are about... see the above's websites...>
Are you aware of any? If not, any recommendations on a traditional test kit for alkalinity that might have a more obvious reading/color change than the Salifert kit?
Thanks for your thoughts!
Bob
<And take a read on WWM re this issue... the indices, search tool... Bob Fenner>

Check my math... 15 ml.s equals 1 tbsp., 1/2 fluid ounce... – 06/26/07
Hey guys,
<Wes>
Sorry I seem to be bugging you guys a lot lately, but I think most of my questions haven't been repeats or stuff found through searches. I'm not going to ask you for how to save my little Nemo from the white spots he's got...
<Heeee!>
I try to read a TON before asking anything. Anyway, I have a question regarding alkalinity and the use of sodium bicarbonate. I understand that just using this and Kalk would create an imbalance with extra Na, and that the two part solution solves this by using CaCl for the Cl to balance the Na. Well, what happens if there's too much Na in a tank?
<Hopefully gets diluted through time via water changes...>
Secondly, I'd like you to check my logic/reasoning here. I have a 30 gallon system (aprox actual gallons after rock, etc), according to Reef keeping online magazine, a mixed tank using recipe 2 requires about .6mL/gallon, so 15mL/daily. 15ml = about .75 cup or 6oz.
<Mmm, no... way off. Please see here: http://www.exploratorium.edu/cooking/convert/measurements.html>
128 oz/gallon so suggested dose is .046gallons/day. The concentration suggested is 1 and 1/8 cup of Baking Soda per gallon. This equals 54 teaspoons. So, am I supposed to be dumping almost 2.5 teaspoons of baking soda into my tank daily?
<No>
That seems like a lot... Would there be considerable harm if I keep up regular waterchanges and use baking soda and CaOH for a few months? I do 5-10% w/c every few days. I will continue to check Ca and Alk levels to monitor for funkiness.
Sorry if that was long winded, but I don't want to be putting anyone in my tank in danger, and I'd like to keep my alkalinity a bit higher and steady than I get with just Kalk, w/c and the occasional buffer. Oh, and for the record, my Ca stays around 420. Also, I am having a bit of my coralline die off, but I believe that's because I went a little too long before switching out lights and it's not used to it yet. Sound logical?
<Please have a read here: http://www.wetwebmedia.com/corallinealg.htm
and the linked files above. Bob Fenner>

I'm confused or it's a misprint... Mmm, the latter, alk. conv.... need to find/match   – 2/26/07
Greetings Crew,
First off I'd like to thank Everybody (I hope I didn't leave anybody out). WWM is one of the most valuable tools I've come across in my quest to someday become a reef aquarist extraordinaire.
<Heee! You're on your way!>
Over the last couple of years, I've spent much time reading books, searching the Internet, reading the Internet, even conducting a few experiments. I've always resisted the temptation to ask any questions which have presumably/formerly been answered, or that I deemed more advantageously answered through experimentation. I'm averse to asking for an explanation regarding a topic that has been thoroughly discussed. That being said, I'm now in need of elucidation.
While reading the daily FAQ for 02/25/07 I habitually followed this link:
http://www.wetwebmedia.com/nitratesmar.htm
The link was part of the response to a question about Deep Mud Bed for NNR. In the linked article there is a brief paragraph which mentions alkalinity affecting the metabolism of nitrifying and denitrifying bacteria. That paragraph states ..."(about 5-8 dKH is about right, no higher than 12, and you can multiply these units times 2.8 to get the approximate values in milliequivalents per liter)"....
<Thank you for this...>
The way I read that, it seems to contradict everything I've learned in the past about the relationship between dKH and alkalinity. It's always been my understanding that dividing dKH by 2.8 could give you an approximation of alkalinity in milliequivalents per liter, or by multiplying alkalinity in milliequivalents per liter by 2.8 you could get an approximation of dKH.
<Yes... the conversion ratios are as you state... and the desired levels more like 8-12DKH...>
Is the text that I quoted from the article a misprint?
If not, can you clarify?
Thanks for all your hard work and commitment,
Ted
<Thank you Ted... will find/attach your correction... In previous years (and I wish they were back!) there were other folks that helped place a good deal of the responses... some w/o critical thought. Bob Fenner> <<RMF couldn't find...>>

ALK measuring...ppm or dKH? and don't forget meq/l
Hello everyone! Tonight I spent a few hours reading at your site about "Understanding Calcium and Alkalinity", and the differences between alkalinity and Ph. Well, I finally got it!
<very good to hear!>
Thank you for sharing your collective brains and education.
<hmmm... there's a joke in there somewhere <G>>
It's such a good feeling when something finally "clicks". Now, I feel that I can move forward, (even if just a few baby steps) into the vast world of reef keeping. But of course you know I won't let you off the hook that easily, I have one question for now.
I use "Aqua Lab I" test strips to measure my ph/Alk. What puzzles me is that when I see measurements at your site for Alkalinity, I see this symbol, "dKH". On my Aqua Lab test strips, they measure as ppm., like this: 0-80-120-180-240-300. Do these numbers convert into the alkalinity guidelines of 8-12dKH? I hope you're following me. As always, thank you! Pamela
<indeed Pam... there are several ways to measure hardness (general and carbonate) and as ppm (parts per million), dKH (German degrees hardness) and meq/l (milliequivalents per liter). Most test kits have conversions (the numbers/factors) in the fine print of the instructions for you... somewhere. My advice would be to get comfortable with dKH or meq/l ranges as they are most commonly used in popular literature. At last... no worries, you can convert any at will to another. Do consult your test kit (and in ppm target over 300 ppm. Actually closer to 400ppm for marines).>
                 
Re: ppm or dKH?
Got it! dKH:  To convert degrees of German hardness (dKH) to parts per million (ppm), multiply by 17. To convert degrees of German hardness (dKH) to milliequivalents per liter (meq/l), divide by 2.8. This means my tanks dKH is 11! Hence my notoriously low ph of 7.8! This is the reason I bought Kalkwasser, which I used tonight for the first time. I used the slurry method. Next question: If my calcium is already high enough, will the Kalkwasser keep pushing it up? At the present time it's a whopping 420! Thanks Pamela
<I see the light bulb shining over your head from here <G>. Learning really is fun! (and we are such nerds!). Actually... your 11dKH and 420ppm Ca are quite good together. Only the hardcore stony coral keepers want/need higher dKH. Too much Kalk will push your Ca scary high... lets just try aerating your tank better to increase pH. Verify that this is the problem by testing a glass of aquarium water before and 12 hours after vigorous aeration. If the pH increases... you have a CO2 problem or lack of aeration. Common this time of year (and summer too) with sealed and well insulated houses. A better skimmer or an extra vigorous airstone in the tank/system alone can raise the pH without needing any more supplements. Do try this first. Best regards! Anthony>

How many meg/L   =   dKH  ?
It seems there are two standards for alkalinity measurement, and I'd like to know how to convert one to the other so I can better understand folks in the FAQ section of the website.
I've been reading about 3 hrs/night for a week now and am learning a great deal.  Thanks Steve
<Great! 1 meq/L = 2.8 KH, GH, dH, dKH.  So 3.5 -5 meq/L = 9.8 dKH - 14 dKH.  Your Seachem test will read meq/L.  Craig>  

- dKH to ppm -
Good day, the crew rules.  Can't find a conversion cart for dKH to ppm.  Only found this formula 2.8 dKH =1.0 meg/l = 50 ppm.  You know if that's a linear relationship i.e.  (200 ppm = 4 meg/l = 11.2 dKH) or know where I might find a table?  Any help as always is greatly appreciated, Thanks.
<Found a calculator! http://saltyzoo.com/SaltyCalcs/AlkConv.php?units=DKH&dkhStr=8  Enjoy! -Kevin>

- Alkalinity Madness, Follow-up -
Well, here is the FAQ -
"Alk/Calcium
Hi gang, hope everything is groovy.
My alkalinity reading is 60 mg/l (I'm using a Hagen test kit). Does that mean ppm? What is the conversion equation for dKH or meg/l? (sorry, I've never tested Alk in the past).  Also I can't seem to get a reading on my Calcium (readings are indicating sky high, which is improbable) as I use a Hagen test kit for that also. Is there a better/best kit?
Thanks, you guys rock..  Justaguy
< Hey Justaguy!  Craig here, and feelin' groovy.  The equivalents between measurements is as follows:
1mg/L = 0.02meq/L  Americans measure alkalinity in meq/L  The German hardness scale is dKH.
So, at 60mg/L X 0.02= 1.2meq/L. so using the measurement you got from the Hagen kit your alk is 1.2meq/L VERY LOW.  Most keep calcium around 425-475 calcium and Alk at 3.5 to 5 meq/L (1mg/L=0.02meq/L). Also test pH regularly as well.  I suggest purchasing quality test kits to ensure accuracy.  Salifert and Seachem are two excellent brands.  Have Fun!  Craig>"
So, again, following these guidelines, my alk. would be 3meq/L, is this right? <It was my understanding that your test kit was measuring KH [carbonate hardness] which is 1:1 to dKH [German carbonate hardness]... does your kit measure in some other unit?> There is a difference between meg/L and mg/L right? <Yes.> How are you getting 54ish?? <By converting from 150 KH.> What is the correct formula. <Not sure - I use an online calculator because I just don't have time to do anything else: http://www.saltyzoo.com/SaltyCalcs/AlkConv.php>
How could I possible have 54ish? <Again, was working on the information you provided which said "I dropped 15 drops to color change.  Kit says, to get KH, multiply number of drops by 10." - that's KH, same as dKH which is what I plugged into the calculator - I could have misunderstood, it wouldn't be the first time.> Thanks crew!  Micah
<Cheers, J -- >

- Alkalinity & Testing For Such -
Dear, alkalinity Guru:
I purchased the Hagen/Nutrafin carbonate hardness test kit ($15), it measures in terms of KH.  I dropped 15 drops to color change.  Kit says, "To get KH, multiply number of drops by 10."  That's 150 mg/L. <Uhh... that's 150 "KH" if I'm not mistaken which is 54 meq/L.> Test kit says anything beyond 125 mg/l is unusually high and to contact my aquarium specialists (that would be you guys!). <A KH of 150 is abnormally high.> I read in your faq to convert mg/L to meg/L, multiply by .02   ...  that gives me 3meg/L   ....  in the same faq it says ideally, the level should be between 3.5 & 5meg/L <That much is true.>  .....   so, I would be on the low side, I guess? <I couldn't find the exact FAQ you were looking at, but methinks there is a small mistake in there somewhere... your kit measured a KH of 150 - that's a meq/L of 54-ish - that is on the high side of high.> is the test kit mistaken in what the ideal level should be? <I think perhaps it is you that is mistaken, not the kit. I'd run the tests a couple more times to be certain - if the numbers stay consistently high, you need to stop your additive regimen and do a couple of water changes.> my calcium is approx. 400. <That seems unusual for such a high level of alkalinity - I'd run those tests again, because this sounds like a titration test, you should only add the reagent until there is a slight hint of color change - stir after every drop.> pH stays around 8.2.  I have Zo's & shrooms.  12 hour light cycle with 2 96 watt pc's. 1 actinic.  thanks crew!
<Cheers, J -- >

- Accurate Alkalinity Test -
Hello all-
I have a question for whoever has the time. <Sounds like I'm next in line - JasonC here...> Ok, maybe 2 questions.
Alk: 7dkh or 10.5 dKH (this is explained in info below)
Ca: 300mg/l
Ph: 8.4
S.G. 1.025
I have been using the Aquarium Systems Fastest for checking alkalinity. I recently purchased a refill for the reagent bottle and it came with a different style tip on the bottle.
I used the tip that came with the new bottle and my alk reading was 10.5dkh. I put the tip from the old bottle on and the reading was 7dkh. The 7dkh is  the normal reading I have been getting with the old tip, (I have been trying to raise alk with ReefBuilder) but now it has me wondering if my past tests have been accurate and my Alk is REALLY 10.5 dKH not 7. I can see that the drops are a bit smaller with the new tip. <That is a bother... certainly drop size would be a factor.>
Is there some way I can check the accuracy? 3.5dkh seems like a big margin for error. I imagine you will suggest comparing against another kit. <You got it - a different brand would be best.> But who knows. <You could also ask the folks at the store to test it for you.>
As long as we are on the Alk subject, I change a little less than 10% of water every week.
I just started using deionized water a few weeks ago and I prep it as follows: (And I do the same with the top off water) aerate plain water for 24hrs, add salt, aerate another 24hrs, add buffer if needed. <I'd do that the other way around - buffer first, then salt.> I use ReefBuilder if Alk is low. Superbuffer if ph and Alk are low.  When I aerate water I use a 600gph pump with a small air pump hooked into the aeration nipple on the output. It moves the water around quite well. I was wondering if the water may not get aerated enough. Should I think about a bigger air pump? <I'm sure this is fine.>
In the main tank, it seems like I can not get Alk above 7dkh or Ca above 300ish without adding these supplements all of the time. I add Tech CB in main tank when Ca is low. It seems like the regular water changes should keep things more in line. <Regular water changes aren't necessarily going to boost calcium, but would keep it in stasis. If you have a good number of calcium consuming organisms, then calcium will get used up if you don't supplement it.> I will go through a ton of ReefBuilder and Tech CB if I keep this up. <Not uncommon, is why many people start using calcium reactors.>
Ca is always on the low side also. I will dose with Tech CB and Ca will be up around 400mg/l for a few days but then drops down again. <Sounds like you should be dosing calcium on a daily basis and not waiting for the levels to drop.> I know that Ca and Alk should not both be on the high side at the same time. And I also read that the Ca and Alk should be in balance before using Tech Cb. I am assuming that a Ca of 300mg/l and an Alk of 7dkh is in balance (both on the low side) and I am ok with adding the Tech Cb. <Yes.> But it seems like I am adding it quite often and not getting much results. <Again, is par for the course with this type of additive, and potential for consumption of calcium.> I am fine with spending the money as long as I am on the right track. <Consider that calcium reactor.> Am I? <For the most part yes, you're certainly not on the wrong track.> Ph is always around 8.4. It is the only one that is where I want it (or where it should be).
Hope all is great for you. :) Many thanks for your help.  Dennis
<Cheers, J -- >

Hagen KH test kit... and Xenia
Just like to say ahead of time, thanks for helping out!  Ok, here's my problem.  On the WWM website I have read many times that you want to keep the dKH around 8-10.  On my Hagen KH test kit it says that anything above 125 mg/L is too high.  When I convert 125 mg/L to dKH I get 7 dKH.  So, if I was to shoot for 8-10 dKH that would be at least 143.2 mg/L.  So what level am I supposed to aim for?
<you want to aim for 8-10 dKH>
My calcium is at 450 ppm right now and my KH is 130 mg/L (or 7.28 dKH). This is all assuming I did my calculations correctly, please feel free to double check my math!
<Why don't you try a test kit that is not so confusing. Try Salifert or Red Sea pHarm. (the reason I say this is if the test is a pain to use you will more than likely not test as much as you should) Also if the test kit is old it will give you incorrect readings (there should be a date on the package with expiration on it.>
  While I have you here, I have a question on a pulsing Xenia I have had my eye on.  There is a pulsing Xenia that I want at a LFS, but the LFS isn't really local!  It's about 1.5 - 2 hours away.  I heard that Xenia don't travel so well.  It's a large rock completely covered with Xenia and I would love to have it, but I don't want to get it home just to find I've killed it in transit.  Any help on how/if I should get it home would be great.  Thanks so much... again, and again, and again!!!
<you should have no problem bringing the xenia home. I would say bring your own Rubbermaid (in case they do not have large styros) or ask the LFS to place it in a  large styro and with lots of water.2 hours should be no problem. Remember to acclimate them slow once you get home.
good luck MikeH>
Steve

dKH Question
Thanks for the info, however I guess I still have a question on KH.  My problem is so much that I'm having trouble converting my KH from mg/L to dKH.  My problem is that my test kit says that anything over 125 mg/L is too high and WWM seems to say that I want 8-10 dKH.  8 dKH = 143.2 mg/L. So that would be much more than the 125 mg/L that Hagen says is too high. Why would Hagen say that anything over 125 is too high when it's actually low?  Again, thanks for all the help on this.  I need all the help I can get understanding these things!!! Thanks!
<Is the test kit saying that this is to high for fresh water or salt water. sounds high for fresh and low for salt. if it is for saltwater  don't know why it says that you want 8-10 dKH Mike H>
Steve

Testing High KH...
Greeting Crew,
<Scott F. with you today!>
I hope this has not been asked before, but I did spend time trying to find the answer before I sent this email. I have a new calcium reactor and want to test the affluent before installing into my system. I am tuning with freshly mixed salt water in my sink as I what to get it tuned-in so that I don't subject my reef to any mistakes. The information included with my Korallin reactor indicates that the KH of the effluent should be 25 to 60. Is there a way for me to test for this value as my Salifert test only measures up to 16 dKH? Dilution maybe?
<That might be a great idea. My other thought might be to try a test kit with a larger range (I believe La Motte kits have a pretty broad range). You may need to shoot an email or two to a manufacturer to get the stats on their kits...>
Thank so much for all the help. You guys have been instrumental in my success (8 months thus far) in reef keeping. Greg
<Glad to be a part of it all, Greg! Keep up the good work and feel free to contact us again any time! Regards, Scott F>

Question on Carbonate Hardness (KH)
I have a Hagen (KH) test kit and it says the ideal range for saltwater is 105 - 125 mg/l. I have been reading through the FAQ and you all say 11-12 dKH is good. Is there a way to take my numbers and turn them into the dKH numbers?
<Shawn... my apologies, but we are burring through queries today and I do not remember the conversion of the top of my head. Please refer to the instructions with the kit. Most manufacturers have conversions listed for meq/l, ppm and dKH. If not, let me suggest/trouble you to run it down on a keyword search on Google ("Hardness conversion")>

Alkalinity Measurement
Hello again,
I just did some water tests today: SG 1.025, Temp steady at 80F all day/every day, Ammonia 0.0-0.1, Nitrate 10-20 (I think I'm color blind), Calcium 435, PH 8.4... The alkalinity test (Red Sea) can be read (according to the colors on the box) as "very high" or about 3.2 meq/L...
<not "very high" if you are trying to grow corals. It is nicely elevated but not too high>
isn't there another way to read this measurement? dKH or something like that? 
<indeed... several ways (ppm, dKH) but won't change the facts. Your ALK is fine, my friend>
These tests (as are all my weekly/daily tests) were taken in the late afternoon. 
<fine... just be sure to test pH after a long dark period as well as "high noon">
I tried to do a search using the Google engine on your site to try to figure out the conversion formula, but it's close to midnight here in FL...I am tired, physically, but my curiosity prevents me from falling asleep. 
I have a 55g w/10 gallon sump, built in corner overflow, 2 sweeping power heads on opposite ends of the tank near the mid water level outputs pointed up, AquaC Urchin in sump (AWESOME SKIMMER!!!! 
<agreed>
More than a cup of blackness every day), about 55lbs of LR (mix of mostly Fiji and some Atlantic/gulf) been in less than a month (cured it myself), 220 watts of PC lighting no more than 3 inches from the surface with a big noisy fan, Chemipure (will also add use of Polyfilter on next carbon change), and probably one or two other things I can't recall at this time of night. 
<all very fine>
I do a 5 or ten gallon water change weekly using DI water, aerated overnight, buffered overnight, then salt added, left overnight, tested until parameters match my tank's. 
<excellent>
I wouldn't have done any of these things (testing, regular water changes, lighting, etc.) without the info from your site...thank you. 
<our pleasure>
I have a yellow tang, Kole tang, 4 damsels, Astrea snails, and blue legged hermits, 2 small serpent stars, one large green serpent (will trade this in once I catch him), two small but growing fast unidentified crabs, a pink carnation coral (hanging upside down in a small cave, about 8 inches from the sweeping powerhead running full force), a small Acropora (tan with what looks like pink or lavender tips...I'm so bad with colors) which is within the top 6 inches from the surface and about 10 inches away from a sweeping power head running full force, a small colony of yellow polyps, 2 flower anemones (will trade these in soon) and one BTA (in tank for almost two months, has not settled down yet). The fish have been there since November last year with last fish being Kole tang added in June. All Live stock are well (except for BTA). I was wondering if my alkalinity is too low? If so, do I just keep adding buffer until I get to...what? 4.0 meq/L?? 
<good heavens no! Really... just relax and enjoy this hobby my friend. For general maintenance, an ALK of 2.5-3 meq/l is fine>
I feel that my current parameters will hinder the growth of coralline. 
<nope... consistent levels of calcium and ALK even if slightly low will grow corallines jest fine. High but ire levels will impede. Again... enjoy your hobby... this isn't work :) You seem to be well-read and in a systematic habit with the tank... continue to do so: regular and reliable maintenance>
Am I worrying about nothing? 
<big-time!>
Or is my calcium/alk ratio good? The shells of all my snails show growth...does that count for something? 
<yes... especially to the snails<G>>
My only commercial additives are a product called Oceans blend, a two part Ca/Alk, and I dose Kent iodine once a week. 
<with weekly water changes all sounds fine>
Please help or point me to link to understand this better. I've read thru the calcium and alk articles, but will read again. Shout out to my peeps B.LOVE...keeping it real all up in his 75-G reef, aw-ite!
Yo-Yo-Yo, Thanx,
Randy M. Yniguez, MA
<word up, my salty brother. Anthony>

Alk/Calcium
Hi gang, hope everything is groovy.
My alkalinity reading is 60 mg/l (I'm using a Hagen test kit). Does that mean ppm? What is the conversion equation for dKH or meg/l? (sorry, I've never tested Alk in the past).
Also I can't seem to get a reading on my Calcium (readings are indicating sky high, which is improbable) as I use a Hagen test kit for that also. Is there a better/best kit?
Thanks, you guys rock..
Justaguy
Hey Justaguy!
Craig here, and feelin' groovy.
The equivalents between measurements is as follows:
1mg/L = 0.02meq/L
Americans measure alkalinity in meq/L
The German hardness scale is dKH.
So, at 60mg/L X 0.02= 1.2meq/L. so using the measurement you got from the Hagen kit your alk is 1.2meq/L VERY LOW. 
Most keep calcium around 425-475 calcium and Alk at 3.5 to 5 meq/L (1mg/L=0.02meq/L). Also test pH regularly as well.
I suggest purchasing quality test kits to ensure accuracy.
Salifert and Seachem are two excellent brands.
Have Fun!
Craig

Alk/Calcium
Hi gang, hope everything is groovy.
<yep... just as soon as I get my bong fired up>
My alkalinity reading is 60 mg/l (I'm using a Hagen test kit). Does that mean ppm? 
<nope><<Mmm, yes... mg/l is equivalent to ppm. RMF>>
What is the conversion equation for dKH or meg/l? (sorry, I've never tested Alk in the past).
<hmmm... I don't recall the conversion off by heart. Are you sure it isn't in the test kit literature. It surely must be... I've never seen a test kit that didn't have it>
Also I can't seem to get a reading on my Calcium (readings are indicating sky high, which is improbable) as I use a Hagen test kit for that also. Is there a better/best kit?
<definitely... I like Aquarium Systems brand Calcium test kit. Inexpensive and easy to read the titration point>
Thanks, you guys rock.. Justaguy
<best regards, Anthony>

Calcium and alkalinity question
Hi Craig,
<Hi Jun!>
Another question for you. I went to the LFS and have my calcium and alkalinity (is KH and dKH the same?) tested today. My Ca level is 320 and KH/dKH is 160. What do I have to do to get my alkalinity level and Ca level to an acceptable level. Thanks again (just as I promise more questions to come)......Jun A.
<Okay. dH, GH, KH, and even dKH are alternate terms the Germans gave us for measuring alkalinity, they are the same. <<Mmm, no. RMF>> I think you may have your alkalinity test results goofed up, perhaps expressed as dKH when they meant meq/L, or missing a decimal point? Is it 16.0 dKH or 1.60 meq/L? Based on your tests and your Toadstool acting up I'll bet your alk is 1.6meq/L. Please double check. If it is 1.6 it is VERY LOW and you need to get a good Marine Buffer like Seachem Marine Buffer to keep your alkalinity at 3.5 - 5 meq/L (10 - 14 dKH) ASAP. Please test your pH as well which should be 8.3 -8.4 just before the lights go off. Calcium should be around 400-450 mg/L. Seachem makes a good calcium supplement called "Reef Advantage Calcium" which is a good product. Follow the label directions exactly for dosing. I would also recommend investing in a few good quality test kits so you can maintain your water in top condition without stressing your inhabitants (or waiting to go to the fish store). Seachem and Salifert are favorites. Please read more about alkalinity and calcium at WetWebMedia.com. There is much to learn! Craig>

Re: 75 Gallon Reef System
I wanted to thank you for replying to my email, and also I did have a couple of other minor questions. One being that I have noticed that when I was using tap water for topping off my system, that the alkalinity was naturally higher than when I have used distilled water.
<Sounds reasonable, doesn't it? In the short term, consider the simple addition of... baking soda! Yes, cheap sodium bicarbonate... to make up most all the alkalinity you and your corallines need.>
My other question would be if you knew of any test kits that are more precise in there readings than just by matching color. I have trouble obtaining a good match by comparing colors obtained from readings and the colors on the scales. For instance Ph readings. I suppose the probes would be the only way to get a more accurate analysis of the true values.
<There are amperometric, spectrophotometric et al. types of test gear that are definitely more precise and accurate... but not really justifiable expenses for aquarists use... Instead look into better Colorimetric assays... companies like Salifert, Hach... and you'll do fine. Believe me, these are what I use.>
Thank You 
Matt Smith >>
<You're welcome my friend. Bob Fenner>

Hagen test/ tang /DOC questions
Greetings and happy holidays Bob!
I have written before about the 100 gallon tank that has the hair algae problem (440 w of VHO, T1000 skimmer, 2' sand bed, 100 lbs. LR, a decent amount of feather Caulerpa in tank and lots of Sargassum). I did take your advice and added a Salarias fasciatus a week ago. He's a funny little guy. . . so far he has managed to make the pump returns spotless and the tank walls but I never see him eat on the LR. 
<Time will tell... whether the species on the LR is palatable to this animal>
Other than a few mushrooms and some button polyps there is no other live stock. Therefore, the 2 3/4 month old tank has never been fed.
<Mmm, sufficient nutrient for much life can/does come from seawater, tapwater, substrate, the rock, other organisms being "cycled"...>
The skimmer is still pulling a considerable amount of DOC out of the water and I've done a 40% water change in the last month. Yep, I still have hair algae and there's a fuzzy kind of algae that grows on the front glass. Any suggestions for getting rid of the DOC? 
<Just keep doing what you're doing>
More water changes? 
<Some... if the nitrates become too much (tens of ppm)>
Right after Christmas I plan to add a purple tang (after quarantine) . I currently have" 0" readings for all the bad things and a 4 for nitrates. Does DOC affect tangs?
<Affects all living things>
I also want to add a few aquacultured Sarcophytons. Is the hair algae bad for them? 
<Not necessarily... their presence may in fact reduce the algal growth>
Lastly, my KH test is from Hagen. Every reference I find refers to KH in terms of small numbers (1-12 etc.) My test expresses the KH as mg/l. How do I convert to the numbers used in reference materials. My current KH is 120 mg/l. Thanks for all you do Bob. Have a happy and safe holiday season.
<KH can be converted to mmol/l of CaCO3 by dividing by 17.9
Bob Fenner>
David Dowless

Calcium/Alkalinity
Hello Wet Web Media Consortium ,
Never know who will respond to emails . I am still having a problem getting my calcium levels past 380 after about three weeks of dosing with Kent A and B solutions . All other parameters are within tolerances . I only have Live Rock in the tank with yellow tangs . The tank is a 120 with a large CPR wet/dry/protein skimmer . Any suggestions would be greatly appreciated.
<Use a Calcium Chloride solution to raise your calcium levels and then maintain it with the two-part solutions.>
Also I've noticed that your Alkalinity levels in FAQ are being measured in dKH , my test kit measures in meg/L . What is the correlation between the two?
<2.8 x meq/l = dKH>
Thanks for the help you guys provide thousands of enthusiasts around the world . Richard Atkinson
<You are welcome. -Steven Pro>

KH units
I have a question for you and that is how do I lower my KH.? I have bought a new test and my reading is 240 mg/l thanks in advance, dab
<I am unfamiliar with this scale. I have only ever seen alkalinity measured in German degrees of hardness (dKH) or milliequivalents per liter (meq/l). What brand is this and are there any conversions given with the kit? -Steven Pro>

Re: KH
this is a Hagen carbonate and general hardness test and now I see there is a conversion chart it was hidden in the flap in the box you multiply
reading times 0.02 to get meq/l I have a reading of 3.2 this is bad I think or at least very low?
<not very low... in fact, just barely on the low end. Really nothing much to worry about. If you have a full reef tank... get the alkalinity up with regular additions of Seabuffer (tm) or two part liquid calcium mixes. Have faith, my friend. You're fine. Anthony>

Alkalinity
Hi Bob, me again.
<Anthony Calfo in your service>
Thank you for your previous help. I have a problem getting the Alkalinity reading below 140, 
<not sure of the measure you are referring to here...ppm? Else, target through conversion a dKH of around 12, or approaching 4 meq/l>
my other readings are as follows. 176 litre tank, Temp 24.5, S.G 1.024, pH 8.1, Ammonia 0, Nitrite 0.2, Nitrate 10, Phosphates 0.25, Calcium 360, Iron 0, Alkalinity 140. 
<hmmm... the pH is also low (needs to be higher... like 8.3 by night and 8.6 by day)... your phosphate is also high enough that you should expect nuisance algae soon if you don't already have it.>
The tank is four weeks old and I do a 20 litre water change every week, for some reason I am unable to get the Alkalinity down. There are two domino fish along with six red leg hermit crabs and six turbo snails. Could you please advise on what to use to get the alkalinity down to about <125. Many thanks Colin
<Colin, high alkalinity is rarely a problem.. I believe you've been misguided on this point. Furthermore, you calcium is fine but just about on the low end. You may want to consider using a two-part liquid calcium supplement that will take care of Ca and Alk like B-Ionic or Sea-Balance. Best regards, Anthony> 

KH and dKH
I have an Alkalinity test kit that measures in KH <carbonate hardness> and not dKH. (I think its KH, the measurement is in the 100 -120 range) I want to be able to translate that to dKH because that is what most recommendations are given in.<Alkalinity should be around 8-12 dKH> Is there an easy formula for this?<Found this link for you hope it helps http://www.chaoticreefer.com/TestKits/SalifertAlkalinity.htm >  Or can you provide a recommendation on alkalinity level for a reef tank in KH? <8-12dKH is recommended>
Thanks.<IanB>