This one's got me!! Nitrogenous test kits  – 06/07/07
Crew,
<Michael>
I have had a 20 gallon saltwater system set up for about 4 months. I ran into a problem about a month ago with high nitrites and nitrates. I moved the livestock to a QT tank and most of them made it (didn't have much since I just started, just 3 clowns,
<Better to just have two... a third will be brutalized in time...>
1 flame angel
<... not enough room for this species here>
and one red mushroom remain) I know, the flame angel will eventually go to a 200 g when we finally get that going, hopefully soon).
<Wait till then>
At the time I decided to upgrade the 20 g and install an internal overflow and hard plumb it to the 10 gallon sump below.
<Good practice>
Finally got that done about 2 weeks ago. For equipment I have the 10 g sump, a 4.5 g hang on back refugium with miracle mud and Chaeto, a Remora skimmer and about 25 lbs of LR. When I set up the new system I put in a new substrate of CaribSea Arag-ALIVE. The LR is fully cured and when I set up the new tank, I used about 16 gallons of water from the QT tank (55 g) to get the 20 g tank going again. Since I had a new substrate I figured the tank would have to cycle again.
<Likely so>
I have been testing everyday with Salifert test kits and it has shown Nitrites .5 - 1.0
<Hopefully sans livestock presence>
and Nitrates 5 - 10. Getting low on those test kits, I found a Hach Saltwater Master test kit direct from Hach for $58 which included 50 tests each of Ammonia, Nitrite, Nitrate and pH (what a steal I thought).
<...!>
Got the new tests yesterday and of course had to try them out. The Hach test kit shows undetectable amounts of Ammonia, Nitrite and Nitrate on the 20 g. Being puzzled, I did the same test with the Salifert kits which showed Nitrites around 1 and Nitrates around 10. So, I did the same testing with the QT tank. Same results, Hach undetectable, and Salifert show Nitrites 1 and Nitrates 10. Trying to get the bottom of it, I decided to test my pre-mixed saltwater which I use RODI water with a TDS of 1 and Bio-Sea Marinemix which I just mixed it last night. Hach shows Ammonia, Nitrite and Nitrate undetectable, and Salifert shows Ammonia 0, Nitrite 1 and Nitrate 5. So, is the pre-mixed salt water supposed to be 0 for Ammonia, Nitrite and Nitrate?
<Yes, though some will show nitrate and some do register some ammonia initially>
I assume it should be since there is no bioload. I just want to make sure my new test kit is the "bomb" before I return my livestock to the 20 g display. Do you think my tank is ready, or should I wait until Salifert shows I have 0 Nitrites (which could be never).
Michael Svehla
<I would "check the checker" here... take both kits to a dealer, have them test their water with them. I read the Salifert's as being off here. Hach is a MAJOR manufacturer of many other companies' reagents... Bob Fenner>

Seachem test kit, Unclear Instructions, Equipment - Go to the Man Himself  12/1/05
Hi,
I just started administering copper to my 30g quarantine tank for a velvet outbreak. It contains 3 blue reef Chromis, 1 firefish, 1 filament wrasse, and 1 Lubbock wrasse. I used Cupramine and followed the directions exactly. I also have a Seachem test kit, but it doesn't seem to be displaying any results, even with the reference solution. Its a bare bottom, with pvc for structure, no carbon, and a couple sponge filters. 
The test kit is brand new, but what is confusing me is it states to use the sample pipette for water to be tested, and fill to the base of the bulb, then repeat. This doesn't seem to be working, but there is a mark halfway down the pipette and I'm wondering if this is the fill indicator mark? The instructions do not give an exact volume for the test water (ex. in milliliters) and I was wondering if you know an exact volume for the amount of water to be tested? or if you know somewhere I can find out? Seachem's website has no information. 
<Brandon, I have forwarded a copy of your query to Sea Chem. As soon as I get a reply I will get back to you. James (Salty Dog)>
Thanks, Brandon 

Seachem test kit, Unclear Instructions - Go to the Man Himself, The Man Responds  12/1/05
<Brandon, I pasted my reply from Sea Chem below. Hope this helps you out. James (Salty Dog)>
From: Seachem Tech Support <support@seachem.com>
Subject: Re: Copper Test Kit
Date: Thu 12/01/05 11:44 AM
Dear James,
Please reply to him that the reference is there to assure him that the kit is working properly. Since the reference is not giving the expected results than that means the reagents have gone bad. There are many things that can effect reagents, such as extreme heat or cold. Since the kit is not working properly he can contact us with his address and we will mail him replacement reagents. The directions are correct that you fill the sample pipette to the base of the bulb twice. Also recommend not to add any more than the directed amount of Cupramine until he get the replacement reagents.
Best Regards, Seachem Tech Support
Seachem Laboratories, Inc. www.seachem.com 888-SEACHEM

Does His Water Has More Calcium Than A Quart of Milk?
Hello All,
<Hi there. Scott F. here!>
I'm here again with another learning project.
<All part of the fun!>
I'm wondering if you could help direct me in interpreting my SeaTest Calcium test kit results.
I just bought this kit today and promptly tested my water, carefully following the directions.
According to the test (I ran it twice to be sure) I'm running  at 1080 mg/1 Ca.
<Gosh- I certainly hope not...! LOL>
The test kit itself says it only tests 0 to 500 mg. So if your familiar with this kit, when you get to reagent 3 you add drops and swirl on each drop until the test water turns pure blue.
<Right..>
My test water started to change at drop 62 and became pure blue at drop 72, you now multiply 72 *15 =1080.
<Hmm...something is definitely amiss here! A dumb question, but are you sure that you rinsed the measuring tube in tank water before commencing the test? Did you fill Reagent #1 to the mark shown on the dropper in the kit? Another possibility-Did you get all of the contents of the granular reagent out when you performed step 3? Just some thoughts.>
If I understand all this, I'm very high on my Ca. Is this a bad thing?
<Well, excessively high calcium could be a big problem, but you'd probably notice a "snowstorm" in the tank, as there is only so much calcium that can stay in solution. Unless you have been adding a ton of calcium supplements in a (no nice way to put it) reckless manner, or your source water contains extremely high amounts of calcium to begin with, I'd say that the problem lies with the testing procedure, expired reagents, etc. Maybe you should take a sample to a dependable LFS for a calcium test to see if they get the same result. At least this will eliminate the possibility of ultra-high calcium levels if the test results in a "normal" reading. Also, you may want to contact Aquarium Systems regarding the problem you are having. They may offer a recommendation for correction, or some other remedy for this problem>
Tank is a 55g started November 16th 2002. Removed crushed coral substrate 1 week & 2 days ago and replaced with 4" DSB. (My wife suggested out that the new sand bed is probably the cause of the high Ca here). Could she be right AGAIN? :-)
<Well- "high" is a relative term. There is "high" (like 400-450 mg/l), and then there is HIGH (1080 mg/l)! Deep sand beds certainly help maintain high calcium levels, among other benefits-but the level that you are recording is really unusual...Try the suggestions that I made...hopefully, you'll get things straightened out!>
Thanks in advance for the help. Dave
<Thanks for stopping by, Dave- and Good Luck! Regards, Scott F>

Calcium Tests-Shaken Not Stirred???
Kind Sirs,
< No "sir" needed! Scott F. here today!>
I have a question regarding the Calcium test kit by Aquarium Systems. Guess to be quite honest do I blame the test kit or the tester???
<It's a good hobbyist test kit, IMO. Certainly not as accurate as a LaMotte or a Salifert, but I like it myself>
I thought I read that on the site, that although it's not one of the best, it is an inexpensive test kit to help monitor calcium levels.
<Yep>
It happened to be carried by my LFS. But testing for the past week (first time calcium tester) I haven't been able to get a reading below the 500 limit. The test never changes over to its "true blue" color. If I may go through the process. Step 1 small vile of tank water, seems easy enough, taken from the top of the tank to prevent hands from entering the tank. Reagent 1 to line indicated, again thought I could handle it, do shake reagent before filling dropper to mark line. Reagent 2, dated March 04, figure still good. Swirl to mix. Should this be stirred???
<Nope- just swirled>
Then adding drops of reagent 3. Directions indicate swirl after each drop?
<I'd swirl after each drop>
Usually  swirl after adding 5,problem???
<This might be>
Also should this be stirred???
<nope- I wouldn't stir>
A brief supplementation history:
Tank 30 gal, about 20 lbs of live rock, upon recommendations of LPS, when purchasing last few lbs of rock, Bought and used Kent calcium, Kent Strontium and Kent Essential Elements. Up until that point I never supplemented anything to the tank. (4 years). Found your site, learned about the ion problem of calcium chloride, strontium supplementation is not really required but still use the Essential Elements to add iodide to the tank (for cleaner shrimp), <I think that you'd do better to just make frequent (2x weekly) small water changes. If you are going to use additives, you need to test for them>
Added calcium, a capful every 4 days up until 2 weeks ago (for about 1 month total), I was going to finish the bottle, figured with water changes and only using calcium chloride about 3 to 4
months I wouldn't have an ion problem. (But I learned that I should test before supplementing so I stopped adding until I can get the test kit figured out.)
<Great move on your part- you will not regret doing it this way>
PH always test around 8.4, no variation between day and night, figure it's the new (closed) house situation that I read about. And alk is always around 3.4 meq. I think it's on the low side,
<Actually, that's a good reading, IMO>
only buffer added is Red Sea Buffer  that came with the test kit, added to Water change water (not to tank) after instant ocean salt added and aerated overnight.
<Good technique, aerating the water before use, particularly if you're using R/O>
Not sure if any other tank condition would affect the test. Water changes are 4 gal every two weeks. Also, does SeaChem Calcium have a shelf life?
<Yes it does- I'd consult them for specifics (see the link to them on our site>
LPS has a few small bottles, (it mostly carries Kent products), and from the dust covering looks like it's been there awhile. Figured I'd switch to SeaChem after using up the Kent Calcium. The only calcium requirements I have for my tank at the moment is for Coralline algae growth.
<Seachem calcium is Calcium gluconate, and this stuff will grow coralline like crazy, if used correctly. I'd use Seachem's test kit if using this product, by the way>
Coralline consists of  some purple and green growth (little) some bleaching but leaned that's from improper dosing. Think it's form lack of, not excessive.
<Lots of reasons for coralline declines>
The only other calcium test kit available from LPS would be Red Sea. Would it be worth purchasing and testing or should I look to purchase test kits online? I'd stick with the Sea Test for now, and switch to the Seachem if using their calcium product.
(would like to avoid if possible-tank spending monitored to easily)
Temp is a steady 78 degrees and salinity is 1.021.
<Sounds fine>
Thanks for your help, DaveK
<Well, Dave- sounds like you're on the right track...Just keep thinking about making your hobby as simple as possible. Unless you have very specific reasons, I'd avoid using lots of different additives. Remember, the adage that we both touched on "don't add something to the water unless you are going to test for it". In many cases (there are, of course, exceptions), simply executing regular water changes can provide all of the trace element replenishment that you will need to maintain a healthy system. If you keep things simple, you'll enjoy your hobby so much more, and will really be successful in the long run! Good luck! Regards, Scott F>

- Odd Test Results -
I've been monitoring pH with FasTest colorimetric kit and was happy that I was getting a very stable 8.2 (now trending close to 8.3 with installation of calcium reactor). However, I borrowed a Sentron Argus pH meter with ISFET (non-glass) probe and got readings very close to neutral. I've got fresh calibration buffer and did two-point calibrations about 50 million times and I still get a pH of 7.0 to 7.1 on the meter for my tank water. Used some good old litmus paper too and it was in agreement with something close to neutral rather than the FasTest result. I am new to this. Is there something special about reef aquarium salt water that renders inaccurate results with instruments not specifically designed for this use? <Nope.> Specific gravity is 1.024 and the water tastes like sea water so there really is salt in it. Given that, I find it hard to believe the neutral readings and figure I should trust the FasTest result. What do you think? <Actually, I'd trust the electronic device more so... I've never been a fan of colorimetric kits, not that I'm color blind but I have an awful time discerning between ten shades of purple, so I prefer and use a digital meter. I'd consider running a water sample down to the local fish store to see if their results are similar. How about the life in the tank? I'd imagine that at a pH of 7.0 you'd have a hard time keeping anything alive... that might tilt your test results in one direction or the other.
Cheers, J -- >

-Different readings from different test kits-
Hi Crew, <Hello, Kevin here>
I am in the process of setting up my first marine tank. I am doing it  humanely. <Hurray!> On the first real cycle of the ammonia it has come down to 0 -.50. Nitrites  at this point are 5. My dilemma is that one test kit (Saltwater Master by  Aquarium Pharmaceuticals) is showing the ammonia at .50. The other kit (Marine  Master Saltwater Test Center by Marine Enterprises) is showing the ammonia  completely cleared. I am new at this and I sometimes feel overwhelmed, so your  insight would be very important.
<Aquarium Pharm's marine test kits are very unreliable, I've seen way too many people have false negatives when something bad was going on. I had little luck finding a vendor that sold the other kit, but if reading Marine Enterprise's site is any indicator, this one isn't too reliable either. The cheapest line of kits that I feel confident using on my own aquarium is the Fastest/SeaTest line mfg by Aquarium Systems. Salifert and LaMotte are higher end kits that will work wonderfully as well. I'd suggest testing again on any of these recommended brands. Good luck! -Kevin>
Thanks in advance, Tom

Interpretation Of Iodine Test Results...
Howdy.
<Hi there- Scott F. here today>
Dosing with Lugol's and had been using Salifert I2 test kit that is based on pink color of supernatant. That test never produced detectable iodine so bought new kit. New kit is much different (simpler, better?) and breaks out iodide, iodate, iodine. Instructions say that formation of precipitate with iodide test means concentration is greater than .2ppm. What is not clear to me is whether or not they mean if precipitate forms at 2-minute mark or if it forms at all. At 2 minutes, yellow color matches .04-.06ppm color chip. At 3 minutes, dark ppt forms. Are you familiar with this kit?
<I have used it in the past, but I do not have any recent experience with it. You bring up a good point...Not sure if the precipitate forms at the two or three minute mark...I would not assume anything, either.>
Does formation of ppt at 3 minutes mean that I need to back off dose? Salifert Web site is under construction and LFS is no help, Thanks, George.
<Well, George, what I might try is the "end run" to get hold of someone at Salifert that may have the knowledge of the workings of this kit...I'd talk to the LFS and find out what wholesaler they get the kits from, and-in turn, who supplies the wholesaler (hopefully, Salifert or their domestic sales reps). Yep- it has all the makings of a wild goose chase, but it may help you locate someone at the company who can help. In fact- here's an open call to any WWM reader that might know the answer to this question, as well....Regards, Scott F>

Nessler's Reagent Strikes Again!
Greetings! 
Want to say thanks again for your web site and all the great information you have there. 
<If you loved the planet, the hobby as we do... you would/will do the same> 
Here is my problem. I have a 55gal marine setup and up to this past week, I was using bottled water from the store because my tap had unacceptable levels of copper in it (planning to build a mini-reef eventually). Since I was worried about chlorine & chloramines, I was adding Amquel+ by Kordon. Now when I tested my water at home, I was using a test kit by Tetra and I was coming up with 0 nitrites, 0 nitrites and 0 ammonia. When I bring a water sample into my LFS (local fish store.....I'm still learning the abbrev of your site) they always got readings of ammonia between 0.25 and 0.5 ppm even though I tested the water not even an hour earlier and got 0 ammonia. Everything else they tested always came up optimal (0 nitrate, 0 nitrite, SG 1.023, pH 8.3).  Water change after water change, still was getting the same results (my recycle guy must hate me because of all the empty water jugs in the bin). The whole time I was using the Amquel+ on the new water. I took a closer reading of the Amquel+ label and it says that you should not use an ammonia kit based on Nessler reagents. I found out that they are using the test kit Dry-Tab by Aquarium Pharmaceuticals.  Having a minor in Chemistry (it was a while ago though) I have an idea of what a Nessler reagent is. I am wondering if that is what Dry-Tab is using and Tetra is not (neither says anything about what they use on the box). Could this explain why they always get high ammonia readings while I am getting none? 
<Yes... the conditioner is rendering the false negative result> 
If that is the problem, it will be solved soon because I am now using RO/DI water so I no longer have to lug gallon after gallon home from the store. 
<Good move> 
My RO/DI water is also testing at less than 5 TDS so I do not see a need to continue the Amquel+ any more....unless you think I should continue to use it. 
Thanks again!  - Ray 
<I would discontinue its use. Bob Fenner>

Nitrate testing!
Dear WWM Crew!
   Thanks for all your help in the past. I was able to cure the ich, but lost fish to a fungal infection... and returned the survivors to the LFS. Anyway, getting to the point: A few weeks ago I complained that my Red Sea Nitrate test kit always read Zero PPM for nitrate -my 72G tank has a wet dry and DSB and has been running for 7 months with  plenty of crabs and shrimp -It had fish for 2 weeks only before they were moved to a QT. Based on your advice I purchased a SeaTest kit. It reads Zero too!
I'd believe this number, except for one thing -I could never get the 2nd reagent to dissolve completely! Is that why I'm getting zero PPM even with the low range kit!
Narayan
<Yes, likely so... Sounds to me like these test kits' reagents are "old"... I would return them to your dealer for replacement. Bob Fenner>

Test kits and bosses going bad - 11/28/2005
Happy Holidays!  I work for a LFS. My boss is a great guy, very smart and loves his work.  However, he and I have a standing argument.
<That's what bosses are for. Remember to let them win sometimes ;)>
He refuses to acknowledge that test kits go bad. The tests that we perform on our customers' water is performed with some kits going back to expiring in '97. I have taken chemistry in college. I was taught that reagents go bad. I have a problem with testing my customers water and not being 100 percent confident about the results.
<Absolutely. I applaud you for being so responsible>
Can anyone settle this argument once and for all? What's the longest a test kit can go?
<Certainly. As long as the expiry date on the box :D. If not stored correctly (sealed, cool, dry, dark place), they may not even make it that long -- as an example, some reagents in nitrate tests are photosensitive and exposure to light will denature them over time.>
Thanks so much.
<Thank you for writing... John>

Test kits
Bob,
Thank you for your recent help with the Dottyback & royal Gramma. I have returned the Dottyback and replaced it with a cleaner shrimp (Lysmata amboinensis)
<A much happier arrangement no doubt>
I have another question for you. I bought a Red Sea Fish Pharm Saltwater Test kit (Ammonia, Nitrite, Nitrate, Ph, & Alkalinity) last fall before setting up my 55 gal. saltwater tank. I consistently get the same readings when I do the Nitrate test. (2.5 ppm using the liquid reagents and 10 ppm using the dry reagent) I don't think that can be right. 
<Uh, no...>
They should either be climbing or dropping off. I doubt that I have enough live rock for them to really drop off.
<Would definitely "test the testers" here... sounds like you have bunk reagents... take them back to the dealer, and they can/will return them back up the line...>
My 2 1/2 month old set-up is as follows:
55 gal.
UG filter plenum
40 lbs. Aragonite
4 lbs. Fiji live rock (Working on slowly)
Lee's 16 inch Counter Current skimmer
Whisper 5 Power Filter
Penguin 660 Power head
twin tube shop light hung over glass tops.
200 watt Hagen Tronic heater
Livestock:
2 ocellaris/Percula clowns (I think they're ocellaris. Dealer said they were Percula.)
Royal Gramma
Common Cleaner Shrimp
6 turbo snails
6 blue-legged hermit crabs
I suspect that the test kits are either old or just inaccurate. I haven't done a water change in a month or so. I had to throw out a big batch of water, then had the Dottyback in my hospital tank which I was using for mixing water. I now have a 5 gallon pail that I am using for mixing water.
Because of the time since a water change, I really think that nitrates should be rising.
<You are correct>
Do you concur that the nitrates should either rise or fall? If so, would you suspect the test kit's age or quality?
<Both>
My main question is: Do you have a recommendation for test kits?
<Salifert, Hach, LaMotte...>
I have gotten varying advice. One fish store recommended Tetra's test, another recommended Hagen's. Aquarium Systems SeaTest and FasTest seem to have a wide following but the store recommending Hagen said he quit carrying the FasTest and SeaTest kits because he got a lot of complaints about inaccuracy. In your book, CMA, you picture the SeaTest and FasTest kits.
<These are okay... made by Hach for AS...>
Somewhere I read (I thought it was your book, but couldn't find it again.)
that test kits that have transparent color guides are better. I like the look of the Aquarium Systems tests, they look like they would be easy to read results. Are there any other test kits that have transparent color guides rather than cards? What about the test strips that you just dip in the water; are they any good?
<Yes, accurate and precise enough for aquarium use...>
Thanks for all your assistance. Jeff Schulz
<Be chatting my friend. Bob Fenner>

Calcium testing
Hi Bob.
I thought you might like to hear of a problem I've come across with using the Seatest's Calcium test. I was concerned with a low calcium reading so I thought I would repeat the test to ensure accuracy. During five tests all conducted within half an hour, I got some strange readings. One test never did change color from pink to blue, suggesting a calcium level over 700. The other four tests ranged from a low of 375 to a high of 420. Is this sort of variation normal when testing calcium?
<No... decidedly not>
Should I average the readings?
<I wouldn't...>
Is there a more reliable brand?
<Yes... more accurate (measuring what's there), precise (rendering the same results)... like Salifert, Hach, LaMotte...>
I've also heard that there are TDS meters that test calcium accurately for a couple of hundred bucks. Are there any you would recommend?
<Hmm... no... as far as I know total dissolved solids meters only approximate calcium concentration measures...>
Thanks for your help, your site is very informative and the advice you offer is priceless.
Dave.
<Hmm, must be why it doesn't pay! Bob Fenner>

Amquel/Test Kit questions
Hiya Bob.
Thanks for all of your assistance. Your help is invaluable.
I happened to read on the bottle that Amquel can't be used with Nessler reagent test kits. How does one know if a test kit has Nessler reagents?
<A constituent here is Nitric Acid... yellow readings as indicators... and your test kit will likely contain warnings re nitric...>
If one uses test kits with Nessler reagents, and has also been using Amquel to treat tap water in both marine and saltwater tanks, how long does that stuff, if used over a period of time, remain in the water to affect test results?
<Hours to a few days>
Happily, I've purchased a KM RO/DI/Hi-S 60 gpd unit which should be here in a few days, so I won't have to use Amquel or the like anymore. Yea! 
<Yes, a much better route>
My tanks grow brown diatom algae in bumper crops, so I am quite excited to be getting this unit. We did check Home Depot and a number of online retailers of various home water treatment systems, and for the output and stages this particular KM unit offers, nothing came close price-wise.
<Ah, thanks for this input>
Another thing that I'm wondering (since I have you as my captive audience *grin*) is about a hitchhiker that came along on a lovely piece of rock that I ordered sight unseen from FFE. It was supposed to be a 3 to 5" mass of tea cup Caulerpa, but my goodness, it has 5 or 6 different varieties of plants as well as a dozen or more tiny feather dusters and some kind of little tentacled patch with circles on the end of its tentacles! 
<Yes... these "items" don't come "punched out of a machine"... Perhaps a zoanthid of some sort...>
What I'm concerned about, though, is something black, flat, and slimy, about 1" by 1" in size or so. I didn't know what to do with it (kinda scared of it, actually) so I left it there.
<Good... likely a sponge species... and will pass with no problem...>
When I looked at it yesterday, it appeared to have a bright yellow or orange circle of color on it, which wasn't there last night when I looked at it again (it had moved a bit further into a crevice in the rock).
I don't want to handle the rock too much because of all the little feather dusters, but I'm fascinated by that thing. Any idea of what it is? Sorry I can't send you a digitized pic (yet -- but give me a week). Actually, I went to go look at it again and it's no longer on that rock, so I sure hope whatever it is isn't bad!
Have a blessed Easter!
Sherri
<Thank you my friend. And no worries re this organism. Bob Fenner>

pH levels
Mr. Fenner,
<Hi there>
I have my 90 gallon system up and running for a month now with about 90 lbs of live rock, a bunch of turbo snails, 2 cleaner shrimp, hermit crabs, 4 Emerald green crabs, 2 Percula Clowns and a Royal Gramma. Ammonia is zero, Nitrite is zero, and Nitrate is between 5&10. My PH Level a week ago was 8.1 to 8.3, but today it is a purplish colours that I don't even see on the green to blue scale. 
<Bizarre>
I am not sure what to make of this PH level. Is this too high or too low?? Everything seems to be doing just fine.
John Kummer
<Think something is amiss with the kit. Do "check the checker" here... test a freshwater (tap) sample, some newly made-up seawater... and get on down to a LFS (local fish store) and have them check your kit against one of theirs. Bob Fenner>

NO3 Test Kit and PH Buffer
Hi Bob,
I have a reef tank of about 180 gal and have been using Tetra's test kit for NO3 for some time. Recently I bought an API NO3 test kit and discovered a big difference in the test results. Very roughly, the Tetra test kit gives a result that is 4 to 5 times higher than the API one. Bob, are you aware of such a difference and why? How should I interpret these readings?
<Mmm, there shouldn't be such a large difference as this... Do check for me if the "units of measure" are the same... "Nitrogen as Nitrate", Nitrate in ppm, what have you... and take a sample of your water to a local fish store and have them check your NO3 level... it may be that the reagents of one kit have "gone bad">
I have been using Ca Reactor for my reef tank since 2 months ago. Over the past 2 months, PH dropped from 8.5 to 8.1. It has stayed at this level (8.1) for the past 2 or 3 weeks. My KH is about 10 or 11. I am wondering whether I have added too much CO2 and is trying to reduce the amount. 
<Hmm... the pH and KH levels are fine... you might experiment with letting the effluent pH (from the calcium reactor) be a couple of tenths of a pH point higher... and see what this results in pH and alkalinity wise over a few days...>
My question is: would the use of Ca Reactor, with the right amount of CO2, be able to maintain a stable PH of around 8.2.
<... yes... given one more principal factor... the type, amount of "feeder stock" that you're melting in the reactor>
I also understand baking soda can be used to maintain the PH, but not sure whether I should go for this option together with the use of Ca Reactor. Your advise is much appreciated.
Regards,
David
<Baking soda, sodium bicarbonate won't raise the pH in settings, levels of use in a situation like yours... you could add some calcium hydroxide solution (Kalkwasser), calcium chloride... but I wouldn't, am not concerned... a pH of 8.1 is fine. Bob Fenner>

Re: NO3 Test Kit and pH Buffer
Hi Bob,
Thanks again for your reply, which is very helpful for my understanding about pH control. Regarding the NO3 test kits, may be I have confused you with the names and numbers. To my understanding, both Tetra and API say they measure the same thing, namely, NO3-. 
<Both do have test kits with this measure>
One would expect both reagents to give same results.
<Yes>
As API states very clearly that it is not measuring N-NO3, therefore if anything, Tetra would give a reading 4 times lower than API. But in my case, I got an opposite result - Tetra is 4 times higher. 
<Seems that one of their reagents are shot>
A friend of mine told me that he had a similar problem with the Tetra test kit and somehow got to understand that API may be measuring free NO3 ions whereas Tetra may be measuring both NO3 ions and any Nitrate compounds in the solution, and that only free ions are our concerns. I have no way to know whether this is the case.
<Mmm, a few ways... the easiest, most straightforward to contact Tetra for technical help, customer service: http://www.tetra-fish.com/ and ask for help in deciphering their test kit results. Bob Fenner>
Regards,
David

Re: NO3 Test Kit and pH Buffer
Thanks Bob for your very prompt reply. Both the Tetra and API test kits say they measure nitrate (NO3-) in ppm or mg/l.
<Yes... these are equivalents>
In particular, API says it measures total nitrate which may be 4.4 times higher than some other kits that only measure Nitrogen as Nitrate. 
<This is so>
But in my case, I got higher results from Tetra which does not seem to make sense to me. 
<Simple stoichiometrics my friend... you can/could do the math... nitrogen as a percent of nitrate... three oxygens to one N...>
I had in fact tried 2 different samples from different sources, one from my tank and one from tape water. The Tetra gave a reading of 20 ppm for tape water and 40 ppm for my tank. The API gave a reading of 4 ppm and 8 ppm respectively.
<I believe both...>
On the pH problem, I am not concerned about a 8.1 pH. However, since I noticed the drop in pH, I was anticipating a further drop and therefore planning ahead of what to do in case it drops below 8.0. 
<Mmm... good to anticipate, plan... but you may never experience this "drop" due to sufficient alkaline reserve at or about the 8 or so point>
I read somewhere in your website about an opinion that if nothing is done to maintain your tank's pH, you would expect the pH to drop by 0.1 every week and adding baking soda is a solution to this pH depletion problem. 
<One solution, yes... as are water changes, ready-soluble sources of carbonate, bicarbonate in a system...>
Just to make sure I get it right, is it true that the use of ca reactor, in a proper manner, should by itself alone, take care of the pH depletion problem? 
<Yes... as well as biomineral, alkaline content, carbon dioxide availability...>
And if one has to raise the pH level, calcium hydroxide (or calcium chloride) should be added, rather than baking soda?
<At some point, yes... In most systems, the addition of sodium bicarbonate will not elevate pH beyond about 7.8... try it yourself...dissolve some in freshwater or some freshly made and pH depressed (maybe with the simple organic acid acetic, or vinegar, CH3COOH) seawater...>
Am I also correct to say that adding baking soda will maintain or increase the buffer but not the pH?
<... Mmm, yes... the baking soda will only increase the pH to a point... but will continue to add (to saturation) to alkaline reserve... at that point>
I am somewhat confused about a high pH and a high buffer. Is it correct to say the two have no direct relationship, but a high buffer will help to maintain a constant pH (whatever it is, high or low)? 
<Yes... you do understand>
Once again, I thank you for your help, this is my third time receiving advices from you.
Regards,
David
<We will keep going over these phenomena, pH and alkalinity, till you feel you understand them. One is a "point", the other "resistance" to change in that point. Bob Fenner>

Tunicates/Sea Squirts and the Salifert Phosphate Test Kit
Bob, Once again I need your knowledge regarding a couple of questions for my 100 gallon saltwater tank: (1) I noticed at my LFS that they had some of the large yellow and blue tunicates available (like the ones pictured in your excellent book, Conscientious.. p. 336). I am interested in adding these to my tank, but was not sure what their requirements are, i.e. light, current, compatibility, etc. My lighting is 4 x 96W 48 inch Power Compacts; two 10,000k super daylights and two 9600 actinics. These are on for 12 hr/10,000K and 14hr./Actinics. Fish are yellow tang, four cardinals, lawnmower goby, one damsel and one Pseudochromis. I also have several hard and soft corals, as well as two Tridacna derasa and one T. squamosa. 
<Please see/read here: http://www.wetwebmedia.com/ascidians.htm> (2) Do you know of anyway to verify that the reagents in the Salifert's Phosphate test kit are still good? 
<Yes... by making a solution of known or some given concentration having phosphates (you can even use a bit of "Coca Cola" tm for the phosphoric acid contained therein to give you a yes/no answer>
I tested my tanks water and the reading was 0.0, but I also tested my tap water and my outside ponds water and these results were also around 0 ppm. 
<They may actually be zero>
This has me concerned that the test kit reagents are no longer viable. As I ordered it from my LFS, they did not know the age of the kit as they had none on their shelf and ordered this one for me. If you know of any solution that would act a good control or standard, please let me know. I would not be concerned about the phosphate level, but I have had some algae in the last 4 months grow on a couple of my live rocks and areas of the sand bed and I have to clean the green algae off the front glass twice a week (which the Tang loves to eat as I clean it off!). My protein skimmer, Aqua C 150, requires cleaning every 4 days. Nitrates when tested measure 0.0 ppm, pH is 8.3, and alk 3.43. I have a Korallin calcium reactor that now uses CaribSea ARM for the media and the effluent is alk 45 dKH/540 ppm CA; I was using SuperCalc Gold before switching to ARM two weeks ago, as I was concerned about phosphate from the Super Calc Gold might be the causing the algae growth.
<Maybe>
Thank you again for your advice in the past. Other then these two questions my tank has done very well, with water very clear and all life growing and active, due to the information you have supplied on your website.
<Ahh, a pleasure to be of service. Bob Fenner>
Regards, Kevin

I think I am in trouble
Hi bob,
Me again the Turk :-)
I had all fine until last week , when my dad got to be hospitalized and had no time to get RO water and I put bottled drinking water. Since then I all types of algae problem. First brown/red hair all over. Cleaned that now I have blue green.
I checked Monday and had low GH, KH, CAL . So I added buffers and cal.
Now I have following-
temp- 26.5 C
gravity- 1.0255
ph - 8.5
kH- 260 mg/l
gH - 1400+ mg/l wow I don't think this is good
calcium 850 +
PO - 0 nada
<What? Something/s are way off here... Please, first have your water tested by a store, other hobbyists test kits... the general hardness and calcium are likely not what you state.>
I still have the algae unfortunately but all other creatures seems happy.
I am looking forward to your comments
thanks
<Do have the kits checked against others. Bob Fenner>

Salifert Test Kits
Mr. Bob,
<Steven Pro this evening.>
I know how you like Salifert test kits,
<I do, too.>
but they do not have expiration dates on them. Do you think they expire anyway?
<All kits and their reagents will go bad in time.>
I heard that all kits (including Salifert) will expire in about a year, is this accurate?
<I do not know if all reagents would go bad in one year, but I would guess that they would all remain reasonably accurate for one year. You may want to contact customer support. All Salifert kits come with a batch number which may relate to expiration. -Steven Pro>

ORP accuracy/calibration 8/15/04
Hello,
<Cheers>
I recently purchased a pinpoint ORP monitor for my 110g reef tank.  I placed the probe in my sump about 4-5" away from my pH monitor as per the instructions.  The instructions also stated it my take 24-36 for a true reading so I waited a couple days.  
<this is true... very good>
I was a bit shocked yesterday when I noticed the monitor said 586mV and this morning it is a little bit above 600mV.  I'm very confused as to how my levels are so high, I do not use Ozone.
<even with ozone, this would be a surprisingly high measurement... the unit is clearly misreading here. 350-425mv is a safe range. Do recalibrate the unit and perhaps give is a few more days to break in. Contact the mfg or your LFS for support if you didn't mail order it (one of the many benefits to supporting your LFS)>
Thanks for your time. Chris
<best regards, Anthony>

Calcium test kit accuracy 10/03/04
I have read several of the FAQ's on calcium, and still have a question.  I have a 125g that I started Sept. 1.  I added 125lbs of un-cured LR on Sept. 11.  Euro-reef skimmer (in sump), fluidized bed.  A lot of my LR has a white coating on it - like a crust.  
<assuming you have adequate water flow for curing rock (20X+ turnover of the tank?), this may simply be decay from hard curing rock>
My calcium readings are off the chart (>500ppm).  
<this seems very highly unlikely after even a few hours (without precipitating). Much more likely that you are getting a misreading from your test kit. Even new kits can give false readings. Do take a water sample to a friend or the LFS for a test of CA on a different type or brand of test kit>
I read about the possibility of a "snow storm" and it is scaring  crap out of me.  
<no worries... you would have to be/have been adding obscene amounts of Ca>
I changed 19gallons of water today, using DI water -
<yikes! now that is dangerous. Never, ever use/add raw DI or RO water. Always aerate for 12+ hours then buffer 2+ hours in advance of salting or using for evap water>
calcium is still off the chart.  
<I see... all the more reason after using demineralized water to believe that this is a misreading on your test kit>
I have only added Bi-onics only once. Today I just added the Alkalinity part (part 1) in the hopes of driving the calcium down.
What to do?
<I'm as certain as I can be from here that you have a bogus test reading... test again my friend. Anthony>

SeaTest calcium test
Well after using this test kit I am thoroughly confused. I have finally after 2 years decided to test my calcium level. I have never dosed Kalk or any other calcium supplement other than water change which I did about 5 days ago (4 gallons). My 55 has varius softies and mushrooms, I run 220 watts VHO 1 white 1 blue. Now for the question after getting a recommendation I bought a SeaTest calcium test kit online. I read through the instructions and think I have followed them verbatim. After I took tank sample and added 1st reagent my sample turned extremely cloudy, then with the addition of the packet my sample turned purple, the kit says true blue color change so I continued to add drops of #3 until I had reached 32 drops. The instructions never said anything about the change to purple to begin with is this normal?
<Not normal as far as I recall. I would contact the folks at Aquarium Systems (http://www.aquariumsystems.com/frames1.htm) and ask technical help there for information re your reagents. Bob Fenner>

Re: SeaTest calcium test
I contacted Aquarium Systems which told me to cut my sampling of saltwater in half and use regular water for the other half.
<Huh? What is the rationale, if they offered such, for this? Folks who use this kit... use it on/with seawater...>
The only other thing it changes is the last step which you have to double to get things straight.
Thought you may want to add this in case someone else can't easily see a change from purple to blue this makes it violet to blue and easy to tell the difference. Thanks
<Thank you for the follow-up... Methinks the folks at Aquarium Systems have some product re-working to do. Bob Fenner>

Calcium test kits?
Dear WWM crew,
  Was curious if anyone there had experience with this brand of kit.
According to the dating on the package the reagents are within their shelf life, but when I add the first step with my saltwater I get no color change to blue? << And you are sure you should?  Hmmm, I doubt it has gone bad. >> Any help or a recommendation for a different kit would be much
appreciated! << I don't think you can go wrong with a RedSea test kit. >>
Thanks In Advance
<<  Blundell  >>

Test Kit Discrepancy 12/16/04
Hey folks, I'll cut right to the point (sort of). I have a LaMotte Ca test kit. I have two Salifert Ca test kits. The LaMotte indicates something like >800 ppm. The Salifert shows less than 200 ppm. Now I just realized today, after months of using the LaMotte kit that it measures CaCO3 (calcium carbonate) which isn't the same as just free ion Ca (right?). <Well, I will be totally direct... maybe.  Sort of.  Is your LaMotte test kit a harness kit or calcium kit?  It sounds like it is a harness kit which would measure all hardness metals (Ca and Mg mostly) and give you a result AS IF all of the hardness was from calcium.  I would trust the Salifert, especially since they agree with each other.  It is also possible that one of the reagents is bad.>
Ok. I previously bought a Salifert Ca test kit when I started getting the really high LaMotte kit readings. This (the Salifert) should just measure Ca ion concentration, right? I thought the Salifert was wrong when I started getting readings of 190 ppm over the past couple of weeks. So, I bought another Salifert test kit. I got the same readings as the first Salifert, which is OK and sort of a relief for me to know that at least the kits are accurate with respect to each other. <Salifert test kits are know for good quality, but also for subtle, hard to see color changes.  I can usually see the color change best in bright natural sunlight and often get verification from my wife.>
I started to throw out the LaMotte Kit when I read that it measures CaCO3 not Ca, which would make the readings seem substantially higher, right??? So maybe the LaMotte readings of 800+ are actually OK since it's not just measuring Ca by itself.
<The kit is probably fine, but it is not measuring what you expect it to.>
Is there a formula to determine the amount of Ca (in ppm) from CaCO3 reading or a table to cross reference the readings? Should the CaCO3 be around 900 or so? Is my thinking outta whack? BTW, my alkalinity is 12 dKH (Salifert test). Thanks, Randy <There may be, but you would probably have to measure the Mg and subtract which would probably defeat the purpose.  Best Regards.  AdamC.>