falling alkalinity

[cich1]

for the last month i have been slowly trying to get MG./ALK.CA. up to proper levels and have been pretty happy with the results so far.
when i started on 1/1/05 ca. was 350ppm alk. was 8.3 dkh and mg. was 1050ppm. i started alternating dosing epsom salts for mg. and pickling lyme for ca./alk and everything was proceeding as i expected it to, as of 1/23/05 ca. was up to 400ppm, alk. had dropped to 7.4 dkh and mg. had risen to 1330ppm.
this week when i tested i had 400ppm ca., 1350ppm mg. and alk had dropped to 3.2dkh, i thought maybe i had tested wrong so i retested alk. and came up with the same reading, this is using a salifert test kit so i retested using a Fastest kit i have and came up with 4.2 dkh.
i tend to trust the salifert test more than the fastest kit but either way alk. has dropped substantionaly in one week and i was wondering if anyone knows what may be causing it?
btw it don't know if this is relavant but my ph is always between 8.2-8.4 but with my alk. all over the place i'm not sure why ph stays so stable

Not real sure why the alk would have dropped like that and not have effected the ca & mag... are you using the kalk to bring up your levels?? or are you using a buffer and ca additives??

[REEFTEC]

this could very well happen for a few differenet rasons if you are usingthe stuff in the right ratios & your ph stable your alk droping that much means something is trying tolower the ph & usin yourbuffer reserve to your extent though i don't know cause i never used epsom or p. lyme i started using a cal. ractor a week after introducing my first corals inverts,etc
with a cal ractor this is what you doing
CA CO3(arg media)+CO2+H2O----->ca+2 + 2(HCO3-)
which is media +co2 injection in ractor will give youcalcium &bicabonate which is the buffering element or alk in your system
now a lot of the additives are pure ca for your system & donot raise yor alk unless you use the 2 part
i donot know your situation your tank size or why it happened however @ this point with that low of alk what i recomand instead of adding stuff to your tank to bring alk up that much ,makes sence to do a larger volume water change witha choice of salt that gives you high alk &ca (reef crystal is what i use, is good)
let us know what was the reason

[cich1]

Not real sure why the alk would have dropped like that and not have effected the ca & mag... are you using the kalk to bring up your levels?? or are you using a buffer and ca additives??
yes Travis i've been dripping kalk everyother morning for the last 2 weeks and quit using the 2 part additives all together.
i was quite suprised to see my alk drop like it did and was curious what would have caused it.
i got some baking soda lastnight and mixed 2 tsp. with some ro water and dripped it in and i have my morning kalk dripping right now so i'll retest again alttle later

I would continue to use the baking soda until your alk is where you want it. Use something like turbo calcium to bring the calcium up to where you want it (it will probably drop when you raise the alk) and then use the kalk to maintain the levels. Kalk isn't the best at raising levels... use backing soda and turbo calcium or B-Ionic to make adjustments when needed.

[cich1]

I do have some Kent Marine liquid calcium but none of the lfs have alk or mg buffers, after dosing some baking soda my alks back up to 8.4 dkh, just out of curiosity i tested some fresh sw i had mixed and it was 7.0 dkh which i found interesting because last time i tested it i came up over 9.0 dkh

[MikeS]

Ok....lets start at the beginning? Whats your SG, cich?

1350 is plenty of Mg....actually a bit high, esp. if your SG is lower than 1.026. Mg plays a part in the whole balance, so adjusting it can affect the levels of the others, which I'm betting is part of the reason you saw the drop in alk., even using kalkwasser, which is already balanced between Ca and alk. 400 ppm Ca. is also good (depending on your SG)....so concentrate on your alk....

Your pH is in a good range, so I agree with Travis, use baking soda...you'll want to shoot for around 2.0 meq/L @ 400ppm Ca....

Once you get a good balance, then you can maintain those levels with kalkwasser.

Mike

[cich1]

Mike my SG was 1.026 at the time i tested however i usally try to maintain it at 1.025.
when i decided it was time to get my alk. and ca. up to where it should be my mg. was 1050 ppm so i started dosing epson salts because i couldn't get an mg. supplement locally, once i reached 1350 ppm i discontinued dosing at that time i started dosing kalk and alternated with some Kent Marine liquid calcium but didn't add anything to boost alk as it was already elevated, but looking back through my notes i see that alk. has been dropping all along but it wasn't until this week that there was a rapid drop that concerned me. heres a running log of my numbers over the last month.

1/1/05 mg. 1050 ppm, ca. 350 ppm, alk 2.97 meg/l

1/8/05 mg. 1140ppm, ca 350ppm alk. 2.57 meg/l

1/15/05 mg. 1230 ppm ca. 380ppm, alk. 2.63 meg/l

1/23/05 mg. 1330 ppm ca. 400ppm, alk. 2.63 meg/l

1/29/05 mg. 1350 ppm ca. 400ppm, alk. 1.14 meg/l

i added 2 tsp. baking soda disolved in ro/di water 1/29 and now my alk is back up to 2.97

[MikeS]

ok, looks good....

at 1.025sg, good levels to shoot for would be 1240ppm Mg. (just let your current level drop on its own, then maintain it around 1240 give or take), 410ppm Ca, and around 2.5 meq/L alkalinity. Once you have a good Ca/alk balance, I'd recommend maintaining with kalk, as it is already naturaly balanced...

Mike

[cich1]

sounds like a plan, i'm going to dose 1 liter of kalk everyother day for the next week and see if i'm going up or down or maintaining and then i'll adjust the amout accordingly until i find the correct amount, at least now i'm in the ballpark

[MoonSoft]

First off again I don’t claim to be an expert but I like to experiment and this is what I have found about Alk problems.

Most aquarists like to try and shave off the cost of additive, AS DO I!!! Who would like to pay the high dollars for supplements? When dosing to increase alkalinity remember that you have two parts to alk I use the Reef Status tests from Seachem they are not too expensive but well worth the price get the calcium test kit.

First part of Alkalinity is Carbonic alkalinity this is the "baking soda" portion that is readily utilized by reef creatures.

Second part is Borate Alkalinity, there are also some other minor elements that make up infinitesimal portion of total alkalinity.

Understand that raising JUST the carbonate alkalinity you are essentially putting in more GLUE portion that corals use to build skeletons, borate plays a somewhat misunderstood role in alkalinity, but it stays in solution LONGER!!!!

Dosing with "baking soda" is not recommended for the simple fact that there is no way to know exactly how much your adding to the system, unless you have some formula of dosing this EXACTLY I don’t recommend it because of the danger of the "snowstorm" of precipitate of calcium and magnesium that can take place, thus destroying the ionic balance of the system, if you are trying to increase alk it is recommended that you test for borate levels, as well as carbonate levels once you reach about 4.5mg/l of carbonate you will initiate precipitation, you can exceed 4.5mg/l by also dosing borate this is done over time with a supplement that contains borate.

Since Borate is not used as much as carbonate for calcification, once you build up about a 1.2mg/l of borate you will be able to have about 4-4.5mg/l of carbonate the change will not swing so much because the borate will help neutralize the acids the carbonate will be used for calcification instead of carbonate doing BOTH jobs then you can attain a alk of about 5-5.5mg/l It is recommended to keep higher levels of alk to prevent PH shift and also to keep your SPS and other hard corals in supply of glue for the calcification process

"Alkalinity is often confused with carbonate hardness since both participate in acid neutralization and test kits may express both in either of the three units. However, carbonate hardness is technically a measure of only the carbonate species in equilibria whereas alkalinity measures the total acid binding ions present which may include sulfates, hydroxides, borates and others in addition to carbonates. In natural seawater, though, carbonates make up 96% of the alkalinity so equating alkalinity with carbonate hardness isn't too far off." Thomas Hynes www.saltaquarium.about.com

See the missing link?? It’s not too far off but it's hardly perfect.

Given those examples I would go ahead and start finding the source of the acids in your system, making sure feeding is not to excessive or old filters are cleaned or replaced. Acid buildup can also be staved with additions of oolite sand even at less than 1/2" this still remains effective. Feeding is the main cause of acid build-up, myself I feed about every other day sometimes more during my high temp cycle to simulate spring and summer.

[MoonSoft]

I might also add that your SG is VERY important as well as temp the higher the temp the faster acids can build up and the more nutrients remain in solution... imagine heating water.. it allows you to dissolve more sugar or salt, both of which are IONIC..... just like your aquarium system.

[MikeS]

Dosing with "baking soda" is not recommended

Not recommended by who? The use of baking soda to add carbonate alkalinity to the reef tank is a pretty common practice, accepted and endorsed by many leading minds in the hobby...

the simple fact that there is no way to know exactly how much your adding to the system,.

There is plenty of information out there on dosing amounts when it comes to baking soda...Chemistry calculators like this one are common....

http://home.comcast.net/~jdieck1/chem_calc3.html

....it will determine the amount of baking soda (or other products for that matter) you need based on your tank water volume, existing alkalinity, and desired alkalinity...I have tested the results of the recommended dosages in my reef and found them to be accurate.

There are also premix additive recipies using baking soda out there from reputable reefkeepers, with mix and dosing instructions...

http://www.advancedaquarist.com/issues/april2004/chem.htm


unless you have some formula of dosing this EXACTLY I don’t recommend it because of the danger of the "snowstorm" of precipitate of calcium and magnesium that can take place, thus destroying the ionic balance of the system,.

Sure, but the same can be said about any alkalinity suppliment on the market. If you overdo it, you can have problems. The key with any of these is to ease into it...I'll use Kent Pro-Buffer dKH for example. The dosing instructions on the bottle are somewhat vauge and incomplete. It says use 10ml per 40 gal. once a day. It says nothing about how much alkalinity this dose actually adds to the tank, nor does it recommend testing to determine your maintenance dose.


if you are trying to increase alk it is recommended that you test for borate levels, as well as carbonate levels once you reach about 4.5mg/l of carbonate you will initiate precipitation, you can exceed 4.5mg/l by also dosing borate this is done over time with a supplement that contains borate.

The only kit I'm aware of out there that has both total and borate/hydroxide alkalinity tests is the SeaChem one...(which is what I use)

Since Borate is not used as much as carbonate for calcification, once you build up about a 1.2mg/l of borate you will be able to have about 4-4.5mg/l of carbonate the change will not swing so much because the borate will help neutralize the acids the carbonate will be used for calcification instead of carbonate doing BOTH jobs then you can attain a alk of about 5-5.5mg/l It is recommended to keep higher levels of alk to prevent PH shift and also to keep your SPS and other hard corals in supply of glue for the calcification process.

Ok...now here I think you may be getting things to far out of skew compared to NSW....which in my opinion is never a good idea. NSW borate alkalinity is usually around 0.15 meq/L., so you are running nearly 10 times that amount. Granted, I have seen where some claim this helps pH stability. Even if this is the case, at 5-5.5meq/L total alkalinity, you'll need a Ca level of 460-470ppm to maintain balance. Levels much above 420ppm Ca really don't help corals much, actually elevated levels of calcium can hinder coral tissue growth, because the coral is burning energy to rid itself of the Ca by building its skeleton, rather than spending that energy on tissue development . So what's the point of maintaining your alkalinity so high, other than to stabilize pH?

Also...since the borate alkalinity tends to stay in longer than the carbonate, if you are using a suppliment that has a larger ratio of borate, than logically the ratio in your tank of borate will climb, but at the sacrifice of carbonte. And since carbonate is the more "uesable", this isn't an ideal situation either.

Given those examples I would go ahead and start finding the source of the acids in your system, making sure feeding is not to excessive or old filters are cleaned or replaced. Acid buildup can also be staved with additions of oolite sand even at less than 1/2" this still remains effective. Feeding is the main cause of acid build-up, myself I feed about every other day sometimes more during my high temp cycle to simulate spring and summer.

Good advice....


Mike

[MikeS]

Here's a little more on Boron...

http://www.advancedaquarist.com/issues/dec2002/chem.htm

Elevated levels of boron are not good.....

MikeS

[MoonSoft]

Borate is another alkaline component in NSW yes the levels are higher this is done to stabilize PH swings, I also find it is a good pigmentation primer, when PH swings your corals metabolism staggers up and down, keeping a borate level a little higher will curb that behavior by limiting the range pf PH swing to normal patterns light nighttime and dawn

As quoted in that article
"In the case of normal seawater at pH 8.2, b = 0.19 meq/L/pH unit for the boric acid/borate system, and 0.63 meq/L/pH unit for the bicarbonate/carbonate system. These values are additive, and result in a total buffering of b = 0.82 meq/L/pH unit. Under these conditions, the boric acid/borate system provides about 23% of the total buffering, while the bicarbonate/carbonate system provides about 77%"

This is why I recommended not to JUST use baking soda for buffering capacity, since 1/3 of the buffering capacity is from borate elevating borate levels would make sense

I was hasty by making the statement that it's not a good idea, it's just I assume too many people hear about using backing soda instead of a buffer additive they completely remove the borate from the equation... hearing about someone's ph failing it simply made a recommendation that I have used in the past. And one, that has worked with many aquarists.

Having said that Mike you are right baking soda it a good additive, but with respect to boron in the tank I guess it's still a heated topic of debate, I think PH swings are more detrimental than more borate in the system.. Let me know what your thoughts are about this. It kind of follows suite to Strontium additives which I do not dose in my system period...... haven’t seen any negative effects as of late.

[MoonSoft]

I guess i should ask before posting an opinion didn't mean to start a flaming session

[MikeS]

I guess i should ask before posting an opinion didn't mean to start a flaming session

I think I was posting the boron article as you were responding....definately not a flame, just putting some information out there...I apologize if it seemed that way....I have no problems whatsoever with your opinions....anyway, I apologize if it came across like that... :-D

This is why I recommended not to JUST use baking soda for buffering capacity, since 1/3 of the buffering capacity is from borate elevating borate levels would make sense

Good point....boron will however find its way into the tank...ie by foods, dissolution of rock and aragonite, ect....Using alkalinity suppliments with boron isn't necessarliy a bad idea, I just think it can become problematic if the boron ratio is high enough that the ratios in your tank begin to exceede NSW ratios....

I was hasty by making the statement that it's not a good idea, it's just I assume too many people hear about using backing soda instead of a buffer additive they completely remove the borate from the equation... hearing about someone's ph failing it simply made a recommendation that I have used in the past. And one, that has worked with many aquarists.

Agreed, a low borate ratio is probably not an ideal situation either, but it is likely more safe both from a toxicity and an ioinc balance standpoint than a high ratio. From what I gather from reading, the main potential negative to low boron is the greater potential for pH swings. The role of boron in calcification is somewhat unclear.

I think PH swings are more detrimental than more borate in the system.. Let me know what your thoughts are about this.

There really isn't much information out on the effects of pH swings in our tanks, nor good evidence out there to suggest that pH swings are necessarily negative. There are obvious exceptions to this, like the pH greatly exceeding or dropping below the "normal" range...or a very rapid shift in pH. The pH of most tanks normally shifts .2 or so every day. There are of course certain tank inhabitants that appear to be more sensitive to pH than others, xenia for example. High borate, on the other hand, has been shown to be toxic.

I would say if the tank is staying between 8.1 and 8.4 pH, there really isn't much to woory about there. If maintaining pH is a problem, than finding the source of the problem (like CO2 buildup due to poor gas exchange) is more advisable IMO than greatly elevating boron.

Having said that, do I think boron is bad? No...but I don't feel it should be elevated much past NSW levels. After all, these levels are what these corals have adapted to in the wild, it makes sense to me to try and keep them close in the reef tank as well....
:-D

Mike

[MikeS]

I should add to the above it would be wise for anybody concerned with it to pick up a borate/hydroxide alkalinity kit...seachem has one for sure, I bet there are others...it never hurts to test...especially if you are playing around with the levels...

Mike

[MoonSoft]

Sweet i love the additional input i like seeing the other sides of this topic thanks for the info i am going to do some more digging and post about this asgain.. we need to add a reef chemistry topic that i think would be GRAND!!!! it would give people a chance to dive deeper and learn more.

I have never been on to keep it simple..... cuse failures in this hobby are expensive and emotional!

[MikeS]

Well, we'll have to find a chemist to moderate a chemistry forum...and I'm definately not a chemist...actually, I kinda hate chemistry, I kinda sucked at it in school.... :lol: But I've forced a good deal of it through my thick skull in the last 5 years because of my reef :lol: I'm kinda starting to get it now.... :-D

Mike

[bigfoot]

i have had problems with my tank with ph i have really aicdic water and with baking soda it still dropped and only thing i have found what works at stablizing it is kent marines 8.3 buffer it works great!

[MoonSoft]

Outstanding, i like some of the kent products but after talkting to one of their reps and asking some detailed questions to their tech support (chemists) i didn't like what i got, it seems their products are diluted to a degree that they want you to keep purchasing more and more... for instance their magnesium supplement vs Seachem i would say is about half as strong as seachems... as theirs is liquid... and it's about twice to 3 times as expensive!!!!

Their tech cb calcium i liked for a while but after dosing with Seachem i seem to see better results without dosing as much!! but now that i have a calcium reactor i dont does for those through either vendor!

let me know what you think

[bigfoot]

what i have done is for some reason the baking soda wont hold it on its own so i mixed 1tsp baking soda into their mix (container) and its worked awsome i havent had it drop for a week now even after topping off tank with 1 gallon de chlorinated water. im on artisan well water and it seems pretty good but in 3 mos my district will be building a TRIPLE REVERSE OSMOSIS PLANT and they promised that with only chlorine added so im pretty happy about it wish theyed hurry up!

[MikeS]

hmmm....now what exactly did you mix the baking soda with?

Mike

[bigfoot]

kents perfet ph 8.3

[MikeS]

what is your current alkalinity level at?

Mike

[bigfoot]

not real sure mike i have to wait tilli get some moolah this week cause the flowers eel and new ag canopy busted me for this week but for the fist week i had em ph wouldnt stick kept dropping even with perfect ph 8.3 still dropped slowly so then i did above and vioala it stayed ill get a kit by sat and ill let ya know

[MikeS]

how low would your pH drop?

Mike

[bigfoot]

7.6 7.8in there *this tank was non inhabited at that time*

[MoonSoft]

If i were you i would purchase one of those seachem reef status tests they are VERY nice, and as far as i am concerned they will last for a while and provide you with more alkalinity knowledge. Also if you are seeing this ph problem what are your tank specs???
gravel (type) (depth)
feeding regiment (frequency)
temp
salinity
and of coarse what other supplements are you adding, and what salt are you using for water changes..


i guess as much info as you can provide, sometime i see people using the wrong salt, or dosing with too many invert foods without proper filtration, all of these (acids) build up in the system and continue to decay, which could be the cause... also some people have noticed if thay keep large amounts of culerpa (macro algae) that the fish eating it releases some tanins in the water which in turn become acidic in the system.... i know a guy that said the problem dissappeared when he cropped his algae to about 1/3

let us know i am sure we can all widdle down the cause

Sincerely,
Aaron moon

[MikeS]

Agreed....new tanks that are establishing the biofilter and have a high nutrient level are more prone to low pH...reducing the acids and providing for good gas exchange will go a long way towards hitting the target pH...then you can start looking at "buffers" to keep it there.

Mike

[MarineScientist19]

eh, i just dose a lil bit of baking soda every water change keeps my buffer nice and high, lords knows my tap water is crap so gotta do what ya gotta do

[MoonSoft]

You might find that if you have "CRAPPY WATER" and dont have the $$$ to invest in an RO DI system get a 5 gal bucket fill it with water and mix calk.. all of your impurities will drop out on the bottom and the crust on the top, this would be a better way for you to add high alk and high calcium water to your system, and your phosphates and silicates would drop out of solution