The Mg/Ca questions again

[SplendidWarrior]

Hey people, I've got another set of questions regarding Mg/Ca. The following are 4 days' worth of Mg/Ca readings, including SG, dkH, pH etc.

 

Day 1 Day 2 Day 3 Day 4

 

Ca: 240 260 280 240

 

Mg: 1080 1260 1260 1020

 

dkH: 18 20 20 21

 

pH: 7.91 7.93 7.91 7.99

 

SG: 1.022 1.023 1.023 1.023

 

My questions are as follow:

 

1. Had a double dosage of Ca today to try and bring it up to 400 but level fell by 40 instead. Why?

 

2. Same for Mg. but am quite concern why it can drop by 240 after given 1.5x dosage.

 

3. What affects the fructuation of Mg./Ca.?

 

Didn't do anything to the tank except giving regular dosage of Iodide, Mg., Ca. and added a large feather duster today.

[tinyreef]

first, let me point you to professional help, http://www.advancedaquarist.com/issues/feb...eb2003/chem.htm

 

it's a good read as all of holmes-farley (hf) articles and commentaries. not being a chemist like holmes-farley i'm gonna start talking outta my butt here:

 

it sounds to me like you're dosing CaCl as your calcium supplement. : you really need to balance that with some kind of carbonate source (e.g. baking soda) otherwise it'll suck it out of your tank (i.e. lower pH).

 

CaCl + H2O = CaCO3 (yeah, there's more, go ask hf) + HCl (probably what's knocking down your pH) the Mg is also going down as MgCO3 or is it Mg2(CO3)2 or something. go ask hf, he's the definitive source.

 

you may want to invest into a marine book like TRA I & II and read up on some of holmes-farley's articles.

[SplendidWarrior]

Thanks Tiny but err.., what are CaCl, CaCO3, HCI, MgCO3, Mg2(CO3)2??? Sorry pal but I failed my high school chemistry. Also, what does TRA stands for?

[Dave ESPI]

The Reef Aquarium.

 

if you failed chemestry, yer already at a loss in this discussion.

 

and don't use baking soda or powder in a reeftank. its Just NOT what to do.

[Twins Guy]

calcium chloride (CaCl2), calcium carbonate (CaCO3), hydrochloric acid (HCl), magnesium carbonate (MgCO3), The Reef Aquarium-Sprung, Delbeek (TRA)

 

tiny don't forget this is the guy that way overdosed some dupla buffer and his carbonate hardness still appears to be off the chart. according to rhf something like calcium chloride is an acceptable fixer-to get calcium and carbonate levels back towards

NSW (splendid-that's Normal SeaWater)-but you're right in saying that it is not an ionically balanced additive.

 

here:

http://www.advancedaquarist.com/issues/nov...ov2002/chem.htm

 

i'm referencing this article by rhf again because i think it addresses the root of the problem. splendid if you haven't checked it out already, do. you're in area 3. in addition to using CaCl2, rhf recommends water changes (since you're far from the target)-don't worry about deficient magnesium levels so much until you get your carbonate hardness (dKH) down as both mg and ca are gonna be difficult to raise. this is because both magnesium and calcium carbonate are pretty insoluble in water.

 

chemically speaking (for a second)...

CaCO3(s) -><- Ca 2+(aq) + CO3 2-(aq)

the solubility product for calcium carbonate (in pure water),

Ksp (CaCO3)= 3.8 x 10^-9,

is determined by multiplying the concentrations of Ca 2+ and CO3 2- in solution at equillibrium ->

Ksp (CaCO3) = 3.8 x 10^-9 = [Ca 2+][CO3 2-]

SO...in your case with [CO3 2-] being so big, [Ca 2+] must be small because only so much can be dissolved.

 

magnesium carbonate is relatively more soluble than calcium carbonate but still, the same high concentration of carbonate limits dissolved magnesium.

 

have to be careful saying that CaCl2 will cause your pH to drop. the concentration of protons H+ determines pH. CaCl2 adds no H+ to your tank and therefore does not affect pH. period. chloride ions are one of the major constituents of water, but

habitual addition of calcium chloride can cause chloride levels to far exceed those in NSW.

 

the dissociation equation goes like this:

CaCl2 -> Ca 2+(aq) + 2Cl -(aq)

 

distilled here's my recommendation for your problem:

>assuming that you're testing at the same time of day (could account for pH changes)

>assuming you trust or have double-checked the accuracy of your test kits

#1 stop magnesium additions until you're back in the hardness range.

#2 stop any pH buffer additions

#3 do more frequent water changes which will bring hardness levels down (and maybe other organic levels that are depressing pH) while normalizing pH

#4 use a calcium additive that adds ZERO carbonate hardness, i don't know if the seachem stuff qualifies or not-check the label, otherwise use a calcium chloride additive (kent turbo calcium for example)

#5 unless you're religiously testing for levels do not use iodine. this goes for everyone of you nano-reefers, as IME overdosing can lead to disaster and frequent small w/c s should replenish levels suitably.

FWIW-most iodine additives are simply potassium iodide which will NOT alter pH.

#6 when you get to target areas for calcium and carbonate hardness, start using a balanced 2 part additive. i'd recommend C-balance-two little fishies-that's all you'll need. It replenishes carbonates, calcium, magnesium, and all the other goodies in their proper ratios. HTH!

officially

tg

[tinyreef]

tg,

i was under the impression the Cl- ion looks for the H+ first. the strong acid HCl depresses pH by readily giving up H+ again. actually, i thought rhf wrote that somewhere. maybe tullock. i dunno, whatever. balanced additives.

[Twins Guy]

hey tiny-and tag alongs:P

 

well...the definition of a strong acid is one that "completely" dissociates/ionizes in water. so in reality the generic equillibrium equation that normally goes something like:

HA -><- H+ + A- becomes HA -> H+ + A-

therefore no matter how much chloride (A-) is pumped into that system you can't push the equillibrium back to the left leading to the formation of HCl. no s---! but it doesn't really matter. even if you want to say that it does become HCl and then quickly ionizes, the fact is that whether the proton was formerly in HCl or not doesn't matter...its in solution now, just as it was before you added your calcium chloride. make sense?

 

another important thing to remember is that the pH of normal saltwater is such that the concentration of OH- ions far exceeeds that of H+. if we talk about a tank where the pH (pH=-log[H+]) is 8, just for example, the concentration of OH- is 100x that of H+ (10^-6 vs 10^-8). by this logic it follows that for every proton there are 100 hydroxide ions that cancel out its effect (neutralize because H+ + OH- = H2O), and dominate the equillibrium mixture. therefore H+ shouldn't really factor in.

 

i'm working on the total picture, wish i could paint it for ya, you know like THE definitive explanation of saltwater chemistry. all these self-annointed chemists...i think we need a few less chem discussions written by aquarists, and a few more written by real chemists.

HTH (and isn't too confusing)!

tg

[Twins Guy]

tiny? tag-alongs:P ?

[SplendidWarrior]

Hey Twins, thanks for all your inputs on my problems. However, this is getting more confusing to me (not your fault). I wrote to A. Thiel about my high dkH/low pH. He recommended that I should bring my Ca/Mg up to optimum level of approx. 400/1300 respectively and my pH should go up. I've done exactly what he told me but it doesn't seems to be helping.

 

My pH dropped to 7.88 today together with my Ca to 220ppm. But what amaze me is Mg shot up to 1380 from 1020!? Is this normal or is there something really wrong!?

 

Having said that, if something is really wrong with my water chemistry, why are all my inverts, corals and fishes thriving?

 

Anyway, I'll do a wc today as you recommend and do nothing until I can bring my dkH down to a normal level. I checked with some lfs today about C-Balance but none have them and the only way I can get them is through mail order from the US which will cost a bomb to ship. Seachem's products are more readily available here and I was just wondering if any of these products may be a good sub for C-Balance. Thanks for helping pal. : )

 

Reef Advantage Calcium™ is equivalent to dry Reef Complete™. It is a non-caustic (pH 8.3-8.6) optimized blend of ionic calcium designed to restore and maintain calcium levels found in natural seawater. Calcium and carbonates are essential to all coral growth. If either becomes deficient, coral growth will cease, followed by a rapid decline in coral health. Reef Advantage Calcium™ also includes magnesium and strontium in amounts proportionate to typical utilization ratios (100:5:0.1, Ca:Mg:Sr). This allows one to maintain these two important elements while maintaining calcium. Unlike limewater (kalkwasser), Reef Advantage Calcium™ does not have a caustic pH and will not deplete magnesium. Used as directed, it will not deplete alkalinity. A 500 g bottle treats 16,000 L (4,000 gallons).

 

Reef Builder ™ raises carbonate alkalinity without immediately impacting on pH. With long term use there will be a tendency to stabilize at pH 8.3. Carbonates and calcium are essential to all coral growth. If either becomes deficient, coral growth will cease, followed by a rapid decline in coral health. Used as directed, Reef Builder™ will not deplete calcium, magnesium, or strontium which usually tend to precipitate with increasing alkalinity. Reef Builder™ and Reef Buffer™ may be used together. Use Reef Builder™ to raise carbonate alkalinity without affecting pH. Use Reef Buffer™ to raise carbonate alkalinity and pH. 500 g treats 32,000 L (8,000 gallons).

[tinyreef]

tg,

sorry, i was out of Internet-access land for a day.

 

i see your point (once my head stops spinning it will). my point wasn't so much really advocating the Cl- will push to make HCl as to try to justify why splendid's pH was so low. the CaCl needs to be balanced or it'll find it's own balance thru pH or salinity shifts was what i was babbling on about. again, whatever.

 

i'm just spouting out stuff i've read over the years. splendid did part of what he should do. go to the sources (i.e. thiel, rhf, sprung, etc.) or read their works. the second is easier imo but it's great when those great minds can spare the time for us noobs too!

[SplendidWarrior]

distilled here's my recommendation for your problem:

#1 stop magnesium additions until you're back in the hardness range.

#2 stop any pH buffer additions

#3 do more frequent water changes which will bring hardness levels down (and maybe other organic levels that are depressing pH) while normalizing pH

#4 use a calcium additive that adds ZERO carbonate hardness, i don't know if the seachem stuff qualifies or not-check the label, otherwise use a calcium chloride additive (kent turbo calcium for example)

#5 unless you're religiously testing for levels do not use iodine.  this goes for everyone of you nano-reefers, as IME overdosing can lead to disaster and frequent small w/c s should replenish levels suitably.

FWIW-most iodine additives are simply potassium iodide which will NOT alter pH.

#6 when you get to target areas for calcium and carbonate hardness, start using a balanced 2 part additive.  i'd recommend C-balance-two little fishies-that's all you'll need.  It replenishes carbonates, calcium, magnesium, and all the other goodies in their proper ratios.  HTH!

officially

tg [/b]

 

Hey TG, did what you recommended I do. Changed water twice in the past week and now carbonate hardness is at 15dkH. However, Mg/Ca is still hovering around 1100/300 ppm even after regular dosing.

 

pH is also hovering around 7.8/7.9. I thought I could live with a slightly higher dkH so I again added a small pinch of Seachem pH buffer to try and raise pH but I only managed to raised it by 0.1 pH before it goes back down again. The dkH didn't rocket like the last time though.

 

Looked for C-Balance everywhere here but couldn't get hold of any. But I've managed to order some Salifert test kits which I hope to get soon.

 

Anyway, I think I'm gonna give up trying to get everything to the right level. I'll just ensure that the pH doesn't crash and the NO2, NO3 as well as NH3 levels are ok from now on. I guess I'll try again with my upcoming 180-gallon. Thanks for your help.

[Dave ESPI]

Giving up is not a great idea.

 

Try a different salt brand and use a more pure form of water.

Chances are indeed that you may have some organics and a redux/ acid buildup in your tank that is making all your problems.

 

What are you running for rock, sand, lights, and filtration again?

What is in the tank livestock wise? and how long has it been running?

Some background information will help narrow it down a little more as to the root of yer issues.

 

TG's advice you quoted is solid, and I would indeed do more waterchanges.

[SplendidWarrior]

I'm not one for giving up really but I think it beats having spending all these time and money trying to correct something which might not be possible. This is after all just a hobby right?

 

Anyway, I think the root of all these is probably my extremely high bio load. This tank is only 3 months old and is very densely populated with fishes, inverts and corals.

 

My tank readings for NO2, NO3 and NH3 are zero and I was given the impression by some LFS people that as long as these readings are zero I can add more livestocks. I must say that even though its highly populated, all the fishes, inverts are growing and corals are propagating (some of these will go into my 180 when its set up).

 

Question: How does high dkH (25+) affects livestocks? ???

 

FWIW, here are my tank specs:

 

Tank and water:

4 gallon with conditioned tap water mixed with Tropic Marin salt. (Tap water here has pH7.2 and zero dkH )

 

Lights:

1 x 13 watt actinic and 1 x 13 watt daylight pc. On 11 and 8 hours respectively.

 

Filtration:

1 Eheim Liberty 100 hang on filter running with Dupla Minikaskades bio balls, Dupla activated carbon and Dupla Baccies; 1 Eheim 2006 internal filter running on Dupla Minikaskades bio balls and sponge prefilter.

 

Circulation:

2 small Eheim power heads

 

Tank Inhabitants (Looks like my wife's shopping list ):

- 10 lbs of cured LR that has been in a LFS tank for a year before I bought them.

- 1/4 inch of crush coral sand bed.

- 2 ocellaris clowns

- 1 yellow wrasse

- 1 yellow watchman goby

- 1 blues streak damsel

- 1 spotted mandarin dragonet (don't scream! Mine eats flakes and frozen bs.)

- 1 cleaner shrimp

- 1 red reef lobster

- 2 astrea snails

- 3 feather dusters

- 1 small rock of Maiden's Hair plant

- Assorted shrooms on rocks

- Assorted zoos on rocks

- Assorted star polyps on rocks

[Dave ESPI]

ok, just so you know... YOU DESERVE A SIESURE FOR THIS LINE.

 

I'm not one for giving up really but I think it beats having spending all these time and money trying to correct something which might not be possible. This is after all just a hobby right?

 

but I digress......

 

Get rid of the crushed coral. That is a serious part of yer issues.

you can add some aragonite sand into it also if you want to keep the CC in the tank fer now.

 

"Treated" TAP WATER? huh? Waht?

 

uhh ok d00der.... what is it treated with? TLC?.... shaken NOT stirred?

also, for a 3 month old 4 gallon tank, you are WAYYYYYY over stocked on fish let alone everything else. I sense a LOT of bad advice was thrown yer way that you simply accepted and plodded on without questioning it.

 

Normaly I'd flame teh hell out of you, but you haven't drooled like a reef'tard thus far, and I lack the energy right now.....

your life has been spared by the gods.

 

 

Fish excrete ammonia and ureic acids. There is yer Ca/Cao3 low PH reactant issues as well as the fact that there are no natural buffers in the tank(ie: Sand) that can counteract the ph reducing acids (just like in freshwater tanks) so you get a constant PH dropoff.

 

Crushed coral really doesnt buffer the water at all and when by chance it does (usualy at a Ph near 6.7), it is not releasing utelizeable CA or buffers, as the previously ancient living corals (yer crushed coral) has already ionicaly bonded the various elements and rendered them "used" in the biological system.

 

I dont want to "OVER Complicate" this for you as you have mentioned we are going right over year head in a previous statement (you DID post in advanced forum.... Waht ya expect? lolz ) so I will simply leave it at that.

 

HTH

[SplendidWarrior]

I'm afraid argonite sand will be almost impossible to get here in tiny Singapore. As far as I know, nobody uses anything else but cc here. :|

 

I will do something about the over population issue when I have the 180 set up.

 

I'm too drained to do anything major to the tank. I guess I'll leave everything at status quo and just check on pH and NH3, NO2 etc regularly. After all, this post started because of the high dkH (21) in my tank.

 

I have never had anything die on me since this tank was set up and no algae or suffering corals to speak of either. Also the pH has never gone below 7.8 even if I can't get it to remain at a higher lever. Will this be alright?

 

I mean I wouldn't be a 'slave' to this tiny reef if I had just let the high dkH and slightly low pH be right? After all I've read some articles by some reef gods on the Net that a high dkH of 22 is ok and don't sweat about a pH of 7.8.

 

BTW, nobody has ever given me an answer to what a high dkH of lets say.. 25 and above would do to livestocks. You wouldn't know the answer to that would you? ???

 

Oh, I actually posted my original question on the Beginners Forum but someone bumped my question here. I guess this is a BIG CAN OF WORMS I opened up huh Anyway, I hope other reefers will benefit from all these as well.

[Twins Guy]

man-sorry i lost track of this thread...i agree with dave that giving up ain't gonna help but honestly i think you've got bigger problems than high dKH (choke fish bra-ajroar?-inside joke). i think the biggest problem you'll encounter with high dKH is that your calcium, magnesium, and other ions are gonna be out of balance because of the extremely high carbonate levels. therefore some long term and or growth related issues may develop. think like calcium deficiency in children-not gonna have proper skeletal growth rates. my new advice, get the 180 setup, fast.

tg

[SplendidWarrior]

Welcome back TG. So you think I should forget about my 4 and concentrate on the 180 huh. Does that mean there's nothing I can do barring something drastic to set everything right on my 4?

 

About the Ca/dkH problem: I don't have any hard corals. That gonna matter much?

[Twins Guy]

hey splendid-

i just think that your tank is seriously overloaded (with fish to be specific) and that you're gonna have a near impossible time adjusting that pH. minus the hard corals i guess Ca is less of an issue but i guarantee you that even softies will do better when your parameters more closely simulate NSW conditions. that said, many reefers have adopted elevated calcium, alk and pH levels, that make their closed systems more bullet-proof, as ideal. obviously nothing beats nature! save yer money and time for that mini-ocean! if everyone's alive and happy keep doing what you're doing-less the pH adjustments (you said it never gets below 7.8-that should be fine-temporarily). GL!

tg

[SplendidWarrior]

Thanks for the help TG!

[Twins Guy]

you're very welcome splendid! thanks for posting about your interesting, albeit frustrating, situation!

tg

[Xavier]

I understand that levels are levels and should be as similar to NSW as possible.. after doing some research when I was starting up a tank, I remember it being said that as long as you can get them to pretty good levels, stability and consistency is the key.. being off a little here or there isn't critical if you can maintain it consistantly... I don't know if that holds water still.. but I thought it was interesting at the time..

[Twins Guy]

I'd be a firm believer in that theory!

tg

[SplendidWarrior]

Yeah Xavier I think you're right. Its so easy to get carried away trying to get everything to be perfect until you realize you've gone bankrupt and the wife's gone. I think most times it would be a futile situation at best trying to depict the exact ocean condition in our small closed systems. So I guess as long as nothing is dying, everyone is happy and the readings aren't too far off... I mean why try to repair it if its not broken right?