What's going on with my water chemistry?

[BigShot]

I've setup my 120 gallon + 70gallon sump.
In there I have ASM G-5 skimmer (like ER ES8-4+).
I dose ozone at 155mg/hr. Got fuge with chaeto.

Here's my water specs:

Temp: 80F.
ORP: 425.
pH 8.05
Alkalinity 7.
Ca - almost 500ppm
Nitrate, ammonia, nitrite, phosphates undetectable.

Magnessium: 1400.

I use Salifert kits for the tests.

My concern is that I'm not adding any Ca at the moment. The tank is 2 months old (100% newly made water, but used established DSB - from aragonite Caribsea sand and established LR - also home made lr mixed in (argocrete)).

2 weeks ago my alkalinity was 11 and Ca over 500ppm.
Today I tested at 7 alkalinity and CA still 500ppm!

So... how can alkalinity be going down with Ca staying so high ? Aren't organisms using this is proportion ?
Why is my pH low ?
What can I do? :-(

Thank you,
Luke

[aquababy]

The ammonia to nitrate process will drop your PH and also your ALK (the ability to mainatain that PH) without using Calcium. Calcium is used in the growth process of corals and calcareous algaes etc. and will use up ALK as well in the proess.

[BigShot]

aquababy, thanks for the note.
It doesn't fix my problem though. I still don't know why the readings are not normal.
Note that the tank is fully cycled. I've used LR and LS from a 2 year old tank. I know that Ca and alk are used up by corals. What I don't understand is the abnormal pH, and the drop in alkalinity with no drop is Ca.

Cheers,
Luke

[thackray]

You are right, corals and calcareous algae should be depleting calcium and alkalinity together. Somewhere you are producing organic acids that are eating up your alkalinity. You have a lot of fish (detritus) but the corals you list are not particularly calcium hungry. Your fish load may be catching up with you. I think your ORP reading is being kept high by the ozone reactor masking another acid producing problem.

You seem to be wondering if your sands and rocks could be providing calcium but everything I’ve read indicates that rocks and sands are inconsequential producers of calcium unless the pH is very low

[BigShot]

But would the 'acids' (from bio load, whcih is high in my tank) still be produced despite the a) super strong skimmer b) ozone c) chaeto in the fuge d) nitrates and phosphates being 0 ?
I must note that I'm also having a bad hair algae problem... even though phosphates and nitrates are at 0... and I have 500ml of Rowaphos besides the chaeto macro in the fuge...
The question remains... what is going wrong and how can I help it.

Thank you,
Luke

[thackray]

One common and bad form of phosphate is not picked up by the typical test kit.

For solutions, wait for Randy to speak.

[Randy Holmes-Farley]

Let's back up for a second.

If you start at 580 ppm calcium (which is 550 ppm +) and you calcify to deplete alkalinity by 3 meq/L (8.4 dKH), the calcium will drop by the expected 60 ppm calcium, and the calcium will still be 520 ppm, which is still 500 ppm +.

So from the data given, I do not see any need to invoke anything unusual. You need to accurately track calcium and alkalinty additions and changes for quite a while to say that they are not in balance, and most folks that do so, find them to be accurately in balance, despite the initial appearance that they are not.

However, it is well worth asking why the calciuum is high. If you've added no calcium supplements, then perhaps it is a faulty salt mix, or a faulty kit.

What salt mix are you using? Have you measured the calcium and alkalinity in it?

Are you using tap water (which can have a lot of calcium in it)?

The pH is not unusually low. How did you measure it? If it really is on the low side, then more aeration, or using a high pH alkalinity supplement for your alkalinity needs can help raise pH. This article may help:

Solutions to pH Problems
http://www.advancedaquarist.com/issues/june2002/chem.htm

[jdieck]

I noticed two things that may be affecting you:

a) Ozone 155 mg/hr ORP 425 That is relatively high try to reduce your Ozone to 75 mg/lt and keep your ORP below 400 (375 more likely)

b) How well cured or how did you cured your home made live rock (Aragocrete), Not well cured aragocrete can affect your chemestry.

[BigShot]

Hi Randy and others, Randy here's the followup:

>Is CA supposed to be at 580ppm after RO + saltmix ? I thought it was close to 400 (Instant Ocean).

However, it is well worth asking why the calciuum is high. If you've added no calcium supplements, then perhaps it is a faulty salt mix, or a faulty kit.

>I'm using brand new Salifert kit. I didn't know salt mix (Instant Ocean) could go 'faulty'.

What salt mix are you using? Have you measured the calcium and alkalinity in it?

>Nope, but I'll do that.

Are you using tap water (which can have a lot of calcium in it)?

>No tap - RO.

The pH is not unusually low. How did you measure it?

> Milwakee monitor - calibrated right before using it.

If it really is on the low side, then more aeration, or using a high pH alkalinity supplement for your alkalinity needs can help raise pH. This article may help:

Thanks Randy,

jdieck - rock is cured. It's been over 4 months since it has been made. It went through proper curing and was in stable tank before.

thanks again,
Luke

[Randy Holmes-Farley]

So you get 580 ppm for calcium in fresh salt mix before adding anything except salt and water? That indicates either a bad batch of salt mix, or a faulty test kit. There have been bad natches of IO around that have elevated calcium, but in the cases that I have seen (mostly sold in Canada) the paramaters are way off, and the salt water actually precipitates CaCO3 after sitting a little while.

You might check with Habib in the Salifert forum at RC to make sure the kit is OK and that you are using it correctly.

[BigShot]

Randy, I'm not sure if 580 ppm is at the start, you mentioned that in your response so I thought this is what I start with :-).
The mix I bought was indeed in Canada and it was from BigAl's.
How can I verify a bad salt mix (besides elevated Ca) ?

Thank you,
Luke

[Randy Holmes-Farley]

Randy, I'm not sure if 580 ppm is at the start, you mentioned that in your response so I thought this is what I start with

Sorry, I should have been clearer. Mine was a hypothetical showing how calcium could be 500 ppm +, then drop due to calcification, taking down alkalinity by the amount indicated, and calcium could still be 500 ppm +.

So what is the calcium in the fresh artificial salt mix that you are using?

[Randy Holmes-Farley]

Here's the thread on the ba IO batches. Those had excessive alkalinity, not clacium, but serve to show that bad batches do show up once in a while.

http://archive.reefcentral.com/forums/showthread.php?s=&postid=1838939#post1838939

[BigShot]

I don't know... the bucket is empty so I'll have to buy anoother batch of salt soon...
I added a bit of sodium bicarbonate today to bring the alkalinity up. To my surprise pH dropped a bit...

I'm thinking if me adding Seachem Calcium polyglucanate (or something like that) had any effect on driving the Ca high and alkalinity down.

Anyway, even though I can't check the Ca level in the original salt now, I know that it was 470 3 weeks ago...
So the bottom line seems to be that Ca is increasing and alkalinity is depleting... this is what puzzles me. I've added Ca polyglucanate, but it was only 3 times at half the recommended dose...

I've also dripped Kalkwasser for about a week at that point the Ca was 480 and alkalinity was 11. Now, 2 weeks after I stopped Ca polyg. and Kalk the alkalinity went down and Ca went up... this is what confuses me... I thought the aragonite sand was melting, but then again the alkalinity would go up, too... perhaps it's the Ca leaching from home made live rock... it's become very fragile lately and seems to break much easier...

All quite confusing :-(

[Randy Holmes-Farley]

I added a bit of sodium bicarbonate today to bring the alkalinity up. To my surprise pH dropped a bit...

Baking soda does that. :)

I'm thinking if me adding Seachem Calcium polyglucanate (or something like that) had any effect on driving the Ca high and alkalinity down.


Sure it would, if you add enough to boost calcium significantly. It doesn't sound like you added much, however.

It is possible that calcium is leaching from the artificial rock. How did you make it?

[BigShot]

Randy, I bought it from a guy selling it on eBay, dry... :-(
I will contact him and ask him.

Thanks again,
Luke

[Randy Holmes-Farley]

You're welcome.

Good luck. :)