Anything to worry about?

[mooch1982]

Hey guys/gals,

Some history first. So i was struglling for the last two months with PH and Alkalinity in my 9 month old tank. My Calcium has been steady between 500-550 according to two diferrent Salifert Test kits. My alk on the other hand was dropping over the course of two months from 8 to 5.5. My Ph was also dropping over that same time period to as low as 7.38 at night(yes, I calibrated the probe to be sure!) and maxing out at 7.6 during the day.

So recently (2 weeks ago) I started adding kalk to my topoff water (1tbs per gallon), and my PH has stablized between 7.8 - 8.0. No worries there. Mag was raised to 1500 and has beens steady there (was at 1350 prior). Calcium has also remained steady at 550 (fluctuates +/- 10) weekly.

On the other hand, Alk has gone from 5.5 to 12. Coraline algae has started to take off in the past two weeks, and some of my corals are showing some growth agian (were stunted for two months), but should I be concerned with my alk being so high?

I run a pretty low nutrient system (nitrates 2-3 ppm, Phosphates .03-.08 according to Hanna) and feed heavy. I am using Prodibio as the source for bacteria and bacteria food and recently started dosing reef booster weekly.

I have lost a few corals, but that could be from the stress of low PH and Alk over the two month period prior. Many of my sps were bleaching over that time and some are recovering now showing new colors.

Sorry to provide so much information, but I think it's important so you can understand the state of my tank over the past couple of months. Any reason for concerns over the high Alk at 12??

Thanks in advance.

[Arc Drafter]

PH and alk are basically the same thing.

Can you give us more of an idea of your system?

Total volume
lighting schedule
water change routine
Stock list

Mag, Calc, and Alk all balance each other. if one gets out of whack then it will throw the others off. You really need to be sure to test all three and bring them back in together and bring your parameters back up slowly.

A good water change routine will solve a lot of your problems. IMO sounds to me like you are putting too much time between water changes and dosing. You should really do water changes at least ever 2 weeks and check alk, mag, and calc ever week and dose accordingly. This is what I do and there is never these large fluctuation.

here are my recommended stats
Alk 9
calcium 500
Mag 1350

[mooch1982]

Total water volume is 25 gallons with sump. Lighting is an ATI powermodule that gives 12 hours of lighting per day (5 hours full spectrum).

Water changes are done at 15% weekly. No exceptions.

Fish stock is moderate, sps..have about 20-25 small frags which are about 1-2 inches.

[disc1]

PH and alk are basically the same thing.


No, no they're not.

[jerpa]

The low alkalinity probably caused your previous troubles with PH. 5.5dkh is quite low. Your dosing is currently outpacing your consumption it appears. You can only dissolve 2 teaspoons of kalk per gallon of RO so you are dosing fully saturated limewater. If the alkalinity continues to rise I would add less kalk, maybe starting with one teaspoon per gallon. You will want to adjust your dosing so your alkalinity remains stable. This will require tracking your consumption. Test every few days and adjust the kalk you are adding based on those tests. Once the parameters are stable you can test less and increase the kalk to meet any increases in consumption.

[disc1]

My Ph was also dropping over that same time period to as low as 7.38 at night(yes, I calibrated the probe to be sure!) and maxing out at 7.6 during the day.

Any time you are seeing pH that low you have to question the measurement. At a pH that low the rocks and sand in the tank will start to dissolve and that will have a natural effect of raising the pH back up to at least the 7.7 area. A pH below 7.5 is darn near impossible to believe in a tank with any sand or rock in it.

What kind of probe and monitor? How was it calibrated?

Either way, pH is related to alkalinity and CO2 concentration. If alkalinity is right and pH is low then CO2 must be high. Getting some fresh air to the tank to help in the removal of that CO2 will help raise the pH, if it is really low to begin with.

[Arc Drafter]

No, no they're not.

FAIL

http://bit.ly/16mjLoT

Are you just looking to argue?

[disc1]

FAIL

http://bit.ly/16mjLoT

Are you just looking to argue?


You're kidding right???


Alkalinity is a measure of all basic units in the solution that are titratable with strong acid.

pH is a measure of the hydronium ion activity in a solution.

The two are not the same.

[disc1]

http://www.advancedaquarist.com/2002/5/chemistry

[Arc Drafter]

You're kidding right???


Alkalinity is a measure of all basic units in the solution that are titratable with strong acid.

pH is a measure of the hydronium ion activity in a solution.

The two are not the same.


I see what you are saying after your follow up with it and I looked more into the relationship.

[jerpa]

FAIL

http://bit.ly/16mjLoT

Are you just looking to argue?

I'm assuming you were going off the web definition which wrongly states alkalinity as being a PH above 7. Alkalinity will influence the PH of a tank, and generally keep it within normal values, however they aren't the same thing.

[mikecc67548]

Homonym? (http://en.wikipedia.org/wiki/Homonym)

[Trevor40]

I see what you are saying after your follow up with it and I looked more into the relationship.

It takes a good person to admit they were wrong. Tu-:thumbsup:che

[Arc Drafter]

Reply to all,

I really didn't think there was that much to it. I assumed measuring alk only was a good enough indication of where my ph was, and so far it hasn't been a problem. After looking into it further, I understand the relationship between ph and alkalinity better --other than ph >7.

[disc1]

I assumed measuring alk only was a good enough indication of where my ph was.

That is generally a safe assumption. With the way that seawater is buffered against changes in pH, if the alkalinity is right then it is pretty hard to get pH outside of the safe range. Too low and calcium carbonate in the rocks starts to dissolve and brings it back up. Too high and calcium carbonate starts to precipitate which brings pH back down.

[Arc Drafter]

That is generally a safe assumption. With the way that seawater is buffered against changes in pH, if the alkalinity is right then it is pretty hard to get pH outside of the safe range. Too low and calcium carbonate in the rocks starts to dissolve and brings it back up. Too high and calcium carbonate starts to precipitate which brings pH back down.


Yeah thanks for the clarification. I guess this turned into me getting advice. I hope the OP learned something too.

[tmz]

David explained it very well.

The relationship is a little tricky to understand.

It's not a homonym either. Alkalinity and pH don't sound alike; nor are they spelled the same way; they do mean different things.

Anything to worry about?

The drop in alk to 5.5dkh likely did some damage particularly to sps.

I agree the reported pH ,likely has some error in it.

The current 12 dkh alk is a bit high which may be an issue for sps particualry when using an organic carbon dosing sytem which via bacterial activity may deplete other elements they need to keep up with the acceelrated growth encouraged by higher alk..

FWIW, my sps do well at: alk 9.6 dkh, calcium 480ppm, magnesium 1450ppm, ,pH 8.15 to 8.30, sg 1.026/27, teperature 77 to 79.

[mooch1982]

Ok thanks guys,

I will consider cutting my Kalkwasser dose back to 1/2 teaspoon per gallon as opposed to 1 teaspoon per gallon.

I will test and see how that goes.

TMZ, do you think the damage to the sps could be reversed? I have had some frags die off, but others just looked bleached but are growing. Will those bleached sps recover if conditions are right? Or is it just too hard to say?

Thank again everyone.

[jerpa]

In time the sps should recover. They are particularly sensitive to alkalinity swings so if I were you I would work on stabilizing that parameter.

[mikecc67548]

It's not a homonym either.

pH greater than 7 are basic or "alkaline"? vs "alkalinity"? I suppose is what I mean in regards to homonymity. Am I wrong? Because I could very well be, as I so often am.

[bertoni]

"Alkalinity" in the context of reefkeeping has a reasonably precise definition. If you look in a dictionary, you'll get other definitions.

[athompson]

Yes its a homonym. A substance is an alkaline ( also known as basic) ifph is above 7. In this meaning, it is the opposite of acidic. Alkalinity in which we measure for is the buffering capacity of the water, meaning how " able" your water is able to buffer acids.

Just remember that all saltwater is an alkaline, opposite of acidic so that meaning is irrelevant.

[tmz]

I agree in the use of the term alkaline to describe the nature of alkalinity or pH homonymy fits better than with alkalinity and pH. In any case the point is pH and alkalinity have have different meanings.

To be more clear :
Alkalinity in seawater is : carbonate, bicarbonate, PO4 species, magnesium hydroxide, borate, and a few other actual elements . We measure it all collectively as total alkalinity. Since carbonate alkalinity makes up 96.5% of total alkalinity in sea water , a mesure of total alkalinity servers as surrogate measure for carbonate alkalinity which is the primary concern in terms of providing adequate bi carbonate for calcification to the organisms that need it.
Ph is a measurue of H+ or in more technical speak H+ potential.

[tmz]

TMZ, do you think the damage to the sps could be reversed? I have had some frags die off, but others just looked bleached but are growing. Will those bleached sps recover if conditions are right? Or is it just too hard to say?

I'd wait it out for the bleached corals, assuming you mean pale tissues and not bare skelrton.
They do come back sometimes. Maybe relocate them to slightly lower light.

Any with stn , I'd frag off dead spots and cut into healthy tissue a quarter inch or more ahead of the necrosis.