Low PH, High Alk

[traderiain]

Randy,
Have noticed over last four weeks that PH has dropped, from 8.2 to 7.9, and Alk has gone up over roughly the same period from 8dkh to 11dkh. I am running a Ca reactor and my calcium has also dropped off fro a stable 400 to approx 300ppm. I am contemplating adding a buffer to raise Ph and get it stable, but am worried that will raise alk too much as well. All other nitrates, phos are zero. How do I restore the balance?
thanks Randy.
PS I have replaced the ph probe on the American sensor unit recently and am still getting the same readings. recalibrated twice as well. Used a reagent test and it looks to be above 8 (hard to telll exactly)

 

[DrBDC]

A buffer will raise your dKh even more. I'd dose the ca only, check your mag as it will throw off your balance. Here is a good article Randy wrote regarding low pH. BTW, what brand of calibration solutions did you use? I'll post a link to an article he wrote on that too.

http://www.reefkeeping.com/issues/2004-09/rhf/index.php

http://www.reefkeeping.com/issues/2005-02/rhf/index.php

 

[Randy Holmes-Farley]

Right, a buffer is not a good approach.

You need to raise the calcium with calcium chloride, and it may be the reactor that is driving the pH down. As the link above shows, limewater or more aeration with fresh air are good ways to raise the pH.

This article may also be useful:

Solving Calcium and Alkalinity Problems
http://www.advancedaquarist.com/issues/nov2002/chem.htm


this calculator shows how much calcium chloride to use:

Reef Chemicals Calculator
http://home.comcast.net/~jdieck1/chem_calc3.html

 

[traderiain]

I am using American Marine Pinpoint calibration fluid. Thanks for your quick response. I will give those suggestions a try and get back to you with the results. One other question; Should I continue to dose with calcium chloride or is it used to raise and stabilize?
thanks again!

 

[Randy Holmes-Farley]

Calcium chloride is a good way to raise levels, but long term I think a balanced calcium and alkalinity additive system is better.

 

[traderiain]

The link that you gave me for the Reef Chemicals calculator does not provide me with the dosage of limewater to raise the PH. It gives the dosage for the Calcium Chloride, and Mag but not the lime. I realize that I will be dosing a smaller amount, but not sure how much. I do have a Kent 5gal drip doser, so I imagine it will be just an issue of the amount of time I actually dose. do you have any suggestions?
thanks

 

[DrBDC]

You don't necessarily use limewater to raise pH. It does raise it though. You use it to maintain your ca and alk levels. Just set the drip rate to replace evaporated water. You set it up to drip and monitor what the alk levels are(since they are easier to see a change than the ca). If you find your alk is drifting up, decrease how much lime is in the limewater. If you see it dropping, increase the lime mixed in.

 

[Randy Holmes-Farley]

Folks usually replace most or all of the evaporated water with limewater. You can start with about 1 level teaspoon or so of lime in each gallon of limewater,and adjust up (to 2 max) or down as necessary to maintain alkalinity. The pH will rise, and hopefully it is a suitable rise. If too much, aerate more or back off on the lime.

 

[traderiain]

thanks for all of the information. I will get to work on these solutions. I will let you know how things work out.
Thanks for taking the time to help straighten out the pfoblem.

 

[Randy Holmes-Farley]

You're very welcome.

Good luck.

 

[traderiain]

Randy,
I have now raised the calcium back to 400ppm, the alk is 9dkh, the magnesium was @ 900ppm, so i am raising it slowly to take it up to 1300ppm. I am adding limewater from a gravity drip system and am having some luck raising the PH. It is still 7.91, but I am happy just taking it slow for now. If it stops rising I will adjust the level of Kalk upwards until I settle around the 8.1 area.
Thanks so much for your help. Once again this site has proved itself a great resouce for the hobby!

 

[Randy Holmes-Farley]

That sounds like a good plan.

Happy Reefing!

 

[traderiain]

Randy,
A follow-up question regarding magnesium additions. Can the homemade magnesium part of your 2 part recipe for cal/alk, be dosed to increase mag. in my case? Or should I stick to the commercial stuff at the LFS? If I can do it with the epson salts, would I dose the same amount as per your article. ( 2 1/2 cups per) ?
As a side note, I noticed my PH dropping while my wife was running the dryer, which is in the same room as my sump, skimmer and cal reactor. When the dryer stops the PH rises again. Any thoughts?
Thanks again.

 

[Randy Holmes-Farley]

If the magnesium is that low, I'd worry that you'd be boosting sulfate pretty significantly if you used Epsom salts alone. A boost of 400 ppm in magnesium will boost sulfate by 1580 ppm. Since the natural level of sulfate is only 2700 ppm, that seems excessive to me, and I'd either use a commercial additive (ESV or Kent), or de-icing MAG flake from the Dead Sea Works.

Here's a section on that from my upcoming article:

Magnesium chloride hexahydrate made by the Dead Sea Works is sold at many home stores, including Home Depot. It is often labeled MAG Flake. It may be repackaged as meltsnow:
http://www.meltsnow.com/msds-mag-flakes.htm

It may also be available from these stores:

http://www.harveysalt.com/prod01.htm
http://www.meltsnow.com/products-dry-magnesium-chloride.htm



Substitutes for Dead Sea Works Magnesium Chloride Hexahydrate

The Dead Sea Works is a business unit of ICL Fertilizers. They sell magnesium chloride hexahydrate in the US as a deicer and also apparently to artificial seawater (salt) manufacturers. In the past, potential impurities (such as ammonia) have left many aquarists and even some companies wary of using deicing or any other grades of magnesium chloride hexahydrate. However, The Dead Sea Works company recently supplied a detailed impurity profile for its product listing most impurities (29 of them in all). None were high enough to be a concern to reef aquarists. Included was an indication that it had adequately low ammonia. Subsequent analysis by Greg Hiller of some of the supplied material confirmed that the ammonia is low enough to use.

The recipe above is based on the bulk density of the MAG Flake as supplied by the manufacturer. They also sell a pellet product. It may be OK to use, but probably has a slightly different bulk density (they do not provide it that I can find). Exact values for the magnesium part are less important than the other parts, and when using pellets Iââ"šÂ¬Ã¢"žÂ¢d just follow the directions as stated here for flake unless better information is supplied in the future.

At this time, magnesium chloride hexahydrate from the Dead Sea Works is the only such product that I recommend, but there may be others that are acceptable. Choosing other unknown brands may be fine, or not. Iââ"šÂ¬Ã¢"žÂ¢ve not tested them for purity.

 

[Billybeau1]

<a href=showthread.php?s=&postid=6619819#post6619819 target=_blank>Originally posted</a> by traderiain
As a side note, I noticed my PH dropping while my wife was running the dryer, which is in the same room as my sump, skimmer and cal reactor. When the dryer stops the PH rises again. Any thoughts?
Thanks again.

That is not unusual. My kitchen stove is close to my tank and when I've got all four burners going (cooking dinner) my ph drops noticably. Especially in the winter time when the house is closed up. Must have something to do with gas and CO2.

 

[Randy Holmes-Farley]

If it is a gas dryer then it will produce CO2, but should be vented. Another possibility is that it is acting like a ventilation system, forcing out CO2-laden air, and bringing in fresh air somewhere.

A gas stove will drive CO2 really high, and will drop tank pH. Even a lot of people standing around can have that effect.

 

[traderiain]

Randy,
I assume in the upcoming article you will be detailing the mix and dosing parameters. Will the article be on Reef Central or Advanced aqaurist? Thanks all for your input on the problem. It is much appreciated.

 

[Randy Holmes-Farley]

It will come out Feb 5 at www.reefkeeping.com

It has an improved recipe, and expanded dosing instructions, in addition to other info.