dKH and pH Problems

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awillemd1

Aquarium Advice Activist
Joined
Aug 29, 2003
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Location
Texas Gulf Coast
I have a 90 gallon reef tank and recently I have noticed that my dKH and pH tend to drop quickly after I add Kent Marine Superbuffer-dKH to bring the dKH back up to around the 10 level. I have also noticed that no matter how much Ca I add through the Kent Marine Liquid Calcium the calcium level doesn't go up. This last cycle lasted less than a week, i.e. I brought the dKH back up to around 10 then seven days later I remeasured it and it was around 6.4. Can anyone help explain what is going on here and what I need to do to get this under control? :?

Thanks in advance.

Willem
 
What types of animals/corals do you have other than fish and how's the coralline growth? Sounds like you might need to start a supplimentation scheme possibley.

What your experiencing is either a yo-yo effect from varying (unbalanced) additions or your tank is consuming the elements faster than your adding them. Doubt it's precip but please explain in some detail what you do for additions and how often, water changes and a list of animals.

Cheers
Steve
 
I only have a small yellow Tang and a spotted Hawkfish. For inverts I have about a dozen blue legged Hermits, 10 astrea snails, 2 brittle Stars and a red lobster. In the two months I have been starting a refugium with a dsb. I am using grap Caulerpa in the fug (that was the only macro they had at my lfs). To build up the dsb I have been adding a quart bag of aragonite play sand that I have been precuring in a cooler with saltwater. I would have thought the aragonite would help buffer the aquarium, but obviously that isn't the case. :?

Thanks in advance for any help.

awillemd1
 
awillemd1 said:
I would have thought the aragonite would help buffer the aquarium, but obviously that isn't the case. :?
The amount added by the dissolution of the sand is quite minimal and not really a contributor. It may slightly aid in an FO system although marginally, in a LR/reef system; it's not worth mentioning.

I still need to know how you have been using the suppliments? Amounts of each dose/frequencey of both alk and Ca. Based on the last post, you really don't have any largely CaCO3 consuming animals and you didn't mention coralline growth. The only thing I can surmise from that, is it's the way or amount of the additions are being made.

Do you have an Mg test or can your LFS test it for you? What salt do you use?

Most commonly, the easiest way to regain ionic balance in the waters chem is through a series of water changes (well aged/aerated). Once balanced, testing every second day for a week (both alk and Ca) to map out your rate of depletion will help you better understand what your tank is using and what you will need to maintain the level you want.

Cheers
Steve
 
Steve-s thank you for your reply.

I have only been dosing Kent Marine Liquid Calcium and the Kent Marine Superbuffer dKH as needed. That is, when I have noticed that the dKH is way out of line I have been using these additives. The amount I have been using is about 2 teaspoons of the Kent Marine Superbuffer dKH every 12 to 24 hours until the dKH reaches around 10. I have also been squirting in the liquid calcium. I have been less careful about an overdose of that as I have been told you can pour a lot in and not hurt anything.
Unfortunately, I don't have a Mg test kit. I will have to try my LFS. I use the IO salt and I always add extra calcium to it because it historically has come in around 350 ppm Ca.

The changes that have happened over the last two weeks is I have upped the hours of lighting from around 3 to around 8 or 9. I am still fighting hair algae, but I have dec ided with the additon of the refugium, the dsb and the Macro algae that I will try and use the algae to burn up the nutrients. This has clearly resulted in more hair algae growing as well as more coralline growth.

OK, I will plan to make several water changes, starting tonight. Once I get the system to a dKH of around 10 and a Ca level above 400 I will plan to test every other day for a week to determine my rate of depletion.

Thanks again for your help. :)

Willem
 
Steve is all over it. I would be amazed if it was not severly depressed mg levels, classic symptoms.
 
Thankyou, but how does that happen? :? What causes the Mg to be depleted all of a sudden? Should I be supplementing Mg?

awillemd1
 
awillemd1 said:
I have only been dosing Kent Marine Liquid Calcium and the Kent Marine Superbuffer dKH as needed. That is, when I have noticed that the dKH is way out of line I have been using these additives. The amount I have been using is about 2 teaspoons of the Kent Marine Superbuffer dKH every 12 to 24 hours until the dKH reaches around 10. I have also been squirting in the liquid calcium.
This is moreso what I've been suspecting. A larger less regular dosing routine will in most cases make maintaining balanced difficult to say the least. Smaller more regular doses would help solve your problem. If a large addition of buffer is added, it will have a tendancey to force down the Ca and vice versa when adding large amounts of Ca.

I have been less careful about an overdose of that as I have been told you can pour a lot in and not hurt anything.
For the most part this is quite true. What works best though is finding out what the total amount of additive (CaCl) is needed to raise the Ca to the desired level. Then simple divide that amount over 5-7 days if a large amount is needed. Twice daily additions being more advantageous than one large daily dose. The slower you increase the Ca level over several days, the less likely it will impact alkalinity if at all.

Unfortunately, I don't have a Mg test kit. I will have to try my LFS.
Might not be worth buying a kit but at least see if they can test it for you. Personally I don't test the Mg more than a few times a year.

I use the IO salt and I always add extra calcium to it because it historically has come in around 350 ppm Ca.......OK, I will plan to make several water changes, starting tonight. Once I get the system to a dKH of around 10 and a Ca level above 400 I will plan to test every other day for a week to determine my rate of depletion.
Be sure to correct the Ca imbalance before doing the water changes or you will have a much harder time of it. What is the alk level of the IO salts after mixing for a day?

The changes that have happened over the last two weeks is I have upped the hours of lighting from around 3 to around 8 or 9. I am still fighting hair algae, but I have dec ided with the additon of the refugium, the dsb and the Macro algae that I will try and use the algae to burn up the nutrients. This has clearly resulted in more hair algae growing as well as more coralline growth.
The hair algae could be contributing to the alk drop albeit quite small due to the cycle of growth and die off. It will also affect the CO2 at night depending on the density. I would urge you to run the refugium on a reverse lit timeframe from the main tank. This will help stabalize the pH and reduce the impact on alkalinity. The two algaes (main/fuge) will cancel each other out.

As far as the coralline, this is primarily your CaCO3 consumer at the moment. With the sudden increase in light you will most likely have seen some great growth due to the abundance of spores.

What causes the Mg to be depleted all of a sudden?
The are several things that can affect Mg, most commonly growth of calcerous animals but heavy additions of buffer compounds will cause it to precipitate naturally.

Should I be supplementing Mg?
Regular water changes should really take care of this for the most part. Sometimes it's addition is necessary but it really depends on your complete routine of supplimetation, what products you use and water changes performed. Two part liquid additives maintain Mg quite well without a stand alone additive. Small corrections can be made using epsom salts (magnesium sulfate predissolved in RO), larger additions should be corrected with water changes or a proper magnesium chloride additive.

Mg generally plays a large role in the balance but it's main purpose here is allowing Ca to saturate the water without precipitating. Think of alk and Ca like oil and water in a salad dressing, it tends to be at odds and separate. The Mg is the immulsifier that allows them to stay blended together.

When supplimenting with stand alone additives it's also important to use them in an order that most benefits the tank. Buffer/alk products best being used in the early AM. This allows for less of a total daily gain in the pH and less problems with pH spikes. Mg should also be added several hours later but before the Ca addition. If Mg is added to closely after a buffer, it tends to from carbonate magnesium which is largely useless to the system and precipitates out. With the proper additions made of alk and Mg earlier, the Ca added afterwards has a much better chance of staying in solution and gaining ground against the alk without either being affected by the others addition. Mg should be 3x the level of the desired Ca to be an effective control.

Cheers
Steve
 
Wow! Thank you for the detailed reply! :)

It will take me a while to digest it all, but obviously I will need to make smaller additions of my additives.

awillemd1
 
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