alk/dkh question

[tonkadawg]

I have been lurking here for a while, trying to learn as much as I can about sps systems in hopes of setting one up as successful like many of the ones I have seen here.

I have a general understanding of the calcium and alk/dkh relationship - keeping calcium 400 - 450, but my questions is about the alk/dkh part of the equation. I have read that NSW has a dkh of approximately 8. However, in reading many threads, I have seen several suggest keeping levels higher than this - say 9-12 range. Why is this? And if this is in fact a sound practice, what is the best way to achieve this, without having an adverse effect on calcium and ph levels?

[Habib]

A higher alkalinity might increase the coral growth rate.

The NSW value is approx. 7 -7.5 dKH.
If you have fast coral or coralline algae growth then the alk can be reduced pretty fast, and will change realtively much more than the change in calcium concentration.

So these are IMO a couple of reasons to maintain the alk a bit higer than NSW values.

I personally would not go above 10 dKH unless a calcium reactor is used and that is causing the higher alkalinity.

The higher the alkalinity the higer the tendency for it to react with calcium and form a precipitate of calcium carbonate which can not be used corals and such. It would also lower the calcium to undesirable low concentrations.

IMO I would say an alakinity of 8 - 10 dKH is fine. If using a calcium reactor than upto 12 dKH is IMO fine.

[Habib]

what is the best way to achieve this

If the calcium concentration is fine then using a buffer only additive is the right way to do it.

Besides commercial products you can also use baking soda or washing soda. If too much washing soda is dosed then the pH might rise too far.

[tonkadawg]

thanks for the clarification Habib

[Leishman]

My cal is 450 and my dKH only 4.6 (Last night w/Salifert)
Can I just dose the Alk part of Bionic to get this corrected?

[ReeferMac]

No. B-Ionic is a 'balanced additive', and things can get out of whack if you dose the two out of equal proportion. Better off using good 'ol Arm and Hammer Baking soda. Just mix a teaspoon or two into 1L of RO/DI and dump it in your sump, test again tomorrow.

- Mac

[Leishman]

Baking soda. Will that toss my pH out of whack?

[zanemoseley]

ReeferMac I hate to disagree with you but I've noticed with my tank in which I dose 12gal of kalk a week I have to add a unbalanced proportion of Bionic. I dose 4:3 ratio of the cal to alk to keep levels stable.

[jfinch]

Adding unequal parts of a balanced additve (such as B-ionic) is ok to do, but a waste imo. If your tank needs more of the alk component then add a little comerical buffer, baking soda or washing soda. If your tank needs more of the calcium compenent then add a little turbo calcium. The end results are really no different but you'll likely save a little $$$.

[ReeferMac]

Zane, I'd wager you have a magnesium issue...
I go through about that much Kalkwasser every 2 days, and had similar issue's, as my Mg. was getting out of whack due to the heavy kalkwasser use. I started using a little CarribSea Arragamight for some of the makeup water every now and then, and it has seemed to help.

- Mac

[Jive Turkey]

Baking soda is great for increasing alk, baking soda will lower the alk a bit though.

[Pygmey]

Please explain?

[jdieck]

Sodium Bicarbonate (Baking Soda) and Sodium Carbonate they both add alkalinity to the water.

They both react in the water to form bicarbonate and carbonate ions in different proportions depending on the PH level). While they react in similar fashion given the release or uptake of Hydrogen ions one decreases the alkalinity while reacting (The Baking Soda) and the other rises it (Sodium carbonate or Soda Ash used as a laundry booster) This drop or increase only lasts while the reaction is going on (12 hours up to four days) after which they both tend to return to a stable PH at 8.3

To minimize this tendency I add a bit of Sodium carbonate to the bicarbonate before adding them disolved in RO/DI water (About 5/6 of bicarbonate and 1/6 of carbonate). Although not ncessary I drip the solution to prevent an alkalinity shock to the critters.

[BLUE LAGOON]

Habib
I see you mention,when using 2 part additives,run your Alk,at 8 to 10 DKH.But running a reactor can go as high as 12 on the DKH.Did I miss something here?Why wouldn't they run the same ?Why would a reactor run higher? I was also wondering when running ALK even at 8 or even higher say 9 above.It's possible over TIME "sand bed " can turn into a rock form.Is this a true statement?If not at what levels, would this come into play?
Thanks for you input here......

[jdieck]

Originally posted by Jive Turkey
Baking soda is great for increasing alk, baking soda will lower the alk a bit though.

I think you mean baking soda will lower PH a bit... right?

[jdieck]

Originally posted by BLUE LAGOON
Habib
I see you mention,when using 2 part additives,run your Alk,at 8 to 10 DKH.But running a reactor can go as high as 12 on the DKH.Did I miss something here?Why wouldn't they run the same ?Why would a reactor run higher? I was also wondering when running ALK even at 8 or even higher say 9 above.It's possible over TIME "sand bed " can turn into a rock form.Is this a true statement?If not at what levels, would this come into play?
Thanks for you input here......

While we wait for Habibs input here is my thought sand experience. Normal Alkalinity and Calium parameters run in the range of 8 to 10 dKH for alkalinity and 380 to 425 for Calcium. Usually when using additives a high alkalinity depresses the Calcium and viceversa. Here is where the recomendation comes into play.

When using a single reactor you can keep the same balance. It is been said that higher Alkalinity and Calcium increases the speed of growth of SPS corals so you can artificially run higher alkalinity AND Calium by the use of Kalk Addition (or a Nielsen reactor) AND the use of a Calium Reactor. I have seen comments and read about some aquarists being able to maintain alkalinity as high as 12 to 13 while maintaining Calcium in the 500 to 550ppm. Of course they are side effects. Under this circumstances the water becomes so supersaturated that precipitation is likely to occur at the slightless seeding event.
Precipitation under this cirumstances can occur:

A) Increase in temperature: Basically incrustations of calcium carbonate will form in any heated surface. Pump impellers, UV sterilizer cuartz sleves, heaters etc.

B) Increase in PH: A sudden increase in PH will also increase the precipitation if combined with the increase in temperature. In addition if the increase is high and sudden enough you will get precipitation within the water itself (Not over a surface) creating the so damaging "Snow effect"

C) Cleaned or bare surfaces on existing Calcium Carbonate particles. This is very noticeable if new aragonite sand is introdced in the system as there is no "Protective" coating (That can be formed by Magnessium compounds) on the grains. This same effect can start forming within the sand bed to the point that the precipitation can start fusing together the sand grains forming a big chunck.

So in Summary, when using additives or a single reactor it is better to maintain an alkalinity in the 8 to 10 dKH level so as to facilitate maintainifn Calcium in the 400 ppm level.

If you wish to maintain alkalinity in teh 10 to 12 dkh level you can do it by either ramping up the addition of supplements which may in most cases require additional Calcium component or run a second reactor to keep this levels artificially high.

[slug]

Leishman:

Make sure you aren't looking at the meq/L column on the salifert test... 4.6 meq/L would be almost 13 dkh. You probably are looking at the right line but just in case...

[reefer44]

leishman:

hey its brad (met you at johns)

i dose half of my Kents B-Ionic all the time cause sometimes i need to increase my alk. and not increase my calcium or other way around...never had a problem

tonkadawg:

the higher your alk. the less your pH swings, but i still wouldn't keep it higher then 10 or lower than 9......this gives you a fairly stable pH and a more normal alk.

also i have heard some ppl have had better color with higher alk. but personally i have not noticed this in my tank at all (tried lower alk and higher alk over the period of about 4 months) although the tip color increased with higher dKh (around 12) but is the same now that the dKH is at about 9.2

Brad

[Jive Turkey]

Originally posted by jdieck
I think you mean baking soda will lower PH a bit... right?

Yeah, thats what I meant. That post was retarded and made no sense. oops!

Soory for the gibberish.

[Habib]

Originally posted by BLUE LAGOON
Habib
I see you mention,when using 2 part additives,run your Alk,at 8 to 10 DKH.But running a reactor can go as high as 12 on the DKH.Did I miss something here?Why wouldn't they run the same ?Why would a reactor run higher? I was also wondering when running ALK even at 8 or even higher say 9 above.It's possible over TIME "sand bed " can turn into a rock form.Is this a true statement?If not at what levels, would this come into play?
Thanks for you input here......

The higher the alkalinity and calcium are the faster it will precipitate as calcium carbonate. This calcium carbonate can not be used by corals and such and would be a waste of money.

When using a calcium reactor the pH is usually on the lower side and would make precipitation less fast compared to tanks with a higher pH.

Also, and that is somewhat a speculation, a higher alkalinity when using a calcium reactor might be required to let corals grow (faster).
Some studies have shown that the growth rate increases with increasing calcium and/or alkalinity but decreses with decreasing pH. So the relatively low pH when using a calcium reactor might be compensated by running the tank at higher alkalinity with calcium being in the normal or slightly elevated concentration range.

[Habib]

Originally posted by jdieck
............. I have seen comments and read about some aquarists being able to maintain alkalinity as high as 12 to 13 while maintaining Calcium in the 500 to 550ppm. Of course they are side effects. Under this circumstances the water becomes so supersaturated that precipitation is likely to occur at the slightless seeding event.
Precipitation under this cirumstances can occur:

..............................
...........
B) Increase in PH: A sudden increase in PH will also increase the precipitation if combined with the increase in temperature. In addition if the increase is high and sudden enough you will get precipitation within the water itself (Not over a surface) creating the so damaging "Snow effect"

..................................

Using a calcium reactor results often in a relatively low pH and is the opposite effect of what you are giving in (B).

[jdieck]

Originally posted by Habib
Using a calcium reactor results often in a relatively low pH and is the opposite effect of what you are giving in (B).

Sorry for the confusion. I agree with you when using a calcium reactor alone.

In the post above I was referring to running both, a Calcium Reactor and a Kalk or Nielsen reactor at the same time to artificialy maintain high alkalinity and high Calcium. In this case due to a fail in the Kalk reactor increasing the Kalk addition over the Ca Reactor addition the resultant increase in PH is what initiates the precipitation in an already supersaturated situation.

[tonkadawg]

Thanks for everyones input and explanations. Since I am not using a calcium reactor at this time, I will work to maintain calcium levels of 400-450 and alkalinity levels of about 8-10dkh.

On a side note, I was just thinking it is a shame now that I didn't do better in chemistry while in school...

[easttn]

If your Ca and Alk are out of whack, do a water change, then another, and another until its right. I used to add all the above and really paid for it when I broke down my first tank. The CC had turned to cement because of all the pH issues I created when adding the above ingredents. No other chemicals are needed (for Ca and Alk) if you slowly ease in the reactor to your system. Just my .02.