Alk/Ca supplementation methods?

[Vauche]

Hello all and happy holidays.

I am looking to start automatic supplementation for Alk and Ca and have a few questions.

Currently I manually dose baking soda and Kent Turbo Calcium based on a dosing calculator. I am curious if one can dose baking soda as we would Kalk through a doser or auto-topoff (preferable an auto-topoff)? The reason for this is my pH runs 8.4-8.5 on a normal basis so there is little room for any pH increase that can be associated with Kalk.

Besides a calcium reactor any other mechanisms to auto-dose for calcium? I am aware that a calcium reactor/Kalk auto-topoff combo may be my best option especially with my pH being on the high side and the reactors ability to lower pH, but I am not familiar with Ca reactors and honestly at the moment they confuse the heck out of me. (I am still very much in the research phase of this process).

As added info, the tank is still young, aprox. 8mo. so only small SPS frags (but growing!) and there will be more SPS additions in the future.

As always, any info. is greatly appreciated.

 

[dots]

http://archive.reefcentral.com/forums/showthread.php?s=&threadid=102605


http://www.advancedaquarist.com/issues/feb2003/chem.htm

http://reefkeeping.com/issues/2006-06/rhf/index.php

 

[Vauche]

Thanks for the response. For sure a ton of reading ahead. Looks to be some good articles on the Ca reactors that I look forward to reading.

I have read several of those articles about Alk/Ca and supplementation and balance ect. and continue to re-read them and the others.

I guess a better way to phrase my question would be like this. If you have a tank with pH topping at 8.4-8.5 (low pH is 8.2-8.3) currently supplementing with only baking soda and Kent Turbo Calcium what automated method would you use to supplement?

From what I've read it would seem that kalk would not be feasible due to the possible increase in pH. Would this be correct?

Thanks

 

[tmz]

I would use a litre meter III dosing pump for both calcium chloride and the bi carboante.
Currently I use that pump to dose limewater(kalk). I also run a calcium reactor. The reactor is not terribly complicated. The limewater effluent ph at full saturation is12.4. The calcium reactor effluent has a ph of 6.7.

 

[dots]

Some balk at two part being "expensive", but weighed against the total sum of investment and new sources like bulkreefsupply, its minor and really most of the time justification not to..... I find two part to be the most straight forward and trouble free method available.

 

[Vauche]

Thanks for the input.

My biggest concern with the two part is the increase in pH. I suppose if one keeps on top of the situation though you should never have to add enough to be dangerous, at least until a 2 part becomes unfeasible or at least inconvenient.

Wonderful info, gives me something to think about along with my reading, thanks

 

[xJake]

Save yourself the time and money and go to bulkreefsupply.com or some other bulk chemical company and order the following: CaCl2 (calcium chloride), Na2CO3 (sodium carbonate; soda ash), MgCl2 (magnesium chloride), and Ca(OH)2 (calcium hydroxide; pickling lime/kalkwasser). 2-part does not increase pH, but kalkwasser does. 2-part will increase your salinity over time (due to residual Na and Cl), but this isn't an issue with regular water changes and salinity monitoring. Dose about 1 tbsp (15ml, or 3 tsp.) of Ca(OH)2 per 1-gallon (3.7L) of top-off freshwater that you add to your tank; do this every time you top-off, and keep doing it even while dosing 2-part. This will help keep your pH stable (especially at night when O2 is low, and CO2 is high) and will give you a base/main calcium and carbonate source. Then buy reliable test kits for calcium, carbonate(alkalinity), and magnesium. Use the results from these test kits and a reef chemistry calculator such as this one: http://reef.diesyst.com/flashcalc/flashcalc.html and correct your Mg first to the desired level (1300ppm is a good starting point). Then use this same calculator to correct your Ca, and CO3 levels. Keep a detailed record of what your test results are and how much you are adding every time you correct your levels. Over time you should begin to see a very noticeable pattern in your data, and you'll quickly learn how much you should be adding when you dose. I would recommend starting with daily dosing, and if your tank remains fairly stable over time then you can switch to dosing the amount needed every other day or only as needed.

2-part is probably the cheapest (up-front and over time) supplementation system available, and it has been used successfully for years. My LFS's owner told me about it years ago (apparently he used it to make his own salt mix in the 70's, and kept using it for supplementation), but I never started using it until I saw how widely it was used on these forums. It's a proven system, and I can't recommend it more highly.

 

[WaterKeeper]

Just to add here that two part additives will increase pH if they use Soda Ash, Na₂CO₃, to provide the alkalinity protion of the supplement. Those that use baking soda, NaHCO₃, do not usually increase pH so it is always good to know what you are using.

 

[xJake]

<a href=showthread.php?s=&postid=13978299#post13978299 target=_blank>Originally posted</a> by WaterKeeper
Just to add here that two part additives will increase pH if they use Soda Ash, Na₂CO₃, to provide the alkalinity protion of the supplement. Those that use baking soda, NaHCO₃, do not usually increase pH so it is always good to know what you are using.

I've always thought it was the other way around. Soda ash doesn't increase your pH, but baking soda will decrease your pH due to residual CO2. Maybe I'm mistaken... but why would replenishing used CO3 ions boost your pH beyond the normal seawater range?

 

[WaterKeeper]

Easy, the carbonate is a stronger base that the bicarbonate. Normal pH for a sodium carbonate solution is over 10.5 while bicarb only hits about 8.3. That extra carbonic acid in the bicarb is the difference. That is why you can heat baking soda and change it to soda ash by driving off carbon dioxide.

 

[tmz]

All in all I think all 3 methods: two part(calcium chloride and bicarbonate/carbonate), limewater, and /or a calcium reactor(primarily for larger systems) are good . Limewater and two part can be dosed manualy or with a dosing pump. They can be dripped from (a) bucket(s) or used with more elaborate top off/reactor systems. Don't really see much difference in start up cost between these two. If a bulk food grade lime is used ,limewater may be a bit cheaper.Any high ph issues with limewater can be offset with CO2 additions such as vinegar or seltzer or from a calcium reactor or in many cases by simply dosing the lime at night.

 

[xJake]

<a href=showthread.php?s=&postid=13978665#post13978665 target=_blank>Originally posted</a> by WaterKeeper
Easy, the carbonate is a stronger base that the bicarbonate. Normal pH for a sodium carbonate solution is over 10.5 while bicarb only hits about 8.3. That extra carbonic acid in the bicarb is the difference. That is why you can heat baking soda and change it to soda ash by driving off carbon dioxide.

Ah, ok. That makes sense. I guess I wasn't considering the pH of the supplements themselves while in solution. Thanks for the info.

 

[Vauche]

I definitely appreciate the little discussion here and all the input. Gives me many things to think about. As with anything else in this hobby, it seems mostly to end on personal preference.

With only a 90G I suppose any would work for a significantly long time. So, thanks again, it is now time to think.

 

[tmz]

You are welcome. Good Luck.