DIY Buffer

[Jimbo]

Hi was in bimart the other day and they had PH up for pools 98% sodium carbonate. Does anyone use this along with sodium bicarbonate(baking soda) as a buffer? Is it pure enough?

Thanks

[beach bum]

Bob Fenner recommends it (baking soda) in his book The Conscientious Marine Aquarist. I forget the dosage, but it's in there if you have it.

[seahawkjohnny]

Originally posted by beach bum
Bob Fenner recommends it (baking soda) in his book The Conscientious Marine Aquarist. I forget the dosage, but it's in there if you have it.

I used to use that for an alkaline buffer for freshwater tanks...

[Jimbo]

Sodium Carbonate, Bicarbonate

The combination of the two creates a buffering solution that keeps your tank PH and Akalinity stable. This is all the stuff that most reef buffers contain. Here's an excert from a previous thread by Tdwyatt

"The mixture of one part Sodium Carbonate to 8 parts Sodium Bicarbonate , when added at a rate of 1 level teaspoonful to each 25 US gallons of seawater, will raise the Carbonate Hardness by around 100 ppm (5.5 dKH to 6 dKH). I prefer this mix (heavier on the bicarb, and the carbonate makes up a smaller percentage of the mix) as Sodium Carbonate is such a strong alkalinizer. Dr Moe originally suggested that a mixture of 1:6 be used, where 1 tsp of the resulting mixture would result in an increase of 90 ppm or approximately 5 dKH hardness, but may result in larger swings in pH (especially to the high side) as the buffer system equilibrates. As there are many considerations in making this mixture, if you are not familiar with chemistry calculations, then continue to buy the super buffers (usually 1:8) or the reef builders (1:6) and use them as per labled instructions rather than make a dosing error by incorrectly making/measuring this buffering agent. btw, when adding the mixture, dissolve the dry mixture in about 8 oz of RO water and slowly add this to an area of high current/flow, preferrably in the sump.

Oh yeah, did I mention...

BAKING POWDER IS NOT SODIUM CARBONATE!!!"

[Doug1]

Jimbos right, sodium carbonat and Bicarbonate are two different things, if you are not comfortable with chmistry issues or Toms clear directions, dont try this at home

[tdwyatt]

Biggest problem making this if you are not familiar with measuring dry chemicals is calculating the water of hydration when figuring molar amounts of the two substances. Different crystalline forms of the salts have different weights for the same amount of a particular salt based on how much water of hydration each crystal form contains. Also, the lower the ration between the two, the more alkaline the final solution will initially start out as. Huge initial swings out to pH as high as 11.4 (for 100% sodium carbonate) can occur. Making the buffer solution and using CaCl2 as the calcium additive works well and is very cheap if it is properly made. It is much easier to just make kalkwasser and use a kalk reactor to supplement your top off water instead. Even if you make the buffer solutions, you still have to measure and slowly add these solutions/reconstituted powders to the tanks on a daily basis (home made 2 part additives). Might be ok to supplement or tweak the numbers, but 2 parts are more work than the Kalk top off process.

[Jimbo]

Thanks Tom,

My pharmacist says he has calcium cloride. If I'm using the powder stuff what would the ratio between the buffer and the calcium for proper buffering and maintaining correct PH along with alkalinity and calcium levels. I add kent 2 part at the moment, but have heard it can contribute to algea growth. It's a liquid so not sure of the concentrations.

Man just read the ingredients on the kent KH part here's what it says.

Deionized water
sodium
potassium
bicabonate
borate
fluoride
iodide
molybdate
selenate
vandae
tungstate

Here's the calcium part

Deionized water
calcium,
chloride
mangesium
strontium
bromide
lithium
rubidium
nickle chromium
zink
copper
cesium
iron
manganese
cobalt

thanks

[reefcam]

flouride???? Guess my SPS and fish will never get tooth decay....

and copper??? guess I'll leave the screws I dropped in the tank there....

[tdwyatt]

Originally posted by Jimbo
...what would the ratio between the buffer and the calcium for proper buffering and maintaining correct pH along with alkalinity and calcium levels... ...Man just read the ingredients on the Kent Alk part here's what it says (Alkalinity component): Deionized water, sodium, potassium, bicarbonate, ...

I personally prefer using the USV 2 part supplements, and although I have used the Kent products in the past, I see better results with the USV product based on pH shift after additions and the weekly values for Alk in the prop systems. The trace elements mentioned on the labels of both products are replaced by regular q 2week changes of 10% of the system's total volume with good synthetic seawater mixes. This negates the need for the additional trace elements, and although I have used them both in the past, I have seen no appreciable increase in algal blooms associated with either product.

The Alkalinity component of the USV (B-ionic) product supplies 2476 mEq/l or 6933dKh/l, so that 1 ml of the solution will raise the alkalinity of 3840 ml ( 1 gal. US) of aquarium water by 0.74 mEq/l (= 2.07 dKH). Should be easy enough to work backward to calculate the concentration of the molar amount of each ingredient in the mix to be added to a sufficient quantity of RO/DI to yield the corresponding solution. When making the solution, it will prolly be easier using water warmed to around 115F to speed the dissolution of the solids.

Reverse calculations should be even easier for the Ca CL2 part of the solution, as it is 54,000 PPM of calcium. 1 ml of the calcium (Component No.2) additive will increase the Calcium concentration by 16 PPM in 3840 ml (1 Gal US) aquarium water. This concentration of calcium is near the max solubility for calcium chloride at room temp, and it may require heating to some extent as well to speed dissolution. Avoid heating the water to boiling, as the solution will precipitate out excess CaCl2 as the solution cools.

When working with these compounds, keep in mind that they are both irritants to mucous membranes, caustic to even dry skin, and very reactive with metals (as in pots or mixing bowls), acids and bases. Once again, if you don't have experience with making these substances and doing calculations (including water of hydration estimates) for compounding dry chemicals, I would suggest that you buy the prepared products, as small errors in the compounding of these additives will have large consequences on the health and well-being of your coral wards.

How would you use these solutions??? add 1 ml of each solution to every 15 L (around 4 gal US) SEPARATELY into areas where there is good current (in the sump would be best) This should maintain alk in the 8 to 10 dKh range and calcium in the 350 to 375 PPM range, based on the number of calcifying organisms you have in your systems. This rate of addition is mearly a starting point, you may have to adjust you additions up or down based on system responses to these additions. The alk additions will prolly cloud the water in the immediate vicinity of the additions initially, but will quickly go into solution. I personally take a volume of RO/DI water and dilute the alk additive further prior to addition when performing alk additions.

Hope this clarifies things a bit.

[Jimbo]

Hi Tom,

Been refreshing my knowledge of molar solutions, how do I convert PPM to a molar value? I know that 1ml=1g H20, molecular weight of h20=10, which is 10g of H20=6x10^23 molecules. So if I want to get 54,000 PPM of calcium chloride I would use the following formula 54,000/1,000,000=5.4% calcium chloride in solution approxmatly. So .054X6x10^25=3.24x10^24 molecules. Molecular weight of CaCl2 is 40+35.45x2=110.

Ok now we know that 6x10^23 of CaCl2 weighs 110g and we need 3.24.x10^24 molecules

so 110g/6x10^23CaCl2*3.24x10^24CaCl2=594grams CaCl2 for about 1 liter of solution. Did I do this right?:P I don't think so, When you say part per million (of what)? I assume H20 probally wrong. God its to late to think about this, will revise it tomorrow. Since CaCl2 is a much larger molecule than h20 this is almost accurate, but I need to displace the extra h20 atoms and recalculate tomoroww!!!

Ok now I want to be able to add equal portions of Sodium/carbonate/bicarbonate mixture into 1 liter of water, what is the percentages and ppm values of of each of these that would mix with the above calculation for CaCl2 at equal strengths, I add 10ml of each of the kent every day. Kent has different stuff, this is where I am asking for your help.

-Thanks

[Jimbo]

^

[tdwyatt]

hey Jm, I will post an answer tomorrow. The water of Hydration refers to the amount of water trapped in the crystal lattice of some crystalline forms of solids. This makes weighing the solid a matter of adding up not only the molecular weight of the substance, but including the number of molecules of h20 trapped in the lattice as well. I will post some of the weights and conversion examples tomorrow, just too late tonight!