Reef Chemistry - Need to raise Alk

ALKANITY AND CALCIUM

The addition of supplements is very common in the hobby. The first and most important supplement to consider is dripping Kalkwasser at night as top off. This supplement is not only a good source of equal amounts of Alk and Ca, it also has the added benefit of stabilizing pH. At night when photosynthesis switches off, algae becomes an oxygen consumer and Carbon Dioxide producer. This drop in pH is a common cause of stress, disease and sometimes death of fish, nor is it good for inverts, including coral. Kalkwasser is a long standing proven method for keeping a well maintained reef aquarium.

If the tank has enough growth that Kalkwasser cannot add sufficient Alk and Ca, the second supplements to consider are a 2-part solution of Alkalinity and Calcium. The surprising thing to new hobbyists is that these supplements can be made at home with some ordinary household products, Baking Soda and Ice Melt. Here below I have written about how to do it. This is the easiest of supplements that will do the most good for a reef tank. I highly recommend it.

The third and final method of adding Alk and Ca is the "Calcium Reactor". So called because it is a semi-automated way to give the stony coral the Calcium they need for skeleton growth. It's not an accurate name but it has stuck so we use it. A better name would be the "Carbonate Reactor". It adds Calcium and Alkalinity by dissolving Aragonite, the same substance we use for sand! The resulting Carbonates in solution are pumped into the tank at a rate set by the hobbyist. This is the most complicated method of adding Alk and Ca and is practical only for those tanks with a large percentage of stony coral. It's downsides are cost, the inadvertant decrease of pH, the complications of setting and continual monitering of several flow rates and the need to bump up the Alkalinity periodically with the Alk side of the 2-part solution.

There is one thing to consider, the more we ignorantly mess with the chemistry of our tanks, the worse they fare. A water change is always the safest way to reduce any excess.

Making and adding Alkalinity and Calcium to the reef aquarium

Alkalinity: 4 parts Baking soda and 1 part Soda Ash/Washing Soda. Soda Ash is made by baking Baking Soda in a glass baking dish at ~400 for an hour or so. Dissolve as much of this as will dissolve in purified water, then add it regularly along with doing Alkalinity testing to be sure of dosing the right amount. The desired range is 8-14 dKH or it's equivalent in meq/l or ppm.

Calcium: Dissolve as much Calcium Chloride (Peladow brand ice melt or CaCl2 from a chemical shop) as will dissolve in purified water. Dose it separately from the Alkalinity additive. Mixing the two together or adding them to the aquarium where they can mix too soon is ineffective and forms solid Calcium Carbonate in a chemical reaction typically described as "snowing". But dose this Calcium additive on the same schedule as the Alkalinity, using an amount based on the need as determined by Calcium testing. 350-450ppm is the desired range.

Determining the correct amount to dose: For example, taking a 100 gal tank, I would start by testing the Alk and Ca levels. If either are out of the desired range, I would add ~1/4 cup of the needed component solution, then test the next day to see what difference it made, if any. Then adjust the dosage accordingly, testing and watching the levels daily (or weekly if you are lazy like me

) until I had figured out about how much to add to replce what the tank is using.

Tip: Dosing at the same time as feeding, helps keep it fairly regular and consistent.

Tip: Reef aquariums can handle it if the dosage moderately exceeds the levels of the desired range. Simply stop dosing for a few days and let the tank take care of the extra through natural processes. If a large amount is accidentally added (dang kids

) a partial water change can help alleviate a problem

So im going to go to the grocery store to buy some baking soda tonight, and bake a portion of it to make the soda ash. Im not sure how much to mix together, and in how much water..? Once i get that figured out, how much should i add to to the tank to raise my alk, and how quickly can i add it, and where should it be put in the tank or sump? Sorry, lots of question. Guess i should also tell you what my levels are. My alk is at 6 dkh, Cal is 390, Mg is 1290, and PH is about 8.0

Im trying to think of everything that mark is going to ask me in advance... My tank is 125 gals with about 150lbs of live rock (havent actually weighed it to know for sure LOL

), 3 in sand bed, 55 gal sump about half full of water with my skimmer in the first chamber, refuge in the 2nd chamber with about 4in of very fine sand, rubble rock, and chaeto, and then 2 return pumps and one pump for my uv sterilizer in the final chamber.

and here is a pic of the tank when i first set it up

Thanks in advance for your help