New alk supplement

[TimT]

Hi,

Hopefully this info will answer your question. To start off I will try to explain a few things:

Sodium bicarbonate reaches saturation at 18°c(standing water at average room temp) with the addition of 203.81 grams per litre. At 35°c(warm water) the amount is 309.5 grams per litre.
~This figure was extrapolated from the Solubility in Water values on the Wiki site for Sodium Bicarbonate. Those figures are: 103gr per litre at 0°c, 693gr per litre at 100°c.

There is 3.78litres of water in a gallon

Therefore Sodium bicarbonate reaches saturation in 1 gallon of water at 18°c by adding 770.4 grams, at 35°c it takes 1169.9 grams. To allow a safety margin so we don't waste Sodium bicarbonate through precipitation it would be best to only add 725 grams/gallon at 35°c. The higher temp would aid in dissolving and then the mix would not precipitate as it cooled.

Coral Grow Alk, Aluminum free weighs 302 grams/cup, thus by adding 2.4 cups to 1 gallon of RO water at 35°c the solution is near saturation when it cools.
~you must tap the measuring cup several times while filling it to get this weight. I tapped it every time I added a heaping tablespoon to the 1 cup measure. If you don't tap the measuring cup you can be off by 30 - 40 grams.

By adding water to the sodium bicarb while it was cooling you were able to prevent more from precipitating out. Your concentration was probably higher than the one that had fully precipitated out. Hence the increase in Alk that was noticed.

Coral Grow Alk takes a little more effort to dissolve since it is not chemically made. When mixing in 84 grams per liter(balling method) the mix is transparent.

Hope this answered your question.

Cheers,
Tim