Replacing Red Sea Calcium+ with Calcium Chloride

aras · Mar 16, 2023

With seemingly never-ending Read Sea product price increases trying to go DIY route. Already replaced Red Sea KH with baked Sodium Bicarbonate. Now trying to replace Red Sea Calcium+ with Calcium Chloride Dihydrate.

My question is how much dry 77% Calcium Chloride do I need to dissolve in 1l RO water to get maximum or close to maximum possible concentration of the solution?

Also, Read Sea Calcium+ contains some Strontium. Do I need to add anything extra to account for that? I do around 10-15% bi-weekly water changes.

Sean Clark · Mar 16, 2023

I would look for something in the high 90 percentile to minimize impurities. Hexahydrate would be a better choice as it is more soluble at room temperatures than Dihydrate. Calcium Chloride Hexahydrate has a solubility in water of 81.1g/100 mL at 25 °C.

Randy Holmes-Farley · Mar 16, 2023

I do not think it is desirable to make a maximally concentrated solution, and I do not consider strontium a useful additive. But if you want it, you'll need to either getr strontium chloride, or some hobby brand of strontium additive.

My recommendation is to take the calcium chloride with baked or unbaked sodium bicarbonate, and make a two part additive out of it:

An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System by Randy Holmes-Farley - Reefkeeping.com

Randy Holmes-Farley · Mar 16, 2023

Sean Clark said:
I would look for something in the high 90 percentile to minimize impurities. Hexahydrate would be a better choice as it is more soluble at room temperatures than Dihydrate. Calcium Chloride Hexahydrate has a solubility in water of 81.1g/100 mL at 25 °C.

It's only more soluble than the dihydrate because it has more water in it. The dihydrate is the normal form manufactured for most uses. You cannot end up with more calcium and chloride in solution, or else the dihydrate would reprecipitate.

Sean Clark · Mar 16, 2023

Randy Holmes-Farley said:
It's only more soluble than the dihydrate because it has more water in it. The dihydrate is the normal form manufactured for most uses. You cannot end up with more calcium and chloride in solution, or else the dihydrate would reprecipitate.

I'm not suggesting that you would end up with more calcium and chloride in solution; only that it is easier to mix.

aras · Mar 16, 2023

Randy Holmes-Farley said:
I do not think it is desirable to make a maximally concentrated solution, and I do not consider strontium a useful additive. But if you want it, you'll need to either getr strontium chloride, or some hobby brand of strontium additive.

My recommendation is to take the calcium chloride with baked or unbaked sodium bicarbonate, and make a two part additive out of it:

An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System by Randy Holmes-Farley - Reefkeeping.com

Thanks. I won't worry about strontium then.

Yes, I used your article to make the Alkalinity Part (recipe 1). For Calcium, it says to dissolve 500g of calcium chloride to make 1 gallon of solution. I was going to do that, but I think this is designed to allow dosing KH and CA in the same amounts. Since I dose and test both separately I thought making Ca to maximum concentration would make life a bit easier by reducing the frequency of refilling the Ca part of the dosing pump.

Anything else I need to be aware of when switching from the Red Sea to this DIY method?

Hats_ · Mar 16, 2023

If I'm correct the Red Sea additive also contains Barium in some form, might be worth to look into the importance of that

Randy Holmes-Farley · Mar 16, 2023

aras said:
Thanks. I won't worry about strontium then.

Yes, I used your article to make the Alkalinity Part (recipe 1). For Calcium, it says to dissolve 500g of calcium chloride to make 1 gallon of solution. I was going to do that, but I think this is designed to allow dosing KH and CA in the same amounts. Since I dose and test both separately I thought making Ca to maximum concentration would make life a bit easier by reducing the frequency of refilling the Ca part of the dosing pump.

Anything else I need to be aware of when switching from the Red Sea to this DIY method?

You certainly can do that, but IMO, it is better to match the calcium dosing to the alk dosing and just make small changes from there over long term, as opposed to try to jigger the calcium up and down every few days based on testing that can not readily detect the day to day changes.

Randy Holmes-Farley · Mar 16, 2023

Hats_ said:
If I'm correct the Red Sea additive also contains Barium in some form, might be worth to look into the importance of that

It's most definitely not useful. It has no known biological role in any known organism.

Hats_ · Mar 16, 2023

Randy Holmes-Farley said:
It's most definitely not useful. It has no known biological role in any known organism.

intereseting, my grandpa's brother who has been reefing for over 25 years never stopped talking about barium and strontium... but not all he said made sense all the time although it is funny

Randy Holmes-Farley · Mar 16, 2023

Hats_ said:
intereseting, my grandpa's brother who has been reefing for over 25 years never stopped talking about barium and strontium... but not all he said made sense all the time although it is funny

lol

Strontium has long bee claimed by reefers to be needed, with the rationale that it is present in coral skeletons.

But that rationale is misguided, IMO, because it gets incorporated into abiotic precipitation of calcium carbonate at the same rate, just because it looks chemically like calcium and is incorporated by mistake. One does not use skeletal incorporation to suggest the corals need uranium or anything else accidentally incorporated.

There are a very few organisms that do have a strontium need, but we generally do not keep them in reef tanks.

i discuss strontium details here:

Aquarium Chemistry: Strontium and the Reef Aquarium

This article on strontium is the second of several that delve into a variety of issues involving magnesium and strontium.

reefs.com

aras · Mar 16, 2023

Randy Holmes-Farley said:
You certainly can do that, but IMO, it is better to match the calcium dosing to the alk dosing and just make small changes from there over long term, as opposed to try to jigger the calcium up and down every few days based on testing that can not readily detect the day to day changes.

Never had issues with different Ca and Alk rates. Once you establish the required dosing, it stays pretty stable. I.e. with Red Sea stuff, it was around 10ml Calcium and 60ml Alk daily.

But I'll try your approach trying to match the rates. I guess it would make it easier to catch any issues if something went amiss with the dosing pump or testing kit (which has happened in the past).

Randy Holmes-Farley · Mar 16, 2023

aras said:
Never had issues with different Ca and Alk rates. Once you establish the required dosing, it stays pretty stable. I.e. with Red Sea stuff, it was around 10ml Calcium and 60ml Alk daily.

But I'll try your approach trying to match the rates. I guess it would make it easier to catch any issues if something went amiss with the dosing pump or testing kit (which has happened in the past).

That can be fine, certainly, but there is a reason that folks invented two part systems years ago and still use them today, and one main reason is for the point I made about 1:1 dosing, which is especially useful in lower demand tanks where the calcium decline is hard to measure but the alk decline is not.

Before tow part systems, many folks would suffer from roller coaster dosing where they dose none, then saw a drop, had to dose a lot to match the drop, sometimes overdosed due to calcium test error, then dosed none again while it declined, etc.