Is Calcium Necessary?

[bobrfish]

I have been checking this

calcium theory out.

I used a water hardness test kit from Tetra and have also compared

these results to those performed by company selling water softners.
Water hardness may and

will include divalent cations other than calcium. However, city test report indicates that calcium

represents greater than 95% of divalent ions in tap water.
Currently all water is passing

through a softner stripping hardness out of water. One recent check revealed 15-20 ppm hardness.

Reset water softner and water tested at zero ppm hardness. I presume that some calcium scale

remained in the tanks, the tanks were filled with water containing 350-400 ppm calcium prior to

change. Leaching of residue calcium from scale is possible and would vary from tank to tank. Even

so, calcium concentration must be low and dropping lower with each water change.
Substrate in

tanks is sand or red flint gravel (sand blasting gravel). Neither is known to leach calcium.

Cichlid adults from all areas - no effect

Breeding results thus far:
Lake

Malawi no effect
Lake Victoria no effect
Lake Tanganyika no effect on Julidochromis,

Neolamprologus, Cyprichromis
Central America no effect on Vieja, Hericthys, Amphilopus
South America no effect on Geophagus steindachneri

Fry raised did not suffer greater

mortality than fry raised prior to switch.

At some point I will switch some tanks back

to hard water. Probably Lake Tanganyika tanks with some species that have not bred yet.

[DogFish]

Chemical Constituent of

the Rift Lakes

Total hardness as calcium carbonate CaCO3 (mg/L)

L. Victoria

19.12--70.83

L. Malawi 60.58--85.60

L. Tanganyika 186.33--

460.0

[Mrfiremouth]

Bob,
not sure

what or where you are headed with this.
I usually boost Calcium in my fry tanks to help aid in

fry development.
I am unsure if there is a study showing any gains, but Jack Whatley wrote

once in an old article that he saw no problem with people raising Discus fry in Hard water with

higher levels of Calcium and that he thought it would benefit the growth rate of these fry.(It was

in his TFH series, but I can not remember which one).

I read this about mid 90's and

have always boosted water hardness for fry since. Not sure if it has positive or negative impact as

my fry loss is usually do to me not feeding the fry tanks enough during that crucial first 3 weeks

of life.

[bobrfish]

I do not see a problem

with raising fry in hard water tanks either.
Is there evidence that calcium concentration in

water is coorelated with fry health and growth or is it supposition?

[DogFish]

Do you have a conductivity

to measure the water coming in to the house before it goes through the softer. Then the water after

it goes through softer?

Have you checked your Alkalinity?

Something I've

learned is that L. Victoria and L. Malawi, the water is not as hard as I thought it was.
Only

L. Tanganyika would be consider a hard water lake.

[bobrfish]

I do not have a conductivity

meter.
Alkalinity or carbonate is unchanged, it remains at 350 ppm

[DogFish]

When you start adding or

taking away chemicals in the water. Ionic imbalance occurs when Chloride and or sodium become

major anions. The reason I asked about a conductivity meter was so I could work out your Osmotic

Pressure.

Freshwater fish need to maintain a higher level of salt then the water there

in. If it gets out of balance it can cause the fish to be stressed out.

I'm learning

about this myself. if you get the ionic and osmotic difference between the the fish and the

aquarium water it can cause undue stress on the gills.

[bobrfish]

At what ionic concentration

and osmotic pressure are freshwater fish gills under undue stress?

[DogFish]

I"ll work out L.

Victoria.

Electrical Conductivity-----91-145 microsiemens for this example I'll use

the figure of 120 microsiemens.

The next thing is to take conductivity to Total

dissolved solids, a little math.

To get from conductivity to TDS you need a conversion

number for the City of Tampa the water dept gives it at .61 every water dept has a number.

For L. Victoria I know the TDS ranges 58.24--118.0 to get my conversion number I divided 91 by

58.24 and rounded it off .63 which is my conversion number for L. Victoria.

120 x .63 =

75.60 ppm which is my TDS number.

take that number divided it by 100

75.60divided by 100 = 7.56 lbs per square inch . Lake Victoria has a osmotic pressure around

7.56


with these formulas you can use on you own aquarium.

Total

Hardness; Calcium, Magnesium, Alkalinity (Calcium Carbonate) and so on. There have conversion

factors also.

You can take The approximate TDS subtracting the total ions from it.

To answer your question Is calcium necessary, I would think that it helps with the ionic

balance which osmoregulation relys on.

[bobrfish]

I missed something in the

last post. What is the number at which undue stress to gills occurs?

Sodium has

replaced calcium in water via water softner, thus ionic strength remains the same and osmotic

pressure is actually higher in this water.
That is because osmotic pressure is based on

particle in solution. Take out one calcium particle and replace with two sodium particles. Thus

osmotic pressure is increased.
Ionic strength remains the same. as one calcium ion has plus 2

charge and it is replaced by two sodium ions each with a plus one charge.

[DogFish]

The idea is to keep the

water in aquarium in the range of the fishes native habit.

OSMOTIC PRESSURE

Is the hydrostatic pressure produced by a difference in concentration between solutions on the

two sides of a surface ( a gill cell ). The cell of a fish gill and the surrounding water.

Ions that were in balance in the natural water (tap water or water source) are completely

out of balance.

I assume your water softer uses salt replacing the calcium. So by

replacing the calcium with sodium you are now making Chloride and or sodium the major cations or

anions in the water.

[bobrfish]

It is true that calcium is

out and sodium is in when using a water softener. Chloride is not added to softened water,

chloride is lost down the drain when sodium binds to anion resin in water softner tank.
As far

as natural water goes. It would be amazing if the ionic composition and osmotic composition found

in water from the city of Apple Valley matched that of SA, CA, Lake Victoria, Lake Malawi, Lake

Tanganyika or any other natural water from which cichlids are taken.

My question

remains, at what osmotic gradient or ionic strength does undue stress on gills occur?

[DogFish]

A lot of this is new to me

and I"m doing a lousy job explaining it. Give me some time to think about your question and

I'll get back to you.

[Mrfiremouth]

Bob, been doing some

searches on softeners....
<a href="http://www.angelfish.net/VBulletin/showpost.php?

p=84826&postcount=18"

target="_blank">http://www.angelfish.net/VBulletin/showpos...mp;postcount=18</a>

http://www.angelfish.net/VBulletin/showpos...mp;postcount=35 (http://www.angelfish.net/VBulletin/showpost.php?p=88982&postcount=35)

http://www.angelsplus.com/ArticleOsmosis.htm

[bobrfish]

Rich,

The first

article is wrong regarding osmotic pressure. It does not remain constant, but increases as 2

particles replace 1 particle. This is a bit easier for fish as increasing osmotic pressure allows

fish to use less energy to maintain particles in tissues and blood stream. Also, it is always

confusing to discuss particles that create osmotic pressure with ions and ionic strength. That is

not all particles that create osmotic pressure need to be ions but most are in fact ions.

All the articles imply or state sodium is harmful but calcium is not. My expierence suggests

these statements lack evidence to that claim.