# [Wet Thumb Forum]-A little confused.. does Crushed coral have Calcium and magnesium?



## sherry (Sep 30, 2005)

some posts suggest using cc and epsom salts..for a ca/mg balance... others say just use cc. 

Since I've just added a bit of cc to my filter, I was wondering what the benefits beyond co2 stability might be... 

thanks


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## imported_carpguy (Feb 1, 2003)

Crushed coral has both calcium and magnesium.


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## DataGuru (Mar 11, 2005)

If you have a heavy bioload and your water isn't well buffered, it will dissolve when pH drops below 7.5 and increase KH (bicarbonates) and GH (calcium and magnesium). I use crushed oyster shell in my goldie tank.


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## Roger Miller (Jun 19, 2004)

Crushed coral increases KH and GH equally. The GH is almost all calcium. There is some magnesium, but I don't think that crushed coral is a significant source of magnesium. If you need to balance calcium and magnesium then you might need to add a little epson salt.

Dissolving crushed coral or oyster shell consumes CO2. If your tank does not have added CO2 then the dissolution will be slow at best.


Roger Miller


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## sherry (Sep 30, 2005)

I do have co2 as of yesterday.. which is why I wanted the kh up a degree, which is the reason for the crushed coral.

Roger.. I seem to read a lot about people wanting a balance of calcium and magnesium. Do I need to worry about that in a co2 3 watts per gallon tank, or is the magnesium in the cc enough (even if it is less than the amt of calcium)

in other words, do I need to dose a little epson salts with my trace mix? Even better, a couple of years ago almost, when I was first trying to put together this tank -- it has now been up all of two months







... you recommended Dolomite chips instead of crushed coral. Does ANYONE know where to find that stuff? there aren't a lot of gardening supply shops in NYCity


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## Roger Miller (Jun 19, 2004)

> Originally posted by Sherry:
> Roger.. I seem to read a lot about people wanting a balance of calcium and magnesium. Do I need to worry about that in a co2 3 watts per gallon tank, or is the magnesium in the cc enough (even if it is less than the amt of calcium)


My first inclination is to not dose magnesium unless plant growth indicates that they need it. If they need it then the older leaves will turn yellow and corroded, then float off. As it advances, the entire plant may become yellow.

Plants don't use a lot of magnesium. If you do want to add some then you probably only need to add a few ppm. Four ppm will give you about a degree of hardness, and that should be plenty to both balance the calcium and supply the plants.

I can't help much with a dolomite source in NYC. Maybe a trip to the 'burbs? Seachem sells a product called "Onyx" or "Gray Coast Dolomite." I'm not sure that it actually is dolomite, but if you can get a small amount of it then maybe you can give that a try.

Roger


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## sherry (Sep 30, 2005)

I'll let the CC do it's thing. I have to say folks here may have been right about the kh2 being lower than 2.. 

in my ap test, the water stayed clear on first drop and then went slightly yellow. 

now it goes blue on first drop and then bright yellow. 

it is day 2 of cc.. I will let it go another two days and maybe add a little more to give it another boost if I don't hit kh3. 


It may finally be at true kh2.


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## imported_carpguy (Feb 1, 2003)

> Does ANYONE know where to find that stuff? there aren't a lot of gardening supply shops in NYCity


You could check over in the plant district, near FIT in the high 20s between 6th and 7th. 27th, 28th? There's a shop near the corner of 7th on the north side of the street that sells a lot of planting supplies (most the others tend more towards actual plants).

Also try the Compleat Sculptor (212-243-6074) down near the Holland Tunnel on Vandam St. They have a whole basement filled with rocks. They might be able to help you out but maybe I'd call first.


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## sherry (Sep 30, 2005)

I called the three big garden centers in the city .. they all have lime powder no limestone chips under any name. sigh.


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## imported_carpguy (Feb 1, 2003)

Hi Sherry,

I happened to be over in that neck of the woods this morning and, it being Sunday, most of the shops were closed. The one florist I could find thought that Jamali Garden Supply (149 w28th, near 7th 212.244.4025) and NY's Planter Resource & Floral Supply (across the street from Jamali, 212.206.POTS) both carried dolomite chips. Both were closed today.

Have you tried the Chelsea Garden Center (499 10th Ave @ 38th, 212.727.7100)?


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## sherry (Sep 30, 2005)

carp. jsut saw this. thanks for checking adn i'll call the two that were closed.

Chelsea garden center was my first call and they didn't even know what I was talkign about. When I called back and asked for "limestone" chips, they still didn't have it. 

the cc is doing okay. I just figured adding a balance of ca and mg had to be better. 

where in NY are you?


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