Crushed Corral in a freshwater tank ?

[danos]

I am setting up another tank and am wondering if it is a good idea to put corral in a freshwater tank and what the pros and cons would be?

I am thinking it would look great with the light colors and be easier when vacuuming the tank ?

[carpguy]

It'll drive you pH up and your KH way up. Good for very hardwater fish but not great for most.

There are light medium grained substrates out there if thats the look you want.

[stingray4540]

agreed with carp guy, plus most freshwater fish show better colors with darker substrates.

[Rbishop]

I've heard/believe it will help to buffer, not exactly raise, your Ph at a higher level and increase hardness. Desireable for some freshwater types.

[joephys]

It raises KH, which buffers, and removes CO2 that is in the tank. The CO2 lowers the pH so when it is "buffed" it causes the pH to raise.

[Pufferpoison]

It raises KH, which buffers, and removes CO2 that is in the tank. The CO2 lowers the pH so when it is "buffed" it causes the pH to raise.

thank you, I get tired of telling ppl that it doesn't raise the ph, just keeps it from going down. Great post thanks once again :)

[carpguy]

I get tired of telling ppl that it doesn't raise the ph, just keeps it from going down.
Maybe you should stop telling them that.

I found this at a beer making site (http://www.allaboutbeer.com/homebrew/water3.html) in an article about water chemistry:


Bicarbonate or carbonate. May be expressed as "alkalinity" or "temporary hardness" in water reports. Strong alkaline buffer which raises pH. Contributes a harsh, bitter flavor in combination with hops. Also promotes the extraction of tannins from grains and hops and leads to darker colored beers.
…
Water is generally close to 7, or neutral. The most common deviation is to the alkaline side where high carbonate content can push water pH as high as 8.5.


I used that cite since it was the first I could find that had a top number. My water is soft and acidic, so I haven't spent too much time working the top end. I'll try to find some back up for it, but I'm on my way out the door.

If you add crushed coral your pH will go up. If you add a lot it will go up quite a bit.

[justintoxicated]

In my experience it only buffers the water, when I trippled the amount in my filter PH only went up slightly to about 7.2 from 7. I think it can only disolve so fast, the sofer your water the faster it disolves, the harder your water the slower it disolves, when it disolves it makes your water harder and that is why it works as a buffer. Don't forget that crushed coral is not strickly bicarbonate it is calcium bicarbonate.

In takes with a high PH / Hardness crushed coral will likely do nothing at all!

[Rbishop]

True....but if coupled with regular water changes, of a lower pH you do not see the total net affect of the pH rise. If you loaded a 50 gal tank half full of crushed coral and added 7.0 water and let it sit for an indefinite long time, you would see a large pH rise as the dissolving continued. With all the variables in a "living" tank, (feeding,respiration,degassing,plants,filtering,cl eaning..), one can only make an arguement for a snapshot in time against objective cicrcumstances. Kind of like statistics...you can make the numbers prove anything under a given set of theories and if you ***-UME a whole bunch of others. Get over it....it buffers or minimizes net changes in pH in a constantly changing enviorenment...raise it in stable ones....move on....

ENJOY THE FISH!

[carpguy]

In my experience it only buffers the water, when I trippled the amount in my filter PH only went up slightly to about 7.2 from 7.

So in your experience using a small amount led to a small increase in pH. I put 6 tablespoons in my filter and my pH went from 6.2 to 7.0. My KH went from 1 dKH to 4 dKH.

The impact will vary according to what the pH and KH are to begin with. How much calcium carbonate is used will also make a difference.

The original poster was asking about using it as a substrate. Its popular in rift tanks. You don't see it very often (freshwater-wise) outside of that.

[Roan Art]

In my brackish tank I used crushed coral as the substrate and the pH went from 7.4 to 8.1 in two weeks.

That's about normal for a high pH dissolve rate with crushed coral.

Roan

[justintoxicated]

I'm using it in my mini Brackish water tank for substrate as well.

When my PH whent from 7 to 7.2 in my community tank this was filling up one of the bins with crushed coral in my Fluval 204, previously had enough crushed coral to fill up a whisper 10i. the 10i was able to raise my PH to 7.0 with the small amount of crushed coral it just took alot longer (a couple weeks). There was alot more flow and surface area exposed when I moved it to the fluval and the PH went up alot faster. In fact I need to check it again :)