Crushed Coral

[Elyse]

Does anyone find their crushed coral raising their pH above 7??? I added some to my aquarium about 1 month ago and the pH has gone from 6 to now floating around 7.3-7.4. I was hoping it would stop at 7 but is this not a thing?

[Ninjoma]

Mine usually levels out around 7.5 with crushed coral. I think it can theoretically go as high as 8.2 if you add enough. 

[Elyse]

@Ninjoma oh I was unaware of this; I have an electric blue acara, rainbowfish, panda corys, panda garra and a blue phantom pleco in this tank. Will they be okay with a ph that high? I was always told that ph of 7 is the best

 

[Ninjoma]

On 2/25/2023 at 10:06 PM, Elyse Douglas said:

@Ninjoma oh I was unaware of this; I have an electric blue acara, rainbowfish, panda corys, panda garra and a blue phantom pleco in this tank. Will they be okay with a ph that high? I was always told that ph of 7 is the best

 

I haven't personally kept any of those fish, but most fish in the trade are pretty adaptable to PH. Your PH of 7.3-7.4 is pretty close to neutral, so I would expect it to be fine for any commonly kept freshwater fish. 

 

[Elyse]

@Ninjoma This was very helpful, thank you!

[nabokovfan87]

On 2/25/2023 at 9:43 PM, Elyse Douglas said:

Does anyone find their crushed coral raising their pH above 7??? I added some to my aquarium about 1 month ago and the pH has gone from 6 to now floating around 7.3-7.4. I was hoping it would stop at 7 but is this not a thing?

There is a long answer to the question....

Essentially think about how stable or unstable your water is.  Let's say from the tap you're at 6.4-6.7 and low or no KH.  Waste or just oxygenation lowers and PH drops to 5.5-6.0.

If you add say 1/2 lb per 10g of crushed coral and then give the tank a few days, maybe your PH will go from 6.4 to 6.8, but you have some KH now that can make it more stable.

If you add 1 lb per 10g of crushed coral and then give the tank a few days to settle, your ph might go in the 7.0-7.2 range.  Once waste happens or a water change you might have the PH drop back down to 6.8 and then slowly rise again over the next couple of weeks.

If you add more, PH would buffer higher, KH would buffer higher, swings should decrease, etc.

Depending on how you set up the coral in the tank you can somewhat control how things go, but you're buffering the tank and there are variables to doing so.  If you add slightly more, slightly less water, then that might change how the buffering impacts the tank.

If you're stocking in the tanks need 6.5-7.0 ph then dose on the lower side and target a specific KH value.  If you're stocking in the tank needs 7.0-7.5 ph then go ahead and lean towards higher KH value.  Eventually, and with testing, you'll be able to regulate things by your KH value and adjust the buffers that way.  CC is designed to be a slow release over time.

On 2/25/2023 at 9:43 PM, Elyse Douglas said:

I was hoping it would stop at 7 but is this not a thing?

What is your KH from the tap and in the tank?

[CT_]

Crushed coral dissolves below a certain ph.   Adding more or less won't change the steady state ph it only changes how fast it'll get there.

I don't have any easy solutions if you're looking for a specific ph though :/.

[Elyse]

@CT_ I just want the pH to stay stable, I’m worried the pH is gonna keep going up and up…

[CT_]

Yeah then you're fine with crushed coral.  Once the water is basic enough the coral won't dissolve and it'll stabilize.  I can't say exactly where because other things effect the details but must people settle out into the 7's

[Flying fox 6523]

On 2/26/2023 at 1:49 AM, nabokovfan87 said:

There is a long answer to the question....

Essentially think about how stable or unstable your water is.  Let's say from the tap you're at 6.4-6.7 and low or no KH.  Waste or just oxygenation lowers and PH drops to 5.5-6.0.

If you add say 1/2 lb per 10g of crushed coral and then give the tank a few days, maybe your PH will go from 6.4 to 6.8, but you have some KH now that can make it more stable.

If you add 1 lb per 10g of crushed coral and then give the tank a few days to settle, your ph might go in the 7.0-7.2 range.  Once waste happens or a water change you might have the PH drop back down to 6.8 and then slowly rise again over the next couple of weeks.

If you add more, PH would buffer higher, KH would buffer higher, swings should decrease, etc.

Depending on how you set up the coral in the tank you can somewhat control how things go, but you're buffering the tank and there are variables to doing so.  If you add slightly more, slightly less water, then that might change how the buffering impacts the tank.

If you're stocking in the tanks need 6.5-7.0 ph then dose on the lower side and target a specific KH value.  If you're stocking in the tank needs 7.0-7.5 ph then go ahead and lean towards higher KH value.  Eventually, and with testing, you'll be able to regulate things by your KH value and adjust the buffers that way.  CC is designed to be a slow release over time.

What is your KH from the tap and in the tank?

I have used crush coral that I have had for a few 
yrs, I've had it in my 3- 55 gal tanks when I had
guppies, got out the guppies then used it in my
goldfish tank, got out of them & I had it stored
in buckets for a  yr, now I'm thinking about using
it in my 75 gal for extra substrate & hard water.

I'll clean it really good B-4 I put it in the tank 
that's goes without saying, but would it be 
worth the work in cleaning it to use again ?

[Biotope Biologist]

What type of rainbowfish? And those fish were fine with lower pH and are quite used to softer water in the wild. The phantom pleco might be the only one finicky with water parameters. 
 

I don’t think you need the crushed coral in the tank for the stock you have. 
 

On 3/4/2023 at 7:05 AM, Flying fox 6523 said:

it in my 75 gal for extra substrate & hard water.

I'll clean it really good B-4 I put it in the tank 
that's goes without saying, but would it be 
worth the work in cleaning it to use again ?

You could but itd be a waste. Id go with blasting sand or pool filter sand. A 25 lb bag can be had at most hardware stores for around $7-10.

[nabokovfan87]

On 3/4/2023 at 7:05 AM, Flying fox 6523 said:

I have used crush coral that I have had for a few 
yrs, I've had it in my 3- 55 gal tanks when I had
guppies, got out the guppies then used it in my
goldfish tank, got out of them & I had it stored
in buckets for a  yr, now I'm thinking about using
it in my 75 gal for extra substrate & hard water.

I'll clean it really good B-4 I put it in the tank 
that's goes without saying, but would it be 
worth the work in cleaning it to use again ?

depending how long you've been running the CC it might already have leached minerals to the point where it doesn't buffer as much as you'd think anymore.

On 3/4/2023 at 9:01 AM, Biotope Biologist said:

A 25 lb bag can be had at most hardware stores for around $7-10.

Here it's $25 per bag before tax or anything.  I think BDBS is fairly affordable, but that has it's own issues. (not a known thing and batches vary based on location where purchased, but that's it's own thing)

Definitely shop around and see what you can find.