Crushed coral

[esoxlucius]

This is just a heads up really for those of you who have water with a very low buffering capacity, and have the need to used crushed coral just to keep your PH from dropping too much.

I have a bag of crushed coral in my crate tier system on my 360. It's in the part with my bio media so it very rarely gets disturbed. It's been in there for as long as my 360's been running, about 18 months.

I knew eventually it would need replacing as it slowly breaks down but I didn't realise the extent or rate that this break down actually happens. At water change time my PH has been slowly dropping to the yellowy colour on the chart, around 6.0. That's not too bad but I prefer it to be around the 7.0 mark.

So this morning, for the first time, i delved into my bio media section and the picture below shows what's left of what was once around 2kg of crushed coral. The cut down stocking which I used to house it, and no it doesn't have any holes in, and yes it was tied up securely, was virtually EMPTY.

So the message is, if you use crushed coral, but it's in a place in your system out of the way, just bear in mind it will "disappear" eventually and could leave you with lower and lower PH.

 

[TwoHedWlf]

Interesting. I use coral fingers in mine. I don't really notice much degradation in the pieces. And one piece is the skeleton of a brain coral that died in my marine tank some 10+ years ago.

 

[A201]

Maybe fill the media bag w/ small limestone rocks?
Probably wouldn't break down so quickly.

 

[esoxlucius]

Maybe fill the media bag w/ small limestone rocks?
Probably wouldn't break down so quickly.

Bigger chunks for sure would help. I've thought about my situation a little more and my bag of crushed coral is in a trickle tier system. So rather than it being sat in water relatively undisturbed, it constantly has water trickling over it, which of course is going to speed the erosion up.

I'm going to reposition my bag. We live and learn everyday, lol.

 

[jjohnwm]

That's an eye opener. Interesting.

I'm assuming that your low-pH source water is increasing the speed at which the coral dissolves. If your source water were neutral or basic, the coral would last much longer...but of course, you wouldn't really need to use it then at all.

I am forever thankful for my good fortune to have a well with clean, neutral water that requires no fiddling. Lots of water changing keeps my tanks at the same level. If I had to fret about making RO, buffering my pH or neutralizing chlorine/chloramine...I wonder if my fascination with aquariums would ever have taken hold in the first place.

 

[esoxlucius]

That's an eye opener. Interesting.

I'm assuming that your low-pH source water is increasing the speed at which the coral dissolves. If your source water were neutral or basic, the coral would last much longer...but of course, you wouldn't really need to use it then at all.

I am forever thankful for my good fortune to have a well with clean, neutral water that requires no fiddling. Lots of water changing keeps my tanks at the same level. If I had to fret about making RO, buffering my pH or neutralizing chlorine/chloramine...I wonder if my fascination with aquariums would ever have taken hold in the first place.

The actual PH of my tap water is very good, around 6.8. But it has zero buffering capacity, my GH and KH levels are pants. So of course in a tank with a heavy bio load the PH drops pretty quick, hence the need to slow it down with crushed coral. And yeah, the buffering nature of the coral is forever fighting the acidity, and there's only one winner in that competition!

I also have a bag of crushed coral in the sump of my 180g but the bio load isn't as heavy in that tank plus the bag of coral is in an area of the sump where the flow is slow. Unsurprisingly that bag lasts quite a long time.

It's not the lower PH doing damage to my fish that concerns me, my fish are, or seem, fine. it's the effect it has on the maximum reproduction of BB that worries me. I'd rather try and stay firmly in the "goldilocks" zone of PH so that I maximise the ability for my BB to flourish. Too high or too low and the numbers change. In a tank with a high bio load I doubt any good would come from BB production being hindered.

That's how I look at it anyway.