Aquaria Central

[ArkyLady]

I thought I'd report back how my experience with using crushed coral to increase my KH levels worked out.

Test results before adding anything:

12/9/02 -
55 gal: KH 0ppm, GH 50ppm, PH 6.2
10 gal: KH 0ppm, GH 50ppm, PH 6.2

Test results 8 days later with no water changes:

12/17/02 -
55 gal: KH 40ppm, GH 75ppm, PH 6.8
10 gal: KH 40ppm, GH 75ppm, PH 7.2

I added 2 TEAspoons to the 10 gal and 2 TABLEspoons to the 55 gal. I just put the crushed coral down into the toe end of a pair of kneehighs and dropped it down into the filter.

I removed about half of the crushed coral from the 10 gal because I don't want it to go up any higher than it is now. I don't want the 55 gal to get any higher either because the fish in there prefer a lower PH, but I haven't changed the amount of crushed coral in that tank yet.

From what I've read on this topic so far, a KH of 40ppm is still a bit on the low side. However, it's much better than the 0 I had before, so I'm happy with the readings.

I wanted to post the results because in the thread I started before asking how to raise my KH, someone posted that they had 20lbs of crushed coral in their freshwater tank (as substrate I believe). I wanted to give others who are looking at this as a solution to raise KH a general idea of the results they can expect.

I will post again if the next set of tests show any real changes one way or another. If I don't add additional test results or comments to this topic, it is safe to assume that everthing stabalized nicely with the amounts of crushed coral I now have in each tank.

Thanks to everyone who helped with this problem!

[JamisonBWolsh]

Yep.. That was me with the 20lbs in a 20 gallon tank. Raised it from 7.0 to 7.8..no more though. I wish it did though. Sid. petricolas are from Lake Tang (short name) and that ph is around 8.0-9.0.

[wetmanNY]

Thanks for those figures ArkyLady. Those amounts are truly useful to know: 2 teaspoons in 10 gallon filter, 2 tablespoons in a 55. I've cut and pasted your post for use in the revised edition of www.skepticalaquarist.com if that's okay.

[MP]

The figures are useful, indeed, but they're not universal. Everything, mainly, depends on the initial pH. The lower it is, the more prominent changes you'll see. But as it becomes higher, the changes will slow down progressively until they stop.

So, in this respect, Jamison's figures are as valid as yours.

And if your pH is close to 7.8 or so, you can fill the tank with coral and see almost no changes at all.

Now the next set of figures should involve stability of the parameters in connection with water changes. The amount of substrate, its cleanlessness, location, etc. will play a role again depending on the schedule and amount of your water changes. So if you change water frequently and in sizable amounts you may need much more coral to keep those parameters steady (or, in extreme cases, you'll need to prepare water for you changes in advance to avoid sharp fluctuations).

[wetmanNY]

Actually, MP, don't you agree that it's the initial alkalinity ("carbonate hardness") that rules here? The pH just follows passively.

But that's a quibble...

[ArkyLady]

wetmanNY, yes that's fine.

MP, I'm going to do my water change tonite then retest about two hours after and again in the morning to see how much it changes. I'm hoping the change is minor. How much of a PH change does it take in a short period of time (say an hour) to have harmful affects on a fish anyway?

I'm a little nervous about the water change, so will do a very small one this first change and see how that goes.

[JamisonBWolsh]

I know when I do a 50 percent water change on my 20 gallon tank and add 7.0 ph water, it does not lower the ph. The Ph stays at 7.8 and does not decrease to 7.4. I do have 20 pounds of crushed coral and 15 pounds of LACE rock. So maybe thats why it is steady. I would assume only a teaspoon or tablespoon will have DIFFERENT results.

[ctaylor]

I keep crushed coral in 3 of my FW tanks. A 10g, 46g, and 75g. I have about 15lbs in my 46g and 40lbs in my 75g. Not sure how much in my 10g, probably around 5lbs. My water out of my tap is PH 7.6ish and GH 6deg. I have noticed no diffrence in PH and even can drop about .2 lower than my tap. My GH is about 6deg from the tap and the crushed coral raises that to about 11deg.

I initally got it not knowing what it was or it's possible effects on my water quality. My fish did fine and once I figured out what I had done I checked my params. Only change I noticed was the hardness. I have never noticed any negative effects on my fish.

Just my experiance.
Chris

[MP]

Wetman,

pH is what makes the substrate to dissolve and affect the parameters. Naturally, kH and pH are interconnected, but the primary driving force behind the changes is pH of the water.

ArkyLady,

I wouldn't worry too much about pH fluctuation at water changes just yet. The difference between your tap and tank water pH is not dramatic, so just avoid very large water changes (something like 80-90%). Smaller changes (up to 50% or so) shouldn't cause much problems at this point.

Just make sure you understand that if your tap pH=6.0 and your tank is at 8.0, changing 50% of water won't make pH=7.0. It doesn't work this way. The resulting pH will be closer to 8.0 than to 6.0. The buffer is what makes this averaging math not applicable to pH. KH and GH, at the same time, will be affected proportionally (or almost proportionally, for KH).

[mlei30]

I can only get Carib-Sea from LFS. But it's supposed to raise PH to 8.2 from the article I read in internet. Is it too strong for FW tank?

ml