How Much Coral

[Amunet]

We just went and got some crushed coral to put into our tanks.. well the filters... to get our pH up.
pH comes out of the tap at 7-7.5, but after it sits in the tanks for a while. It drops to 6. I'm fairly certain it's below 6 though but our test only reads to 6 as the lowest
Anywho!
I was just wondering how much coral we should use in our 28gallon to raise the pH to around 7. I know it's going to take some experimenting but would like an estimate on how much we should use.

Also think it would be ok to put the coral in the filter bags? We always take out the carbon that comes in them so the bags are empty.

 

[BigC]

you need to read a little on the buffering capacity of tap water.
regards
BigC

 

[Amunet]

You're talking about testing for KH and GH and all of that aren't you.
Well let's just say KH is high..... about how much coral would we have to use.

 

[dthoffsett]

You'll defiantely want to use a filter bag. I'd try a few tablespoons to start and just keep an eye on the readings. What is your KH reading, in my case my KH out of the tap is 3-4 and the PH is 8.3, without the coral, my PH drops pretty quickly to around 7.2, is that the same problem you have?

 

[BigC]

I don't think there's a rule of thumb here, it will be a little bit like trial and error initally. Do as the fellow member suggested and use a filter bag adding small amounts each time until you achieve your goal.
Regards
BigC

 

[rdd1952]

As mentioned, it's trial and error but it shouldn't take a lot. For the 28 gallon tank, a good teaspoonful in the filter will probably be enough. You may have to add a little more in a week or so after you see what effect it''s having. Since the tank is empty and cycling, I would suggest doing your experimentation while there aren't any fish in there so you won't have to worry about raising it too much too fast.

The one bad part of the equation is that adding crushed coral raises the buffering capacity of the water which helps keep the pH from dropping or rising. Since your tap pH can be up to 7.5, the crushed coral may end up buffering it to stay there and be higher than you want.

 

[Amunet]

I added about a half cup of coral to a filter bag.
Tested it right after the coral went in... it was at 7.5.
Tested it again later on to give it time to settle in and it went down to about 6.5. I'd be happy with 6.5 if it stayed at that... just anything higher than what it's been at ya know.

KH reading from tap was 2 or 3.. I can't remember (and I just did the test.. SIGH)....
but KH in the tank is only 1.
Yeah out of the tap pH is 7.5, but drops to 6 or below.

Anywho.. I'll leave the amount that's in there for a while and keep testing to finally see where pH settles at and add more iff necessary.

Thanks everyone!

 

[rdd1952]

The results won't be instant. Basically what the coral does is boast the buffering capacity of the water. It will take a few days of the water passing through it for it to really have an effect. How long was it between when you got the 7.5 reading and then the 6.5 reading? Do you have driftwood or something of that nature in your tank that is causing the drop? My tap pH is around 7.2 and my 75 gallon stays pretty close to there even with a piece of driftwood and a KH & GH from the tap of 0. The cycling could also be having an effect on the pH. You might want to try to find some tufa rock. Those should have a little quicker effect.

 

[Amunet]

I tested a few hours after the 7.5 reading. I think I only got that reading though b/c the water was cloudy since apparently I didn't rinse off the coral enough heh.
In the 28 there is a very small piece of bogwood.
But in my other tanks, nothing that would change the pH and all readings are 6 or below.

 

[rdd1952]

Im not sure what's happening. Even if there was no buffering capacity, it should take days for the pH to drop a full point. Have you tried running some tap water and just letting it sit in a bucket for a few days and then testing pH?

 

[dthoffsett]

I didn't even pay attention to the fact that you are cycling your tank. High amounts of ammonia will cause your PH to fluctuate. When I was cycling, mine dropped clear down to 5.5. I'd suggest waiting until your cycle is almost finished, then recheck to see what the PH is. If it is still dropping, the coral should do the trick.

 

[Amunet]

Well the tank should be done cycling soon. Maybe another week or so.
I'll do the tap water test rdd to see if the pH does in fact go down.

 

[Amunet]

Ressurecting this threa to report on tap water test after 2 days of sitting out.
I just did the test on tap water that's been sitting out for 2 days now and it showed a about 7-7.5 reading.

I need to go add a little bit more water to the 28gal... will do another test on it afterwards to see what readings are at then test the next day to see if they drop.
If so, well then I guess it is as what some of you suggested and it's just the ammonia causing the pH to drop