Questions About Ph And Kh

Akasha72

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Hi,

I have a thread currently running about my problems with my PH since changing my substrate to sand.

I'm really confused and I've just been told I need to speak to Bignose.

Bignose, if you are reading this I'm sorry to be a bother but here's what's happened...

I decided to change my soft pebble substrate for Argos play sand. Previously I'd had a fully cycled tank with a steady PH of 6.8/7.0.
Since the change I had a few issue with Ammonia (now sorted thankfully) and my PH fell to about 6 (the test tube is just yellow - using API masterkit)

I decided to lesson the amount of sand I had in the tank as it was about 4 inches deep and I hoped it might help the water but so far the PH is still stubbornly staying at 6.

On Thursday I went to my lfs and had a chat with them and they sold me a small piece of coral rock that they had in a tank with some guppies. It had been in there a while as it had algae on it. They said it had raised the PH in that tank by 1 so by adding it to my tank it should slowly raise my PH back to PH Neutral.

The PH still hasn't moved at all (3 days)

I didn't ask them how long it would take to raise the PH back up so I went to Maidenhead Aquatics this afternoon (different place than where I got the coral from) and the guy there told me to come home, remove the coral and chuck it out as it was going to swing my PH up to 8+ and shock my fish to death.

So far the coral is still in my tank as I quite like it and I also don't know who to believe.

My main reason for wanting to get back to PH Neutral is for my apple snail and my platies. My apple snail has had to go into my 30 litre fry tank (contains old substrate and has a neutral PH) as his shell was turning yukky.

A 30 litre tank is not the best place for a large apple snail.

My sig is up to date. Can you help me?

Thanks in advance

Akasha :)
 
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Akasha72

Akasha72

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done a fairly large water change a couple of hours ago and removed the coral (the warnings were scaring me a bit) and I've just tested the PH and it's now a weak 6.4.

I've also sucked out another half bucket of sand.
 

Rummynose

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I've had low ph problems also, and I added a stocking filled with a handful of crushed coral to my filter in the tank with gravel substrate, it worked like a charm. In my Betta tank, since he has sand as a substrate I added some Aragonite to the sand which worked just as well! :rolleyes:
 
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Akasha72

Akasha72

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well I have this piece of coral rock. Is that the same thing? I've taken it out now though as I'm scared of what it will do. If you can offer me more advice regarding the coral rock then I'm willing to listen

Here's a pic of the rock



It's not a huge lump by any means but I'm getting so many mixed messages about it
 

DrRob

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Coral rock is basically limestone, it will dissolve at a rate dependent on water parameters, flow, temperature and surface area of exposed rock. Things like algae will tend to make it more stable, things rubbing on it will make it less so.

That limestone will eventually make your water harder and stabilise the pH towards 8 ish depending on the exact chemical make up.

However, that's a small piece of rock, with a much lower surface area than coral gravel that people put in filters and isn't in a high flow area, so unless your water is fairly potently acidic or something decides to start trying to eat it, it's unlikely to make a massive difference to your pH.

You'd be better off looking for the buffer that's keeping the pH at 6. I'm guessing your tap water, or whatever water change source you're using, is quite soft as it's not making a lot of difference to the pH.

It may be something as silly as a piece of wood that you've disturbed that is now rubbing on the sand and releasing humic acid and such like into the water keeping the pH down. I can't think of too many sand types that would make the water more acidic by a direct chemical process.
 
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Akasha72

Akasha72

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thanks DrRob, that's helpful. Actually it makes a bit of sense. The large lump of bogwood I have in there initially dropped my normal PH (6.8/7) down to 6.2. Over a period of time my PH began to rise again and the further the wood got into it's leeching process the better the water stats started to look. I think it took about 3 months to get from PH 6.2 back upto 6.8/7

Recently the bog wood has started to break down a little. Bit's keep breaking off it and I keep sucking up tiny bits of bogwood. I'm now wondering if the sand is doing as you suggested and rubbing away at the bog wood and this is why my PH has dropped again.

I suppose the only way to find out would be to remove the bog wood and leave it out over night and see if my PH has risen in the morning.

I'd have to put the wood in water to preserve my java moss so I could test that water aswell in the morning and see if it's gone from PH neutral (my tap water) to PH 6.

That should answer my own questions - yes?
 
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Akasha72

Akasha72

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Hi drobbyb and thanks for that link - which I've just read. I have no idea of my KH and GH values as I don't have test kits for either of these.

I know my water is soft and PH neutral, that's about it really.

So, on to last nights 'experiment'

The storage box containing the bogwood = it's PH has fallen to 6.0 which is what I hoped it might do.

The main tank = it's PH is still at 6.0 which I didn't expect. I expected it to be at maybe 6.4 proving the problem is the bog wood. :huh:


So, today's experiment is as follows - one jug of water straight from the tap with a little de-chlorinator added is sat on the side. I checked the time and in exactly 12 hours (about 9pm tonight) I'll test it's PH. It's PH value now is 7.0 so the de-chlorinator is not the issue (didn't think it was).


A quick question that's come to mind though. With all the rain we've been having could that have affected my water? Is it possible it's coming out of the tap at PH 7 but then settling at PH 6?

I'm hoping today's experiment will answer that but in the meantime are there any thoughts from those of you who understand this?

Sorry if I'm appearing a bit thick - science was my worst subject at school (along with geography & maths!)
 
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Akasha72

Akasha72

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just a quick update:

The water in the jug has increased in PH not decreased. It's now at 7.6

Now I'm even more confused :huh:
 
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Akasha72

Akasha72

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well the plot thickens ... So unbelievably confused and I really don't know what to do.

Today I took my four largest platy fry to my lfs and with a heavy heart I also put my apple snail in the bag.

When I got there they said they couldn't understand why my ph problems should mean I should get rid my snail. They started going on about KH which went straight over my head.

They said they had some stuff (a white powder) that I could add to the tank that would increase my KH and then I could keep my snail (just when I'd accepted he'd have to go)

They tested the water I'd taken him in, which had come out of my fry tank (ph7) and it contained no KH at all. As I don't fully understand this new (to me) KH thing I'm presuming that if the fry tank with a ph of 7 has no KH then there's none in the main tank with a PH of 6 - I kind of grasped that ph and kh are linked :unsure:

So here's what's going through my head.

I want to breed my cories and there's always going to be some platy fry to go in this newly bought fry tank.

Ideally I'd like to change the substrate in the fry tank back to sand for any future cory babies but that could give me a ph crash in there too. As things stand it would make both tanks identical with their water which would mean I can automaticly add any fry without shocking them (as I've done in the past)

BUT ...

if I add this stuff to add KH so Mr Snail can come home (the lfs kept him for now) it will alter the ph aswell therefore messing up the tanks again.

Common sense says contact the lfs and tell them I don't want to add anything more to either of these tank and to let things stay as they are and therefore Mr snail can't come home.


Can anyone help to unravel this as I'm well confused about this whole business
 

DrRob

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Right, KH is carbonate hardness, to put in simple terms it's the amount of bicarb and limescale in your water.

Soft water is low in this, hard water is high in this, hence hard water scaling up your kettle.

Left to its own devices it'll raise the pH of the tank to around 8.4, assuming nothing else is affecting the pH.

Having some in the tank is helpful because it tends to resist allowing the pH to move, hence being called a buffer. Nature is full of them, so you're always going to have a complex mix.

To be honest it's unusual to find a tank with none, unless you're using RO or DI water, or your tap water is ridiculously soft, but soft water is a lot more prone to pH swings, especially if exposed to a calcium source.
 
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Akasha72

Akasha72

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okay, thanks DrRob, so would you add some of this stuff from the lfs (kh buffer) to my tank or would you leave well alone given my stocking?

I'm absolutely lost with this and because I am lost I'm flying blind effectively. I don't want to end up being a victim of bad advice from lfs and waking up one morning to sick and dying fish.

My cories and oto's being the main worries
 
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