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Discussion Starter · #1 ·
The normal pH for my tap water is about 6 when I test it with a liquid testing kit.

When I first started my tanks, the pH was up around 7 so I was thinking that maybe some of the fake plants and fake decorations would have increased it.

Fastforward about a month and the pH on both of my tanks is about 5.5 which is pretty low it seems.

I am not sure why it is lower than my tap water and I am not sure what I can do to increase it to about 7ish.

In my one 10G tank I have eco-complete, drift wood. it has quite a few plants (low tech setup) and some fish. In my slightly smaller tank (about 7G), I have MGOPSM with a cap of PFS and then some plants (again low tech and no fish).

Any advice as to what I can do to increase the pH and keep it at a balanced level (if its even possible)?

Thanks in advance for any advice!
 

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Do you do regular big water changes, like once a week or 10 days? If tannins are lowering the pH, that would remove them. I don't think tannins would lower it to 5.5 pH, but maybe it's possible.
 

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Discussion Starter · #3 ·
Would I see be able to see the tannins? The water looks pretty clear.

Even in the tank with no drift wood though the pH is still lower than what my tap water is.

I am not experienced enough with all of this to know what would reduce it. Especially since a lot of my initial tests were around 7.
 

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I recently had a problem with low pH and it seems to have been resolved by crushed coral. My LFS had an open bag in the back they were able to sell me a small amount from.

It comes pretty dusty and you don't have to mix it with your substrate; maybe keep some in a mesh bag or in your filter.
 

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What is the GH and KH of the tap water and tank water?

KH is a measure of carbonates. Carbonates are one of the most common buffers of pH in the aquarium. When carbonates are high, the pH is almost always high. When carbonates are low the pH is more free to vary, and other things in the tank can control the pH.
Organic matter from driftwood, fallen food, fish waste, fallen leaves and other things generally have the result of lowering the pH. If the carbonates are low, then these other things can make the pH low.

Yes, it is possible for organic acids, including tannic acid to lower the pH that much.
Tannic acid itself will usually be seen as a tinting in the water, but there are other organic acids that might not be so noticeable, and any of these, present in even small amounts can lower the pH.

Here is a quick test:

Run a couple of jars of tap water.
Test GH, KH, and pH.
Add baking soda (just a pinch) to one jar, stir well and test again.
Allow both jars to sit out overnight and test again. You might need to stir the baking soda jar again.

a) Pure tap water might have any level of carbon dioxide in it, and allowing it to air out overnight will bring that CO2 into equilibrium with the air. This is the 'control'; what the water will do if you do nothing to it.
b) Adding baking soda is adding carbonates. This should raise the pH. The results should be permanent, but in a quiet jar the baking soda might settle out somewhat if it was not fully dissolved. It would not settle out in an aquarium, there is always some water movement to keep it dissolved. On the other hand several organisms in the aquarium use carbonates, so the level can drop over time, and the carbonates need to be replaced.
You can run the test longer, several days to a week, if you want, or you can vary it by starting with aquarium water and adding baking soda to that.

Anyway, if this test shows you that your water needs carbonates to maintain the pH that you want you then need to figure out how much. The most common way to add carbonates to the aquarium is baking soda (sodium bicarbonate) but some people do not want to add sodium to the tank. You can use potassium bicarbonate (A food item).

Here is one recipe:
1 teaspoon of baking soda, added to a 29 gallon tank, will raise the KH by 2 German degrees of hardness. In my tanks this raises the pH from 'off the chart low' to 6.2.
That recipe can be altered any way you want, any tank size, any amount of change in KH. For example, altering just one factor in the recipe:
Double the tank size = half the change.
Double the dose = double the change.
Combining several changes:
If you want to raise the KH by 4 degrees (double the change) in a 15 gallon tank (half the volume) use 1 teaspoon.
I have used that recipe to figure KH changes for tanks ranging from 10 gallons up to 88 gallons, and KH changes from 2 degrees to 5 degrees.

Do these changes slowly so the fish can adapt. For example, make the KH rise by no more than 2 degrees at any one time. Let them adjust to that for a few days then you can raise it again.
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Other ways to get a similar effect, test these in a jar or bucket:
Add something to the filter that will dissolve slowly, and add minerals to the water.
Coral sand, Oyster shell grit (sold for caged birds like Budgies), limestone gravel or sand and similar materials will do this. Cuttle bone or seashells in the tank or filter will also do this. I use a nylon stocking for the sand sized materials.
These are not really the best treatment by themselves. Every water change would create swings in the mineral levels which are not good for the livestock. I use these materials to keep conditions stable, but when I do water changes I make the new water correct before adding it to the tank. I will add baking soda for KH and GH booster (Calcium and magnesium) to the water for certain tanks, and circulate it until it is well dissolved and the GH and KH test shows the water is correct for that tank. I do not go by the pH. Through the week the organisms that use each of these minerals may use some, but the coral sand etc. in the filter slowly dissolves so the tank stays stable.
 

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Discussion Starter · #7 ·
I recently had a problem with low pH and it seems to have been resolved by crushed coral. My LFS had an open bag in the back they were able to sell me a small amount from.

It comes pretty dusty and you don't have to mix it with your substrate; maybe keep some in a mesh bag or in your filter.
I was thinking of that when I saw some bulk crushed at my LFS as well.

What about water changes? Do you put some crushed coral into a bucket before you put it into your tank to get the level back up? Or the fish are used to the changes?
 

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Discussion Starter · #8 ·
Wow thanks for the reply Diana! That is a lot of info to digest.

I have never tested for KH or GH before. I saw the little test kits for them but never got that detailed with my water.

I will give the little experiment a try. Can I do that and just test the pH or will I need to test KH and GH as well?
 

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The pH test is decent enough, though it is not really measuring the same thing. The GH test is not related, but is a good idea when the water is so soft and acidic. The GH test is measuring the calcium and magnesium. Often, but not always, water will have KH and GH more or less similar to each other. (For sure not always!)
Here is the way I am thinking:
If the pH varies so easily, and is so low...
... then highly likely the KH is low.
If the KH is so low...
... then the GH may also be very low.
This could mean the plants and fish may be lacking for some calcium or magnesium.

Tenuous link, so I would get the GH and KH tests to be sure.
 

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Discussion Starter · #10 ·
If that was the case, would the plants be growing as much as they have been? I have been quite surprised at the growth so far.

And the fish haven't seemed to mind nor have the little snails that seem to be growing in number.
 

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I think a better way to go about this is what kind of fish are you trying to house? A ph of 5-6 isn't necessarily bad if you have fish that are good with it (so most south american fish). My apistogramma I've read likes to breed when it gets down to 4.5 ph, so even lower! I've found it easier to just roll with what you're given rather than trying to change a really important part of your tank: the water. I'd actually be really happy with ph of 5.5-6 so it's all what you're trying to house.

A lot of us here I believe buy stuff like Amazonia substrate and put driftwood just to get our ph at 6. Then adding stuff like c02 makes it go even lower and it's not a problem for the fish as we don't get ones that require ph 7.5+
 

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Discussion Starter · #13 ·
So I was talking to a guy at the LFS and he was telling me that our water is very very soft. It seems to be an issue in this part of North America (he mentioned Seattle and Vancouver as places with the softest water in NA).

So I bought an API GH/KH test kit to see what was going on.

I first tested tap water. KH (water turned yellow immediately) was 1 and GH was also 1 or 17.9 ppm (water turned green immediately).

Then I tested my 7 gallon (approx) tank. It has MGOCPM capped with PFS and a bunch of plants. Again the KH was 1 and the GH was 3 drops or 53.7 ppm. I have no idea why the GH is higher than tap water but ok.

Finally I tested my 10 gallon which has eco-complete, a good size chunk of drift wood, lots of plants and about 8 fish. The KH again was 1 and the GH was 6 drops or 107.4 ppm.

So based on that I know I need to raise the KH. I have read lots of people say that it should be around 5 dKH?!?! To do so it has been recommended that I use some Seachem Alkaline.

What about my GH? I am not sure why it is different but it seems to me that it is at the low end and the high end of what it should be? Or is it ok and I should just focus on KH?

Thanks for any input!!
 
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