Struggling with PH levels in the acidic range of 4 to 4.5

[GailH]

I am having an issue with PH levels in my shrimp tanks that I am scratching my head as to why I cannot fix it. The levels are consistently at 4 to 4.5 - even right after a 50% to 60% water change with water that is PH 8.
Interestingly enough, the nocardia shrimp do not seem to be bothered by the acid water, but it is murdering my snails.
All other water parameters are good to great, it is just this dang PH that keeps staying so low.
I may also have somehow created iron clad shrimp because they are not at all impacted by the huge water changes either.
I stopped putting in Indian almond leaves, since they can lower PH, but I have not removed the cholla wood because 1) the shrimp love it and 2) it makes the tanks look nicer and I really don't want to pull it out and have bland tanks with just floater plants and java moss.
The substrate is mostly sand, with some pebbles.
I run multiple sponge filters per tank.
The impacted tanks are two 5 gallon and one 20 gallon long.
The 20 long is in no way "over crowded" with only about 15 shrimp and maybe 40 rams horn snails (all my mystery snails and most of the rams horns have been killed by the acidic water), the one 5 gallon does have a lot of shrimp, maybe 40, and about 50 rams horn snails; the other only has about 10 shrimp and about 50 rams horns. Snail populations in both 5 gallons are slowly being decimated by the acidic water.
Again, the shrimp do not seem to be impacted at all - they are not acting stressed, they are breeding, eating well - only the snails are getting destroyed. I realize for some, that would be a celebration lol, but I love the snails - pink snails, brown snails, leopard spotted snails, and my mystery/apple snails... which are all gone now.
The plants in the tanks are doing very well - I literally have to clear the frog bit, water spangles, red root floaters and java moss weekly. I can remove everything but a single plant of each of the floaters and the surface will be covered again in about 10 days.
Any ideas what may be going on here? Suggestions for getting the PH back up to at least a 7?
I've never had this issue in all my years keeping fish and shrimp

 

[Magnum Man]

if your base water is an 8, I'd test in a separate container, if your sand is effecting your ph that much... sand could consist of a material, that could be lowering your ph... you could also try removing the driftwood, and adding some limestone slabs...

is your ph test correct (working properly if mechanical, or test kit out of date??? )

I have exactly the opposite problem, with stone hard alkaline water...

 

[seangee]

Try putting some tap water into a glass and testing it after standing for 24 hours. Sometimes the water companies add stuff to temporarily reduce the acidity of water so that it does not corrode the pipes. You may as well do this using 2 glasses - add sand from your tank to one and leave the other just as it comes out of the tap. Check to see if they are still the same - otherwise it is your sand.
What is the KH in your tank? This acts as a pH buffer so if it is low wood, leaves etc will reduce the pH. Like @Magnum Man the water in my taps is incredibly hard (very high KH) and no amount of wood (or even adding acid directly) will bring it down.
FWIW neos are fine with acidic water and frequent changes, but as you have discovered this is not the case for snails.

 

[Colin_T]

What is the General Hardness (GH) and Carbonate Hardness (KH) of the tank water?

What is the pH, GH and KH of the tap water?
To test the pH of tap water, get a glass full of tap water and leave it to stand for 24-48 hours, then test the pH.

Is your test kit working correctly?
Maybe take a sample of tank water to a pet shop and get them to test the pH. Take your test kit too and test the same water at the same time and see if you get the same results.

If the KH (carbonate hardness) is low, the pH can drop. If this is the case, you can add some shells, limestone or dead coral to the tank and it will buffer and raise the pH. You add a small piece of limestone, wait 2 weeks and see how the pH goes. If it's still too low, add another small piece and wait 2 weeks before checking again. Continue adding little bits every few weeks until you get the pH to where you need it.

 

[MaloK]

You will probably need to harden your alkalinity a little.

Cuttlebones are a great supplement for snail, but you still need to harden your KH some more.

Slowly... Until your PH turns around 7-7.5 stable. It really depends on your water source.

I need to maintain 70 ppm KH to have 7.5 PH and my snails are doing great.

That said the cherry shrimps will live in harder KH. But if your adjust the water for snails. You will get molt problems.

So I calculated that 70-80 ppm of carbonate insure the snails are good and it doesn't over harden the shrimps shell.

Most snails would love it between 214-322 ppm. And that means the end of the shrimps.

 

[GailH]

Thank you all for your quick replies.
I have done the tap water test after letting it sit for over 24 hours, so pretty sure that is my actual PH.
My PH test kit is not out of date, and since it appears to accurately reflect the PH of tap water, RO water and other tanks, I'm confident I've got really acidic water in these three shrimp tanks. I am betting it is a combo of the cholla wood and mostly sand substrate, reading the responses here.
My KH is slightly on the lower side, but nothing epic.
I think that Malok said the most important thing here though:

Most snails would love it between 214-322 ppm. And that means the end of the shrimps.

When you get down to it, the shrimp are more important to me in these tanks than the snails. I can keep snails in other tanks with better PH.
One thing that I did not realize is that the shrimp are likely thriving because of the acidic water - it never occurred to me that I never see molt problems in these three tanks because of the acidic water and slightly lower than baseline KH.
You have all given me great ideas though to see if I can get it raised. Much appreciated!

 

[seangee]

Since you mentioned RO water, is that what you are using? I use it in my tanks because of my ridiculously hard tap water, which also has high nitrate.
In my shrimp tank I use Salty Shrimp GH+/ KH+ at the recommended dosage. This raises the GH to 6 dGH and the KH to 3 dKH and keeps the water at a pH of around 7. When I had nerite snails in this tank they did OK - not great but OK, so I never replaced them when they died of old age.
But in another tank where I use pure RO one alder cone or catappa leaf is all it takes to send my pH to 5 or below. I'm OK with this because most of my fish come from very soft water and thrive in these conditions.

 

[MaloK]

PH is irrelevant.. Specifically for invertebrates. Carbonate power is the thing that has to be kept in check.

Even more if your setup are getting older. Shrimp tanks tends to have the lowest water changes imaginable. I can go up to 8 months and more topping only with RO/DI, I need to add carbonates...

But without a precises reading of your GH and KH... It will still remain speculation for us.

Over 40 ppm in KH is enough for cherry shrimps.

 

[MaloK]

Since you mentioned RO water, is that what you are using? I use it in my tanks because of my ridiculously hard tap water, which also has high nitrate.
In my shrimp tank I use Salty Shrimp GH+/ KH+ at the recommended dosage. This raises the GH to 6 dGH and the KH to 3 dKH and keeps the water at a pH of around 7. When I had nerite snails in this tank they did OK - not great but OK, so I never replaced them when they died of old age.
But in another tank where I use pure RO one alder cone or catappa leaf is all it takes to send my pH to 5 or below. I'm OK with this because most of my fish come from very soft water and thrive in these conditions.

If your PH swings because of adding a small botanical. it's too low in alkalinity period.

I have a tank with a PH close to 8 that consumes botanicals like acid.

PH is maintaining stable in the very upper 7. As @seangee, I use RO and Salty shrimps GH/KH+ and still have to add 15 ml of calcium carbonate to reach a de-acidifying level that copes with all botanicals acidifying at each water changes.

In an invertebrate tank removing botanics is removing food. The Good direction come from increasing carbonates consumption.

All lanes, Plants, bacteria, invertebrates will benefit of a suficient carbonate diet.

 

[seangee]

PH is irrelevant.. Specifically for invertebrates. Carbonate power is the thing that has to be kept in check.

Completely right. The actual number is irrelevant but stability is important. You keep it stable by supplementing CaCO3; and I keep it stable with large weekly water changes. Over time the tanks would otherwise become more acidic. The shrimp (applies to fish too) are fine because it happens gradually. If you then do a large change which raises the pH significantly they can go into osmotic shock and die. What is important to me is that if I have to do an emergency 100% change (contamination can happen), the water that I put in is exactly the same as the water I took out; and I don't have to do anything special to make it that way.
This applies even in the 0KH blackwater tank.

 

[GailH]

Since you mentioned RO water, is that what you are using?

I am not using RO water, was only using it to test the accuracy of my test kit (API liquid test kit). However, I am thinking I may need to. I just did another GH / KH test since I did a 50%/60% water change yesterday. My KH is still slightly low, where it was before - 35 ppm, but the GH has gone way up - it is at about 330 to 340 ppm after the water changes. PH is sill at 4/4.5.

 

[GailH]

I just ordered some Texas holey limestone rocks - a dozen in smaller sizes - so I can try adding one per tank, wait, see what happens with PH, add another if needed.

 

[MaloK]

Ok that is some information.. Try your least "precious" Tank with a little more carbonates...

Leave GH as is, from what I'm getting on, it doesn't really matter FOR invertebrates ONLY tanks.

But the harder your GH, is, Higher you KH level will need to be to cope with acidification that lowers your PH.

 

[GailH]

Thank you all again - I'll let you know how it goes

 

[Colin_T]

Most snails don't need hard water but they do need a pH above 7.0 so the acid water doesn't dissolve their shell. The lower the pH the faster the shells dissolve. At a pH of 7.0 or higher the shell should not dissolve regardless of the GH or KH.

What is the GH and KH of your tap water?
Normally if you have a high GH you will also have a high KH.