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PH keep dropping

5270 Views 18 Replies 5 Participants Last post by  mheat
My low tech tank is fairly new. The substrate is insert sand, so I used only 3 weeks to cycle the tank. Then, I first moved in 2 fire red shrimp to test the tank for a week. Everything was good. I moved in 10 crystal red shrimp 4 weeks ago.

I tested the PH 1 week ago, and found the PH dropped to 5.2 (tap water is 7.4). I added the Seachem Alkaline Buffer to adjust the KH to 1.5 (was 0). The PH jumped from 5.2 to above 7 overnight. Couple days ago, I messaged the PH and it dropped to 6.2. I added the Alkaline Buffer again (half of last time), and the PH went up to 7.4 again. However, 8 hrs later, the PH dropped to 6.8, and keep dropping slowly. It seems that the KH is depleting, and PH is keep dropping. I wonder how can I make my PH stable.

Water parameter is
Tank: 5G (20L)
Filtration: AC30
Nitrate: 0-5 ppm
GH: 5
KH: 0-1 (keep dropping)
PH: ??? (keep dropping)
TDS: 250
Temp: 72 F
Substrate: ADA congo sand, Malaysia driftwood, ADA Manten rock
Plants: java moss, pellia moss, anubias, moss ball
Fert: None, No CO2, No Seachem Excel
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Maybe a coincidence but I have 3 tanks with Malaysian driftwood and 3 tanks with Mopani driftwood. Two Malaysian tanks are bare bottom, one has eco complete. Two of the tanks with Mopani are bare bottom and one has eco complete. All three tanks with the Mopani have stable and relatively high 7.6 ph, the ones with the Malaysian consistently drift down to a yellow reading on the test kit.
Your driftwood is pulling your pH down and you have little buffering capacity.
A recommended way is to add a bag of crushed coral to your filter..

On a side note.. That is a fairly big drop even for driftwood..
Personally I'd pull it and soak for a year or so.. ;) half kidding..
I treated the driftwood before use. I don't see any tea-like color in tank water. The indian almond leaf is also an old one, and no more tannin. If they still release tannin, I hope the PH can hold t bout 6.5-6.8 which is good for CRS. At one time my tank KH was 1.5, but I can't hold it. KH keep dropping cause PH keep dropping too. How to fix this?

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I wonder how can I make my PH stable.
Stop trying to alter it with buffers/chemicals! Best way to keep ph stable is dont try to change it to begin with! Chasing a particular value is usually a lot more difficult than it seems. Its really hard to play chemist and keep everything identical from one week to the next.
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^^^^^ what he said ^^^^^

If you're that concerned you should start taking hard scrape out one at a time and test without the pieces in the tank. You are doing more harm to the shrimp by dumping the buffering chemicals in the tank causing the ph to swing.
Don't think the colored ones are all the compounds that can change things..

lksdriker is correct, but still, adding some coral sand should help.
don't need much AFAICT

Looks like you could even blend some in w/ the substrate..
I add some to all the CO2 injected tanks esp. the one w/ really low Kh. Figure it would help the snails..
Then sit back and enjoy...

Now images on the internet are prone to problems but I have a sensitivity to yellow. You look to have a minor (very minor) tinge, but who knows.
Plants can also drop Kh but you don't seem to have a large enough biomass for this.
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Nice looking tank! Your driftwood and catappa leaves are probably causing the lower pH, even if you don't see tannins. If you are running Purigen, that will pull the tannins while leaving the acid behind.

Personally, I would use an extremely small amount of baking soda (sodium bicarbonate) to raise KH just a bit. The advantage of baking soda over crushed coral are ease of access and better measurability, but either will work.

For the CRS, they prefer very low KH (0-2) and low pH. Your RCS prefer a bit higher GH and pH than CRS, so if you really feel you have to keep both, target whatever you know you can keep stable that is a bit better for both.
I don't add Purigen. I heard just adding coral chip can harm the CRS. I don't mind if the PH can stable at a point whether it is 7.4, 6.8 or 6.2 as long as I don't need to add chemical continuously (Alkaline Buffer). pH swing is harmful to sensitive CRS. The Indian almond leaf can be gone any time, but removing the big driftwood is kind of troublesome. My other fire red shrimp tank has the same tank size (5G) stay at 7.4 pH all the time which is same as the tap water. I can move those 2 male red shrimps to the other tank any time. I concern the CRS first now.

This is my anther fire red shrimp tank which is also low tech without any CO2 or Excel. I does 1/4 of Seachem recommended amount. TDS is about 390, KH is 0, GH is 5, Tmep is 74F, pH is stable at 7.4 (same as tap water). Shrimps breed like crazy.

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Take the rock out and stick it in a bucket of water and test the water after it sits for sometime. Or just leave it all alone and let it settle at whatever ph it wants too.
Possible but..
Still leaning to the driftwood..

Specs for Manten Stones

Type: Igneous Rock
pH: Not Likely to Rise
gH: Not Likely to Rise
kH: Not Likely to Rise
Shrimp Safe: Safe for All
Manten Stones are an igneous rock that are created from the magma of a volcano. These sorts of rocks are typically safe for any type of fauna in an aquarium, but because rocks do get mis-classified all the time, it?s always best to test parameters with your Manten stones before adding them into your aquascape.
Possible but..
Still leaning to the driftwood..
Maybe a combination, not sure and what about the mesh the moss is on. Is it stainless? The driftwood is a definite possibility due to its size Andrew in such a small tank. Only way to find out though is to start taking stuff out.
This manten rock is likely to increase KH. The big driftwood may drop the pH a little. Just wonder how can it bring the tank down to 5.2 at one time.

I have 3 female CRS got berried now. They like to graze on the driftwood. I am afraid to make big changes.
I wouldn't take the driftwood out. CRS prefer lower pH anyway, so let it drop. By adding sodium bicarbonate, you can exactly measure and dose to increase KH to where you want it. The higher the KH, the slower your pH will drop. I think it's dropping quickly due to no KH and the proportion of that wood and leaf to the small amount of water.

I'd shoot for 1 dKH first, see what the resulting pH ends up being, and then add another KH if necessary. Once you figure out where you want to be, you may find you just add like 1/16 tsp of baking soda at each water change to maintain your KH. It's no different than adding fertilizers or GH booster ;)
Would it be the KH and pH to drop is the nitrification itself? The BB acidifies the tank water and the KH is used up, causing the pH to drop steadily.

If I keep adding Seachem Alkaline Buffer in regular base to maintain the KH level (1-2 dKH), will that be harmful to the CRS?
Would it be the KH and pH to drop is the nitrification itself? The BB acidifies the tank water and the KH is used up, causing the pH to drop steadily.

If I keep adding Seachem Alkaline Buffer in regular base to maintain the KH level (1-2 dKH), will that be harmful to the CRS?
The BB growth (and life) is affected by pH, but it does not consume KH or release acid (it does consume some phosphorus though). When you drop below 6.5 pH, Nitrosomonas stops growing, and at below 6 pH, all nitrification becomes limited.

Having never used Seachem's Alkaline buffer, I had to look it up. It's basically really expensive baking soda... Their FAQ confirms it is sodium bicarbonate based.

Ultimately, you'll need to pull various hardscape and test in a bucket or watch the impact on your tank's pH until you figure out the cause. I've also seen a few times where someone's filter was causing issues like this for some unknown reason, but that's the last thing I'd check.
You mentioned the ph of your tap water is 7.4 right? Is that right out of the tap or after it sits approx 24 hours?
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Tap water is 7.1 right out of the tap. After sit for 24 hrs, it becomes 7.4

Now I measure the PH every night about 4 hrs after the photo period. The pH reading drops about 0.1 everyday if I don't do anything (no dosing and no water change).
I find the photo period also affect the PH change. I measure the PH in the morning, it is 6.5. After 7 hrs of photo period, the PH goes up to 6.8. The KH is less than 1 now. KH was 1.5 a week ago, and the carbonate is consumed or depleted somehow.

Still look for a way to stabilize my PH.
I am afraid that crushed coral may raise the KH out of control to my CRS tank. When KH rises, TDS also rises, which is no good to sensitive CRS.

I have this aquavitro carbonate liquid fert. I can does a certain amount to raise exactly 1 dKH into my small shrimp tank. I just don't want to keep using it if I can have a stable PH. I am still look for answer why my KH depletes by itself in a short period of time.

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