pH and KH issues (Safe T Sorb)

[Gideyon]

I'm having problems. 

Brief history:

This 10g used to home a betta at 75 F, pH 7.2, KH 40.  The water always came from the tap. 

After he died, I tore down the tank. Bleached. Rinsed. Sun dried. 

Now I'm putting in a new substrate of baked clay (safe t sorb), with a little bit of laterite.   Two small dragon stones. 

Water came from the garden hose. 

After a few days of getting rid of the finer particles of the clay, I added prime and a few hours later, I tested the water. 70 F. KH 0, pH 6, and there was about 0.5ppm ammonia, 5-10ppm nitrates. 

I did a water change, removing water down to the substrate level.  Replaced with tap water. 

Ammonia is just a fraction above 0 (small tint of green that is lighter than the chart).  Nitrates 5-10ppm.  pH 7.2.  KH 40.

A couple of hours later, pH dropping. 

An hour after that, pH still dropping, now around 6.5. KH is still 40.

What could be altering the pH?   pH out of the tap is 7.2, but I haven't done a test after a few hours of sitting.  The substrate shouldn't do this.  The stones shouldn't.  I wouldn't think laterite would. 

Could the water supply have changed that much?   The nitrates are present in the tap as well at the same levels. That wasn't the case back in February when I was setting up the tank for the betta. I was getting 0 nitrates at the beginning. 

Why would KH be 0 in one test and back to 40 the next?  Faulty test, or can KH be altered? 

Any suggestions?   I'm not sure I can cycle the tank with the pH that low. 

Edited August 14, 2021 by Gideyon

[Gideyon]

Also. The ammonia is a mystery, but I'm thinking maybe a bug got into the substrate as I was rinsing it. 

[Biotope Biologist]

You don't have enough kH to buffer the pH. 40 ppm is on the lower side and is getting used up to form carbonic acid. Thus why your pH is low. Test your gH, if that is low too you can use crushed coral if it isn't low you will have to buy carbonate salts. Seachem sells a version of this called alkaline buffer. KH serves to buffer pH from having crazy swings.

[Gideyon]

On 8/13/2021 at 5:36 PM, Biotope Biologist said:

You don't have enough kH to buffer the pH. 40 ppm is on the lower side and is getting used up to form carbonic acid. Thus why your pH is low. Test your gH, if that is low too you can use crushed coral if it isn't low you will have to buy carbonate salts. Seachem sells a version of this called alkaline buffer. KH serves to buffer pH from having crazy swings.

GH is between 120 and 180. I'm not good with color shades. Maybe closer to 120. 

Do you know what could be lowering it? 

[Biotope Biologist]

Well nothing you stated in your post is calling out to me. Did you have issues with your tap with the betta? Clay and laterite are both inert substances. 

 

It could be a multitude of causes ranging from tap water additives to simple gas exchange. I wouldn't even know where to begin.

 

[Gideyon]

I'm reading that nitrates can eat away at KH.  I'm not sure if that's what's happening. 

I'm going to recheck my ammonia tomorrow.  If that goes up, then there's some kind of ammonia source in the tank.  Which would be a greater mystery.  But maybe that's also affecting the already low KH? 

I did see foam like bubbles come to the top when I added water the first time. Maybe those were caused by protein / something dead in the tank. I didn't see it after my water change.

When my betta was sick, the pH was still 7.2.   But nitrates were higher at that time. 

I'm going to try another test by leaving tap water in the vile over night and test  the pH in the morning.   If it's in the 6s, then it's not the tank.  If it's not, it's the tank 

Does temperature affect kh and pH in anyway?  With the betta, I had it warm. Now it's cool.   

[CT_]

Clay is pretty porous dissolved solids could maybe adsorb for a while.  On the same note it could be releasing something that was trapped.

 

Also if your tap is low CO2 then letting it sit would lower the pH.  I don't think nitrite itself lowers the pH but converting ammonia to nitrite releases acid.

 

I'd just let it sit for a few days changing water until it looks good.  And or you could add crushed coral, which is probably a good idea any way.

[Gideyon]

Now my tank is looking like it has tannins in it.  🤦

[Gideyon]

I appreciate both of your feedback. I'm just going to run the filter with a carbon cartridge for a while.  I need the weekend off from my stress relieving hobby. 

[Hobbit]

Sometimes this hobby is so stressful! Let us know what the pH of the vial looks like after it sits overnight. 👍

[ArchwayAquatics]

I'm curious, did you add fritz once, or after the water change as well? My thought is that the pH change could be a reaction to the removal of chloramines from the tap water. Even if your water treatment plant uses chlorine and not chloramines, they would be able to form from the free chlorine and nitrates in the water. When treated this would dump the locked nitrogen back into a free form. Keep in mind I'm a terrible chemist. If someone way better at that part of science cares to correct me please do. 

[Gideyon]

On 8/13/2021 at 9:22 PM, ArchwayAquatics said:

I'm curious, did you add fritz once, or after the water change as well?

Prime. 

I normally only tested a week after a water change.  Maybe this was happening and it got back to normal by the time I tested?   Although that kind of ph fluctuation can't be good for the fish.  

[Gideyon]

Morning after.... 

The tap water I left out over night, it still appears to be 7.2.  I checked the tank, it looks to be 6.5.   Tint of green.  If it's still 6.5 tomorrow, maybe it's stabilizing. I'll do another big water change and see. 

I put in a carbon cartridge last night and it's clearing out whatever that brownish color was.    I have no idea what the cause of that was.   I'll keep it running.   It's clear something in the tank is causing the drop now.   It's just a matter of figuring out what.  Maybe the carbon filter will get rid of the culprit. 

 

 

Edited August 14, 2021 by Gideyon

[Gideyon]

Should I have boiled the rocks before placing it in?  I just did a rinse. For some reason I feel like rocks will explode if I boiled it.  No scientific reason.  Just a strange "fear"

Im wondering if something in the dragon stone crevices that wasn't washed away is doing this. 

[Tami]

I am no professional but over my first year and a half I have learned that patience is key - if you keep messing with it you will never figure out what worked or was wrong.

If you don't have fish in there, then just let it sit with your filter running and lights as you want them and wait.

Frequent water changes and disrupt a lot of things - plus your source water could have minor differences every time you change it unless you are using  0 TDS RO/DI water

Test once a day and keep a journal.

When I had crazy readings it was an inert cause (once never figured it out) or my source water all the other times.  Switching to RO/DI has fixed that for me - the cost was worth it since I was buying bottled water.  If you are using your tap and it is the cause you can figure out how to adjust your tap water for stable numbers.

In my experience nitrates don't affect my pH - my nitrates are 15-60 without my pH changing.  My RO/DI water goes in at 8 (the tank test 7.8 after) and settles at 7.2 in 24 hours without a change until I change water again in 1 week. GH/KH can affect pH. figuring out if that is stable would be helpful.

Good luck and breath - if there are no lives at stake  - you have time to learn patience

 

[Hobbit]

Ohhh I bet I know what’s happening. The same thing happens in my tanks where I use Fluval Stratum.

Some of these clay substrates can actually absorb carbonate (buffer) out of the water. This lowers your KH and pH quite a bit. It sounds like others have had this experience with Safe T Sorb:

https://www.aquariumforum.com/threads/safe-t-sorb-and-ph.41051/

Eventually, the substrate will get saturated with carbonate and your KH/pH will go up again.

My understanding is that the absorbed carbonate in the substrate will still prevent pH swings, but maybe @Mmiller2001 knows more about that (he uses CO2 and has high tech planted tanks).

When this was first happening to me I was SOO confused until I saw someone make an off handed comment about how Fluval stratum absorbs carbonate. It’s not a bad thing—it’s how they’re intended to work. But it is rather unnerving. I’m not sure I like it. 😅

[Mmiller2001]

On 8/14/2021 at 11:26 AM, Hobbit said:

Ohhh I bet I know what’s happening. The same thing happens in my tanks where I use Fluval Stratum.

Some of these clay substrates can actually absorb carbonate (buffer) out of the water. This lowers your KH and pH quite a bit. It sounds like others have had this experience with Safe T Sorb:

https://www.aquariumforum.com/threads/safe-t-sorb-and-ph.41051/

Eventually, the substrate will get saturated with carbonate and your KH/pH will go up again.

My understanding is that the absorbed carbonate in the substrate will still prevent pH swings, but maybe @Mmiller2001 knows more about that (he uses CO2 and has high tech planted tanks).

When this was first happening to me I was SOO confused until I saw someone make an off handed comment about how Fluval stratum absorbs carbonate. It’s not a bad thing—it’s how they’re intended to work. But it is rather unnerving. I’m not sure I like it. 😅

I completely forgot about that, I think you are correct!

[Gideyon]

On 8/14/2021 at 1:26 PM, Hobbit said:

Ohhh I bet I know what’s happening. The same thing happens in my tanks where I use Fluval Stratum.

Some of these clay substrates can actually absorb carbonate (buffer) out of the water. This lowers your KH and pH quite a bit. It sounds like others have had this experience with Safe T Sorb:

https://www.aquariumforum.com/threads/safe-t-sorb-and-ph.41051/

Eventually, the substrate will get saturated with carbonate and your KH/pH will go up again.

My understanding is that the absorbed carbonate in the substrate will still prevent pH swings, but maybe @Mmiller2001 knows more about that (he uses CO2 and has high tech planted tanks).

When this was first happening to me I was SOO confused until I saw someone make an off handed comment about how Fluval stratum absorbs carbonate. It’s not a bad thing—it’s how they’re intended to work. But it is rather unnerving. I’m not sure I like it. 😅

Fascinating.... 

 

This makes sense.  Maybe that's why my tank pH was slightly higher (but still low) after the water change than my first test before.     I'll let this sit until Monday and check.    If it's still 6.5, maybe it's all absorbed, and I can put fresh water in it. 

Edited August 14, 2021 by Gideyon

[Gideyon]

Monday morning... KH is 0 again, pH bottomed out. 

I'll try another water change and wait it out again.

There appears to be an ammonia source in here that I can't figure out. Although at this low a pH it's likely all ammonium.  

 

I removed the carbon cartridge this morning also. I'll see if that brown color comes back. 

I didn't want to get crushed coral because I didn't want to buy 10-15 lbs of it. Until I discovered the only 1lb option I've seen at aquarium co-op.   That'll come in some time this week.  I might try a little and see how that goes. 

 

 

Edited August 16, 2021 by Gideyon

[Gideyon]

It crashed yet again two days later. I guess this kh drop isn't slowing down.    Crushed coral comes in today I hope.  I'll see if that gives me a little more stability with kh/ph.

Maybe it's because I have 3"of STS it's taking longer....  

[Hobbit]

Ooof that’s a lot of safe t sorb. You might be at this for a while… Does the pH get lower than 6.5? If it stays at 6.5 you may be fine. I’m keeping a bunch of medaka at 6.4 (not on purpose—my water’s just really soft) and they’re doing great. I’m sure plenty of fish would be happy in 6.5 water.

[eatyourpeas]

I think @Hobbit has pointed to the potential cause. My experience with Fluval Stratum was similar, but I only had 1.5" of substrate in the tank. Your thick layer may take a little bit longer to stabilize.

I successfully used Seachem Alkaline Buffer to raise the KH. I dosed slowly. Plants started to show happy faces.

My Ohko Dragon rocks had a large amount of sediment inside crevices I could not see. You'll eventually see these sediments drop onto the substrate. I do not think boiling them would have taken care of that since they sit on shores for years and accumulate this mudlike clay.

Since then (not suggesting, just saying what I did) I have redone the tanks and decided to go for a sand substrate, and much thinner to avoid anaerobic pockets. My Fluval tanks lasted a little over a year and were great for shrimp. I did not enjoy how light it was and difficult to anchor the plants, and it went everywhere when easily disturbed.

I preferred heavily planted tanks, so the sand has worked much better and I do not vacuum the substrate anymore.

I hope you get yours to stabilize soon. It is a game of patience. 🙃

Edited August 18, 2021 by eatyourpeas

[Gideyon]

On 8/18/2021 at 10:46 AM, Hobbit said:

Ooof that’s a lot of safe t sorb. You might be at this for a while… Does the pH get lower than 6.5? If it stays at 6.5 you may be fine. I’m keeping a bunch of medaka at 6.4 (not on purpose—my water’s just really soft) and they’re doing great. I’m sure plenty of fish would be happy in 6.5 water.

It bottomed out.  It might even be lower than 6.

My theory/hope is that if I can get the water flowing through the crushed coral, it'll speed up the rise in KH, but also speed up the absorption of carbonate in the substrate.  

[Gideyon]

I got the crushed coral, along with the api GH and KH test kit.   I placed the crushed coral in a plen plax bubbler (which is essentially a box filter). I used a T-connector from my airpump, but air is only going to the bubbler, and not my airstone.  Maybe the pump isn't strong enough? 

Anyway.... I'll see how this goes. 

This liquid test - how is this not the most ridiculous type of testing?   The strips were so much easier.  How do you intend to put a drop, cap, shake, uncap, drop, cap, repeat until it goes from one color to the next?   After one drop it was already yellow.  What?     The strips still indicates 40 after the water change.  Am I doing something wrong?    

Anyway... After the water change, adding the coral (but it wasn't long enough to do anything), pH is back to 7.2ish, and the KH according to the strip is 40.   

I'll check again in the morning. 

[Patrick_G]

Here’s a paper on the properties  of laterite. I have a hunch it’s pulling your ph down. I’m sure there are other factors in this situation but I’m thinking the laterite is doing the heavy lifting. 
https://www.hindawi.com/journals/tswj/2014/247194/