Ph Issue - Its Dropped Drastically!

We added a new rock and two new plants to our tank as it was doing very well - and the ph has dropped to the lowest part of the 5.5-7.5 that we have been told is safe. Previously it has sat comfortably enough around 6.8. I am doing a 40% water change this evening after work. I read I can just add baking soda to the water I am adding but want to double check here before doing it and possibly harming my babies. Obviously its the rock causing this and I could remove it - but is it a forever problem if I leave it or just an acidic spike until its sat in there long enough?

 

where did you get the rock? did you clean it? like boiling it in water etc.

 

I would definitely want to know what the rock is, and if it was cleaned properly as the above comment says.

If your water is dropping too rapidly and you haven't added chemicals it might be a good idea of harden your water a little to buffer your Ph levels a little.

In either case you need to remove the rock immediately and see if it stabilizes.

 

The baking soda method does work but it will be a temporary solution. Actually its not a solution in your case since you haven't removed the cause. Adding the baking soda will neutral out the H+ that's leaching from the rock until you pass equilibrium in the balance equation. Then you will be right here right now watching the world wake up from history.


Yeah....dropped a song lyric.

 

Your tap water probably has a very low carbonate hardness (kh) which allows for these ph swings. I have also heard that the baking soda technique works but it is very easy to overdo it and kill your fish. Alternatively a safer way of stabilizing ph is a kh booster that you can buy for shrimp from your lfs. But also here please don't overdo it. Also you really need to keep a very close eye on your ammonia level. The low pH has possibly killed all your nitrifying bacteria and it is not unlikely you will need to re cycle your tank. Make sure you boost your kh and test the kh of your tap water. If your tap water has a normal kh and you have had such a pH swing you have probably not done a water change in quite a while. Then your solution is doing more frequent water changes as decay processes use up carbon in the water, lowering the kh and enabling the enormous pH swings.

 

Some good advice here as well as some risky advice. Step one remove the rock. It may not be the cause bit that is when you saw change. Test your tap water and leave some in a bucket and then test it after it sits 24hrs. You specifically want the pH, kH and gH levels. Soft water can contribute to lower pH but since tap water is between 6.5-8.5 it is most likely not the lead cause.

 

Some good advice here as well as some risky advice. Step one remove the rock. It may not be the cause bit that is when you saw change. Test your tap water and leave some in a bucket and then test it after it sits 24hrs. You specifically want the pH, kH and gH levels. Soft water can contribute to lower pH but since tap water is between 6.5-8.5 it is most likely not the lead cause.

I agree, but isn't it what the whole hobby is about? Taking risks and learning from them?

 

The ph in the tap water does not matter at all since at a low kh level it can just crash from 7.5 to 5.5 in a matter of hours. It just matters in so far that when you do your water change you probably shouldn't change the pH so drastically shocking your fish.

 

Your tap water probably has a very low carbonate hardness (kh) which allows for these ph swings. I have also heard that the baking soda technique works but it is very easy to overdo it and kill your fish. Alternatively a safer way of stabilizing ph is a kh booster that you can buy for shrimp from your lfs. But also here please don't overdo it. Also you really need to keep a very close eye on your ammonia level. The low pH has possibly killed all your nitrifying bacteria and it is not unlikely you will need to re cycle your tank. Make sure you boost your kh and test the kh of your tap water. If your tap water has a normal kh and you have had such a pH swing you have probably not done a water change in quite a while. Then your solution is doing more frequent water changes as decay processes use up carbon in the water, lowering the kh and enabling the enormous pH swings.

#
Ammonia level is safe, we do twice weekly 40% water changes because we have a high load and we have shrimp.

 

Alternatively a safer way of stabilizing ph is a kh booster that you can buy for shrimp from your lfs.

The OP will want to scrutinise the ingredients carefully. Most KH boosters/alkaline buffers (e.g. Seachem Alkaline Buffer) are primarily composed of the same thing: sodium bicarbonate (baking soda).

It isn't an issue if dosed correctly (like any other additive), but some people don't want excess sodium in their tanks, in which case, another solution is to use potassium carbonate which can generally be picked up at LFS specialising in shrimp and some some planted tank stores.

For what it's worth, I've read of many aquarists at planted tank with shrimp using baking soda on a weekly basis (along with their DIY GH booster) with their water changes to elevate their RO water's KH by 3-4 degrees and they haven't indicated an issue: the the sodium concentration otherwise remains quite low if you're only seeking to adjust KH by a few degrees.

 

If your pH is currently below a value of 6, there is essentially no nitrification happening.


When you raise the pH with additives, it is quite possible you will register ammonia. Just a warning. Although, I feel there should still register ammonium as ammonia as per API test if it's present.

If it's a lightly stocked heavily planted tank, the ammonium could be processed directly by the plants.

 

The tank is heavily stocked, I'm told. 120litr tank with 2 cory 6 platy, 6 cold mountain minnow, 4 dannio, 3 tiger barb, a loach, a snail and two shrimp. Before this happened we had had new baby platy and new snail but they have since disappeared...I take a Darwinian approach to this as we really have no room for new fish. but if they survive they deserve to stay sort of thing. This is why we do twice weekly 40% water changes anyway. It is rather heavily planted with over half of the bottom being covered with plants, two large driftwood and a coral-y looking rock so that the fish have places to hide and also to break the current created by the 3 in 1 filter which seems pretty strong! The ammonia to date has never left the safe zone on our in-tank moniter. I have added 1/2 tsp of baking soda to each new bucket today and will keep an eye on it but my concern is what you say about the nitrification - the ph was so low...do you think I will have to cycle again???

I think I did this wrong and quoted rather than replying...ooph! I sure hope this thread makes sense to you folks!

 

When you raise the pH with additives, it is quite possible you will register . Just a warning. Although, I feel there should still register as ammonia as per API test if it's present.

The API test kit assesses for total ammonia (NH3 + NH4+). There is always some presence of free ammonia (NH3) among ammonium (NH4+). At a pH of 6, NH3 comprises 0.056% of total ammonia; at 7.5 pH, 1.77%. A 50:50 ratio between NH3:NH4+ only occurs at ~9.3 pH.

If your is currently below a value of 6, there is essentially no nitrification happening.

This is generally true, although the precise reason why is contested from scientific literature.

Most aquarium resources cite the idea that "low pH = low free ammonia => ammonia-oxidising bacteria can only oxidise free ammonia". This is mostly based on a study conducted by SuzukI et al. (1976).

More recent research from Wett and Rauch (2003) indicates that it's more likely that "low ph = lack of inorganic carbon" which inhibits nitrification; Gieseke et al (2006) also noted that most, if not all, genera/species of AOB have ammonium transporters that allow the oxidation of NH4+.

 

I really suggest you test the ammonia with a liquid test. The monitor might be failing.

When pH is below 6, any ammonia will be in the ammonium form which is much less toxic. As pH is rises the ammonium will convert to ammonia and be toxic to the fish. I feel it's really important for you to make sure there is definitely no ammonia. I suspect there might be some.

The loach most likely got your snails, and any one of your fish could have snacked on the baby platy.

Minnowette Thank you, but I'm afraid that is over my head! But it's it likely the OP has ammonium in the tank that could transform to ammonia as pH rises?

 

Minnowette Thank you, but I'm afraid that is over my head! But it's it likely the OP has ammonium in the tank that could transform to ammonia as pH rises?

That's what I have taken from this, which is also over my head! so I hope we both understood the basic premise

 

Thank you, but I'm afraid that is over my head! But it's it likely the OP has in the tank that could transform to as rises?

Oh it was my fault! I'm not great at explaining chemistry (not being a chemist myself). Let me try from this angle.

Ammonia, when in a solution, exists in an equilibrium in two states, free ammonia (NH3) and ammonium (NH4+):

NH3 + H2o <=> NH4+ + OH-

NH3 and NH4 taken together is commonly referred to as total ammonia.

There is always some amount of NH3 and NH4+ together, but how much NH3 and NH4+ depends on pH and temperature.

For example, at a pH of 7.0 and a temperature of 25 degrees Celsius and 1 ppm of total ammonia, there will be 0.99434 ppm ammonium and 0.00566 ppm free ammonia.

Raising the pH to 8.0 will result in 0.9462 ppm ammonium, and 0.0538 free ammonia (a 9.5 times increase in NH3).

Raising it again to 9.0 will result in 0.637 ppm ammonium and 0.363 ppm free ammonia (a 6.8 times increase in NH3 compared to 8.0 pH).

So you can see that there's no particular number at which all free ammonia changes to ammonium: it's a sliding scale that varies according to pH and, to a lesser extent, temperature.

You are correct that increases in pH will result in ammonium changing to free ammonia.

 

"I really suggest you test the ammonia with a liquid test. The monitor might be failing."

Its brand new and has shown movement - but has stayed in the 'safe' zone so far.

"When pH is below 6, any ammonia will be in the ammonium form which is much less toxic. As pH is rises the ammonium will convert to ammonia and be toxic to the fish. I feel it's really important for you to make sure there is definitely no ammonia. I suspect there might be some."

will the frequent 40% water changes not keep this at bay?

"The loach most likely got your snails, and any one of your fish could have snacked on the baby platy."

I figure the same... like I said though, taking the Darwinian approach..

 

Its brand new and has shown movement - but has stayed in the 'safe' zone so far.

Not sure what to say, I've never had those monitors. I just feel there should be some because nitrification is not happening or at least has taken a hit if the pH is very low. It must be your plants consuming the ammonium which would be pretty amazing.

will the frequent 40% water changes not keep this at bay?

Not necessarily. A 40% water change will decrease ammonia concentration by 40%. If the leftover ammonia after the WC isn't processed, it will still be there with more accumulating by next WC.

I had to mention it because I've already dealt with a similar situation. I couldn't understand why my fish were gulping after a WC with a carbonate hardness of 2. I know why now. And this tank registered 6 or below pH, but before I had plants.

The pH scale is logarithmic, the more alkaline the water, the more toxic it becomes. I suppose that is because technically there will be more free ammonia and less ammonium. Is that right Minnowette?

 

The pH scale is logarithmic, the more alkaline the water, the more toxic it becomes. I suppose that is because technically there will be more free ammonia and less ammonium. Is that right Minnowette?

That's correct. But the effect should be fairly minimal in most tanks because of the very low latent concentrations of total ammonia. For the above example at a pH of 7.0, 1 ppm total ammonia and 0.00566 ppm free ammonia, that concentration of NH3 is very low. As a point of comparison, de Oliveira et al. (2008) tested the toxicity of free ammonia on cardinal tetra, and it took 0.032 ppm for any lethal effects to occur.

Even then, cycled tanks shouldn't have anywhere near 1 ppm total ammonia as a regular occurrence.

 

Hmmmm, this changes my opinion on the amount of Prime needed for converting ammonia. In a tank with a pH of 7, registering 1ppm ammonia, the Prime dosage to convert it to ammonium is actually only for 0.00566ppm free ammonia and not 1ppm of total ammonia.

The 1ml per 1ppm guide is at least reduced the lower the pH.

So I can calculate the amount of free ammonia without buying an ammonia kit that tests free ammonia?

 

So I can calculate the amount of free ammonia without buying an ammonia kit that tests free ammonia?

Very much so! There's plenty of conversion tables floating about on the internet. I've been using this resource published by Florida's Dept of Environmental Protection.

 

some are very usefull while others are just not accurate though, watcout for those.

 

well now its been over 24 hours since the rock was removed and the water changed. All my parameters have returned to normal. I had one fish flashing yesterday, seems to have stopped today. Other than that they all seem content. Definitely going to be more careful about what I add to the tank in future! just have a corner that could do with more in it for our little beauties to hide....