pH less than 6 - digital pH monitors

Hi all,

After buying some fish yesterday, acclimatising them for 1.5 hours and finding them all dead this morning I was most upset. After some maintenance today and a full set of test results, I have a pH lower than my API test kit will read (6) and a very low KH. All other readings are fine including ammonia, nitrite, nitrate and GH.

I have attempted to address this by adding some crushed oyster shell in the filter try and raise both KH and pH. I would also like to monitor my pH more closely.

Does anyone use a digital pH monitor? Are they any good? Any recommendations?

Thanks,

Dan

I bought one of these which have worked very well:

http://www.amazon.co.uk/gp/product/B001GZ0O2W

But they are a bit expensive, you could potentially buy a PH Controller for just a little bit more. There might be some very simple color strips you can get for a lot less in your local fish shop. Basically a strip you put inside the tank that changes colour depending on PH value. Never used one though so not sure how well they work.

There is no way your fish were killed by low pH, however there might be something in the water that is toxic and which also drives the pH down. This is an important distinction and you need to do a better job troubleshooting the cause of death. Adding oyster shells is a knee jerk reaction and serves no purpose.

Cheers,

Hi. What fish did you add to your tank?

I added 20 corys to my 350L tank, not quite adults yet. I already have about 8 in there which seem fairly happy.

If it wasn't the low pH I don't know what the cause was. All of the test results were fine apart from pH and KH. Adding the oyster shell was discussed in another thread on here, I was going to do this anyway. I am open to suggestions for other causes.

The pH meter linked seems quite pricey. Are they all about £50?

Cheers,

Dan

20 corys in one hit
Possible ammonia spike?
I've got a 500 ltr and I would only add maybe 5 at a time dependant on fish type
Matt


Sent from my iPhone using Tapatalk

It is possible, but it must of been one hell of an ammonia spike to kill all of them. Is the tank a new setup? There must be something quite badly gone wrong for all of them to die in 24 hours.

drooke said:

...If it wasn't the low pH I don't know what the cause was...

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FYI, Corydoras are native to South America and they prefer soft acidic waters but are found in a wide variety of waters and that's why they are widely distributed. What they have low tolerance for is salt. Is your water soft because it's the output from a salt based water softener? Did you throw a lot of food in the tank to feed them possibly? Dirty water due to poor husbandry will kill fish, not low pH/KH, especially fish that are from low pH/KH waters, so you really need to look elsewhere for faults in the tank. What was your water change schedule? Were you using CO2 or Liquid Carbon? We need more data about the tank before we can draw any conclusions. Panicking about pH/KH is exactly the wrong approach. If there is some toxic agent driving down the pH then you have to find the source of the toxic agent. Were you adding any other products to the tank? Have you installed wood or other hardscape that is not compatible with aquatic life? These areas are where you need to investigate.

Cheers,

Hi Dan
Ive heard this before....young cory's dieing soon after transferring into another set up.
Where did you buy them from?
Was the water in the bag similar to your aquarium parameters?
Under 6pH is low? Do you use RO water?
hoggie

Hi all,
First up I'm very sorry for your loss, but you need to know some other details before you can make any sense of a pH reading.

Parameters
The parameter you really need to know is the conductivity of the water, and the other parameter that would be most useful is the carbonate (dKH) buffering, particularly as you say that your test strip read "very low dKH".

pH meter
An electronic pH meter is a useful acquisition and the one in the link looks a good one for the money (I certainly wouldn't buy a cheaper model than this), but these aren't meters that you can just dip in and get a reading, they need calibrating with pH4 and PH7 buffers before every use, and the reference electrodes need to be stored in the correct manner to avoid damage to the membrane.

pH measurement
Because pH is measured on a log scale, and uses the ratio of H+ to OH- ions as a proxy for the acidity/alkalinity of a solution, not all pH readings mean the same thing. This is why I would like to know the conductivity of the water, if this value is below about 100 microS, pH is pretty meaningless.

Adding the oyster shell was discussed in another thread on here, I was going to do this anyway. I am open to suggestions for other causes.

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Oyster Shell Grit
I probably suggested the "Oyster Shell Grit", it is the aragonite form of CaCO3, which makes it more soluble than the calcite form, and it is a cheap and easy way of adding some dKH/GH to your water. We may want to do this if we think that the lack of carbonate ions may cause problems with the CO2/carbonate equilibrium. However we know that carbonic acid (http://en.wikipedia.org/wiki/Carbonic_acid) is a weak acid, and that the changes it causes in pH are not the same as changes in pH in a buffered system.

What killed your fish?
Having said all that I would be absolutely amazed if this was a pH effect. If you add CO2 I would be fairly happy they've suffocated, and if you don't I would expect that it is related to lack of O2 reaching the filter media, due to the higher bioload. You said they died over-night, and that would strongly suggest it is a O2/CO2 ratio problem.

Level of planting
Some measure of how heavily planted the tank is would be useful. If the tank is very heavily planted the likely cause of the fish suffocating is that the extra bio-load meant that the exchange of gases through the gas exchange surface was inadequate, and CO2 built up to levels which proved terminal whilst the plants were respiring, but not photosynthesising, due to the O2/CO2 ratio and Bohr effect.

If the tank is lightly planted, the filter media became oxygen depleted due to the extra ammonia produced by larger bio-load, because the conversion of NH3 to N02 to NO3 is an oxygen intensive process. It also utilises carbonates, in this case the low dKH measurement may be an indicator of this problem. The reason this doesn't happen in more heavily planted tanks is that the plants preferentially take up NH3 and it doesn't end up in the filter.

Test Kits

All other readings are fine including ammonia, nitrite, nitrate and GH.

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You honestly don't gain anything useful from these tests, to accurately measure these parameters you need lab. grade kit that needs frequent re-calibration and then you need to analyse and prepare your samples using appropriate protocols.

I've got access to lab. kit with ion selective electrodes, an atomic absorption spectrophotometer and both GC/HPLC and I still wouldn't know what had killed the fish in the same situation by using analytical means.

Hope that makes sense, cheers Darrel

Hi all,

Thanks for all the replies. I am very gutted to have lost all of the new additions and I'd love to get to the bottom of it to avoid the same in future.

Some more background for the tank:
* Water: De-chlorinated tap water, at tap pH of 7
* 350L
* Filter/powerhead: Eheim 2128/Hydor Nano 900l/h
* Heater: 300W Rena
* Temperature: 26 - 27 celsius
* Substrate: 10L Tropica Plant Substrate topped with approx. 45KG play sand from Argos
* CO2: None
* Plants: About 6-7 established Amazon swords, 3 Anubias, some small crypts, a selection of floating plants (Pistia, Limnobium & Salvinia about 15 plants in total)
* Fertiliser: TPN+ 15ml twice a week
* Fish: 3 large angels, 3 dwarf neon rainbows, 2 neon tetras, 2 lemon tetras, 4 sterbai corys, 4 albino corys

The test kits I've used are all supplied by API. The KH test is basically add test fluid to a sample of water and count the drops until water turns from blue to 'bright yellow' with 1 drop = 1dKH. The water was a pale yellow after the first drop, and got brighter with more. So difficult to determine the actual value.

The fish came from a breeder who was also keeping discus, angels, corys and their fry - I have no reason to doubt the quality of the fish. The corys were kept in pH of 7 at about 27 celsius. I picked the fish up at about 17.00 on Saturday, transported them home in the car driving carefully and wrapped up to insulate. The bag was placed in the tank for 15 minutes at about 18.20, then opened and started introducing tank water roughly every 10 minutes. Continued this until about 21.20 at which point I netted them out of the bag into the tank. In the morning at about 07.30 the majority of corys had died with about 3 hanging on. The last one died after the maintenance and water change about 13.00. I've not lost any other fish since introducing the corys. None of the fish were gasping for air on the Sunday morning, and the test results I've mentioned were taken during the maintenance.

For a digital pH meter, I was hoping for a simple meter similar to a digital thermometer. It sounds like I may not be able to get such a thing. I'd definitely have trouble calibrating one.

The suggestion of salt causing the issue could be a possibility with the play sand perhaps. Although, surely it would affect the other fish the same?

Any further help appreciated.

Dan

Hi all,
The tank set up makes this all sound more and more mysterious, but I have just had another thought, and it is a specifically Corydoras related one. "Coryman" in this thread is Ian Fuller <http://www.planetcatfish.com/forum/viewtopic.php?p=90914> so his mention of "self-poisoning" carries a lot of weight.

The bag was placed in the tank for 15 minutes at about 18.20, then opened and started introducing tank water roughly every 10 minutes. Continued this until about 21.20 at which point I netted them out of the bag into the tank.

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I must admit I never acclimatise my fish, as long as the temperature in the bag and the tank aren't too different I aim to get the fish out of the bag and into the tank as quickly as possible. I also don't worry about the water in the bag ending up in the tank.

My usual method is to turn the light off, open the bag whilst it is floating, and then submerge the neck of the bag and let the fish swim out of their own accord. I've done this with "delicate" fish as well as more hardy ones . I've never had any problem with this, although I realise it goes against nearly all accepted wisdom.

cheers Darrel

That thread was very interesting reading Darrel. These corys were Schultzeis, which aren't mentioned in the thread. The water in the bag was very milky looking and there did seem to some fish waste in there too. I did notice that one of the corys didn't seem too happy in the bag, swimming upside down a bit, but just put this down to stress from the journey.

In a way I'd like to think that this was the cause, does everything else seem about right to you?

Thanks,

Dan

If all the corys were in one bag for that time and the water as you say was milky then it could be that they were poisoned by there own waste?
When acclimatising them were you just adding water ? Or removing some and adding some? This is how I acclimatise and normally only take about half an hour tops unless it is a discus in which case I'll take a little longer but not much
Matt


Sent from my iPhone using Tapatalk

Hi Dan
I definitely think the demise of your fish was down to stress.
Also these water parameters are different from the fellow you got your fish from.
Here is what you quoted :arrow: I have a pH lower than my API test kit will read (6) and a very low KH. All other readings are fine including ammonia, nitrite, nitrate and GH.
I think this has been the deciding factor on the death of the fish.
A move from Ph7 to Ph6 could cause more stress.

I have watched fish react to a large water change and it does affect some fish.
This usually happened if the Ph was 6.5 and i added 60% of tap water that was Ph 7.6.
I had some very large tiger barbs they reacted by losing balance and buoyancy and going very dark in colour.... they recovered eventually.
After that i did 25% water changes.
So there could be a link between fish stress and large Ph/Kh/Gh swings when it comes to acclimatisation.
Cheers
hoggie

In my opinion I think people are too careful when introducing new fish. You can't acclimatise a fish to your tank water chemistry in an hour. Fish take a few weeks to fully acclimatise to a new tank. When I add new fish I just float the bag on the water for 5-10 minutes, add a couple of cups of tank water to the bag then net them out into the aquarium. I have done this with all of my fish and have never had a problem.

KH differences have an effect due to osmotic pressure issues but pH has very little direct effects. If 20 young fish are placed in a confined space the urine and feces concentration build up rapidly inside the bag and so does the CO2 they are exhaling. The CO2 lowers the pH in the bag and lowers the toxicity of ammonia, however, once you open the bag the CO2 escapes and the pH inside the bag increases rapidly. This has the effect of increasing the toxicity of the ammoinia in the bag. Ammonia is extremely toxic at higher pH. Spending an hour or more trying to acclimatize fish inside a bag is folly. The most likely cause of this event is that the damage was done to the fishes gills while they sat and waited for you to let them out. The gill damage causes them to slowly suffocate and that's why it took till overnight for them to perish. Young fish are especially susceptible to gill damage from ammonia.

I totally agree with Darrel. When you get new fish, the hazard is in the bag, not in the tank. Get those fish outta there as quickly as you can assuming temperature is close. As I understand it from your report, the Cories that were already in the tank did not perish and neither did any of the other inhabitants. Is that right? If so this lends credence to the theory of toxicity of the bag water. If only the new fish dies then this indicates that the damage which occurs was independent of the tank conditions because the original inhabitants are unharmed. If both new fish as well as original inhabitants die then this indicates something went wrong with the tank water.

Acid conditions in your tank water actually protects your fish from the toxicity of ammoina. You should be happy that the pH drops to low values, because this solve many more problems than it causes.

Cheers,

Wow, there are so many different opinions on this. The consensus seems to be, get the fish out of the bag as soon as possible. I think leaving them a few minutes for temperatures to start to equalise, and then get them out seems to be a good plan for future. You're right that the problem seems to be bag water rather than the tank water.

I shall try adding some more fish at some point when I feel brave enough, just a few this time to see how I get on.

With regard to the pH of the water, I have read about and been told about on here the fact that low KH readings can lead to pH swings as certain parameters change in the water over time. Therefore it seems sensible to try and raise the KH a little, and therefore the pH, to try and prevent this. I think I shall continue to use the API test kit for now, just more regularly to keep an eye on pH - particularly after adding the crushed oyster shell to monitor the effects.

Thanks for all of your thoughts on this one, hopefully I'll get it sussed soon!

I am a 'straight in the tank in the tank' type of guy!
I guesse a lot depends on how long the transit time from tank to tank will take.
There are three shops in my area & all of them are within a 15 minute drive, my method is to place the fish bag into a bucket lined with a T shirt that I then fold over the bag to keep warm & dark for the short drive home.
I then pour the bag contents into my unlit tank - just the same as my dad did!

Hi all,

my method is to place the fish bag into a bucket lined with a T shirt that I then fold over the bag to keep warm & dark for the short drive home. I then pour the bag contents into my unlit tank

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I've got a couple of polystyrene "fish boxes" for more fish or longer journeys, I take a change of water and a battery powered air pump. For shorter journeys I use a small insulated bag, I put an ice cream container in the bottom and the fish double bagged in the container inside the bag, I always take some extra bags with me. I've done this I had an impulse purchase at a local MA, and I got the fish in a single plastic bag, and they didn't have a darker carrier bag to put them in.

the fact that low KH readings can lead to pH swings as certain parameters change in the water over time.

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Yes this is true, the softer the water is the more the pH will fluctuate. The carbonate buffering will stop this happening by providing a reservoir of alkaline carbonate ions. Whether the fluctuations in pH in soft water matter is a moot point, and the answer is probably no, but some dKH/dGH won't hurt. Oyster shell grit is an easy option to add both dGH/dKH, or you could use the re-mineralising agent from "James' Planted Tank" <http://www.theplantedtank.co.uk/RO.htm> etc.James' Planted Tank is very well worth a read if you haven't already seen it

cheers Darrel