Hypoxic fish but only after the waterchange?

[lazybones51]

I don't use a water conditioner because we have a specific chloramine cartridge for that, and a carbon filter too. I would go through a bottle a week with a tank this size! The dimensions are 216 cm long x 45cm deep x 54cm high. I do have sand in the fluidized bed, its been a favourite for Discus fish keepers. I cannot remember what the flow rate is, it was originally calculated to produce 10 x the volume an hour (at least) but it probably doesn't do anywhere near that. The spray bar at the back has pretty poor flow ( we drilled the holes too big due to a miscommunication btn husband and I!) so we added the external sponge filter ( which is about 20litres ). I was informed on UKAPS that conventional test kits were so inaccurate they wasn't any point using them so I focus more on water changes and syphoning out crap every week instead.

Prime is incredibly concentrated, with 5ml treating 200l of water. For the price it's worth doing even if you are using another form of filtration.

 

[Cat]

Hi all,

I experienced something similar a few weeks ago.

I hope I am understanding from what I read:
You water change at 7:30 PM, CO2 off at 5:30 PM and lights still on from 1-9PM - water change completed at 8:30 PM no ramp. Fish show signs of distress at 8:30 PM.

My thought is a sudden”Ish” change in dissolved oxygen levels.

This can very easily be ruled out if right after that water change your plants are pearling intensely.

If you use a holding tank for your water prior to putting in the tank, the the oxygen levels will be lower. I am also not sure how your filtration will Impact O2 levels.

You are water changing at 6.5 hours after lights on - the water at this time is super saturated with oxygen from the plants. If you pull out that water and add lower DIssolved oxygen water, the sudden change may be hard on the livestock.

Just some thoughts!

Josh

No I'm doing the water change at 7.30 am fi

Do you have a protocol for ensuring they are not exhausted?

Yes we have dates in the

That because you haven’t read my extensive posts on the topic

The biggest inaccuracy with hobby grade test kits is......
The Hobbyist

(this has been shown many times by aquarium clubs (mostly reef clubs seem to do the experiments), fish magazines etc)

API isn’t my first choice in test kits, but for an economy price they produce a decent kit that will show trends and approximate values for most parameters that are of interest/use to aquarium keepers

Angel fish are NOT one of the ornamental fish species that are particularly sensitive to “osmotic shock” or moderate pH shifts or moderate CO2 levels
(though you’re perhaps talking about wild caught angels? if so which species?)

That they are showing distress after a water change that should be reducing CO2 (there is extremely low likelihood that your tap water has dissolved CO2 levels anywhere near 30ppm) indicates something changes with this new water
It’s interesting that only the juvenile angels are reacting so visibly


5ml of Prime treats 200litre of water (for actual ammonia and chloramine levels neutralized, check Seachem FAQ etc - the numbers no longer appear on the bottle label) - if you’re only doing 1 x 50% water change per week, a 500ml bottle should last several months

I suggest testing the effect of Prime as this is a very quick check (testing the water quality after the 3 stage filter will likely cost more)

As you mention a spray bar, this should provide loads of “splash” during the water change, so CO2 levels should be significantly lower than when the tank is full and running - or are you turning the filter OFF during water changes?


Perfect

Always used them 20 years ago when I wasn't keeping plants, they seemed reasonable enough to show general trends, mind you whatever they said you ended up doing the same thing ie a water change. We used them when we did the fishless cycling with ammonia etc.....
calender to change them but we are changing now again anyway because they were doing work in our road a few days ago which resulted in running brown bath water

 

[Cat]

Do you have a protocol for ensuring they are not exhausted?

We have dates written in the calender, although we were about to change them early anyway as there was some work going on in the road and it made the water run brown for half a day so we thought that may have saturated the carbon filter. That was a few days ago though and this hypoxia after a water change has happened before with the Discus so I thought it was worth asking the question anyway.

 

[Cat]

I'll order some I think, just in case, it'll be better than hurting the fish...

 

[dw1305]

Hi all,

although we were about to change them early anyway as there was some work going on in the road and it made the water run brown for half a day

"Prime" is a good idea. <"Your tap water"> will almost certainly have been treated with an <"emergency" chloramine dosing">.

cheers Darrel

 

[Cat]

Hi all, "Prime" is a good idea. <"Your tap water"> will almost certainly have been treated with an <"emergency" chloramine dosing">.

cheers Darrel

Cambridge water seems to do this quite a lot!

 

[Cat]

You water change at 7:30 PM, CO2 off at 5:30 PM and lights still on from 1-9PM - water change completed at 8:30 PM no ramp. Fish show signs of distress at 8:30 PM.

I change the water at 7.30 am whole water change is finished before 10.30 when the Co2 comes on for 8 hours and the lights go on at 1.00pm for 8 hours. This was so we'd actually get a chance to see the tank with it's light on as we are usually out most of the day.

 

[dw1305]

Hi all,

Cambridge water seems to do this quite a lot!

The limits on faecal coliform in drinking water are <"really strict"> (and they need to be), but one knock effect of this is that any potential breach in the integrity of the water main is likely to be met by emergency chloramine dosing.

Anywhere in the <"SE of England"> is likely to experience the triple whammy of <"shortage of supply, agricultural pollution"> and a <"lot of new builds">.

cheers Darrel

 

[Cat]

Hi all, The limits on faecal coliform in drinking water are <"really strict"> (and they need to be), but one knock effect of this is that any potential breach in the integrity of the water main is likely to be met by emergency chloramine dosing.

Anywhere in the <"SE of England"> is likely to experience the triple whammy of <"shortage of supply, agricultural pollution"> and a <"lot of new builds">.

cheers Darrel

Describes Cambridge perfectly! We have really high nitrates as well, at the limit last time I checked apparently from fertilizer run off. I don't suppose you would have any idea why we only seem able to get a breakdown of the water readings/test results from 2 years ago and none more recently? I emailed them once about phosphate and they emailed me back 9 months later with a phosphate measurement!

 

[jaypeecee]

Hi @dw1305

My guess is that it is CO2 in the tap water.

Do you happen to know how much CO2 is in tap water? And, is it the result of atmospheric CO2 or is it added by water companies?

JPC

 

[dw1305]

Hi all,

I don't suppose you would have any idea why we only seem able to get a breakdown of the water readings/test results from 2 years ago and none more recently? I emailed them once about phosphate and they emailed me back 9 months later with a phosphate measurement!

No, not really, usually you should be able to get water results for the previous year.

The issue with phosphates is that there isn't a legal limit, so they don't have to measure PO4---, basically they can't be in breach of the EU limits, because there isn't one. Elevated levels of phosphate in water are associated with algal blooms etc, so you may get a <"phosphate stripper"> at a sewage works, but there aren't any particular health issues for humans.

Water companies actually add PO4--- to drinking water so that it <"can precipitate out any lead (Pb)"> etc.

is it the result of atmospheric CO2 or is it added by water companies?

I think normally it is just because the water in the main is cool and under pressure, meaning that it can hold more dissolved gases.

Water companies try and avoid too much CO2 in the water main, because it depresses pH and makes metal solubilisation more likely.

cheers Darrel

 

[jaypeecee]

I think normally it is just because the water in the main is cool and under pressure, meaning that it can hold more dissolved gases.

Thanks, Darrel.

That would make sense.

JPC

 

[sparkyweasel]

Cambridge water seems to do this quite a lot!

That could exhaust your filter sooner than expected. It wouldn't hurt to change it early.

 

[alto]

I'll order some I think, just in case, it'll be better than hurting the fish...

Prime keeps for ages, and it can be useful to have on hand
(It’s worth reading though the Seachem FAQ and Discussion Board posts - if it manages to come back online)

Your water prefilter system should be working (though there are enough anecdotal reports of problems that it’s always something I suggest checking)

Typically ground water will have dissolved CO2 levels of less than 10ppm, though deep ground water measurement may be much higher (eg, 100ppm though I don’t know how typical these much higher values may be), but it also doesn’t take much swirling or agitation to reduce this dissolved CO2 level

If this effect is something you’ve noted over the years, I’d be inclined to pick up a Hach CO2 test kit
If you’re interested in doing this, I’d suggest some reading first so you understand the limitations of this methodology
The Krib (always a good resource - though this summary is a bit digressive)
https://www.thekrib.com/Plants/CO2/test-kits.html#1

Aquaculture facility notes on using this Hach test kit
http://agrilife.org/fisheries2/file...-Instructions-for-Hach-Water-Quality-Kits.pdf

Open access article - there may be more suitable studies but this one offered an accuracy comparison with the CO2 titration method - only Test Series 1 is notable as it examines CO2 measurement in freshwater

Comparative performance of CO2measuring methods: Marine aquaculture recirculation system application
https://www.sciencedirect.com/science/article/pii/S0144860910000683

Test Series I results are summarized in Table 1. Barometric pressure (BP) was stable at 749 mm Hg, the total dissolved solids concentration was approximately 0.6 g/L, water temperature and dissolved oxygen ranged between 15.2–15.6 °C, and 10.1–10.7 mg/L, respectively. The differences between readings from the two HSU readings were small, ranging between 0.1 and 0.2 mg/L. Precision of the HSU readings, as measured by the coefficient of variation (CV = [100 × SD]/mean), ranged from 0.93 to 3.72 and averaged 1.85% for the two units. The precision of the HSU output was better than that determined for the CO2 probe (4.09%), and the titrimetric method (5.84%). HSU based DC results were lower than those measured by the CO2 membrane probe or the titration method.

As shown in Table 1, at the low CO2concentration there was no difference between the head space units and the CO2 probe.
The CO2 concentration determined using HSU 1 and 2 were 21.5 ± 0.8 and 21.6 ± 0.2 mg/L and the CO2 probe was 22.7 ± 0.8 mg/L (mean ± SD)
Titration did yield a much higher result, 28.1 ± 4.3 mg/L which was only significantly different from HSU 1.

At the medium and high concentrations the CO2 probe results were significantly different than the result from the HSU 1 and 2 and titrimetric results.
At the medium CO2 concentration, HSU 1 and 2 yielded 38.3 ± 0.4 and 38.2 ± 0.5 mg/L, respectively. The CO2probe yielded 42.3 ± 0.9 and titration results were 40.1 ± 0.6, both significantly different than the HSU results (P < 0.05) and each other.

At the high CO2concentration trial, HSU 1 and 2 and the titration results for CO2 (51.5 ± 1.1, 50.7 ± 1.0, and 55.2 ± 0.4 mg/L) were significantly different (P < 0.05) from the CO2 probe measurements (61.9 ± 4.1 mg/L).

 

[dw1305]

Hi all,

but it also doesn’t take much swirling or agitation to reduce this dissolved CO2 level ...............If this effect is something you’ve noted over the years, I’d be inclined to pick up a Hach CO2 test kit

It won't give you a quantitative value, but there is actually a really quick visual test you can use if you have hard (carbonate rich) tap water, like @Cat.

Just run the cold tap for a little while (couple of minutes) and then draw a glass of water. Ideally you want plain glass, something like a pint sleeve glass. You also need reasonable light and a dark back-ground.

If there is appreciable levels of dissolved CO2 you will see calcium carbonate form and precipitate out as the CaCO3 scale. Often all you get is a slight "milkiness" and the limestone scale isn't obvious as a precipitate in the glass.

cheers Darrel

 

[Cat]

Respiration is mainly driven by the bloods [CO2] esp in mammals, fish do have O2 receptors in their gills however its the high [CO2] in the blood thats dangerous to us and fish as it results in a lower pH of the blood, this change in pH changes the equilibrium of many chemical and biochemical pathways which if not corrected can be fatal.

Does the pH of the tank water directly effect the blood pH?

 

[Cat]

Hi all, It won't give you a quantitative value, but there is actually a really quick visual test you can use if you have hard (carbonate rich) tap water, like @Cat.

Just run the cold tap for a little while (couple of minutes) and then draw a glass of water. Ideally you want plain glass, something like a pint sleeve glass. You also need reasonable light and a dark back-ground.

If there is appreciable levels of dissolved CO2 you will see calcium carbonate form and precipitate out as the CaCO3 scale. Often all you get is a slight "milkiness" and the limestone scale isn't obvious as a precipitate in the glass.

cheers Darrel

I have a Hanna pen that does TDS, uS and pH, so I know I have high solids and can do pH easily before and after water changes and test straight from the tap. I presume a CO2 test would only be valid for a relatively short while as it gasses off? My husband is an electronic engineer and is interested in making a pH test that would measure the pH constantly ( out of interest more than anything else ) but its probably going to be a long time before he has any time to do it in reality so we'll probably have to stick with pen for the foreseeable future...

 

[dw1305]

Hi all,

I have a Hanna pen that does TDS, uS and pH, so I know I have high solids and can do pH easily before and after water changes and test straight from the tap. I presume a CO2 test would only be valid for a relatively short while as it gasses off?

Yes, you would need to stop the CO2 gassing off, which means minimising the gas exchange surface area. Sealed in a screw top bottle would be fine, it works for carbonated drinks and <"they have an immense amount of dissolved CO2">.

Conductivity will go up, but that is mainly a temperature, rather than ionic, effect. You can get an <"ion selective electrode"> for CO2, but I've never seen one.

You could look at pH, and you would theoretically get a rise in pH (as the CO2 out-gasses) that could be used to calculate the dissolved CO2 content. This is how <"drop checker works">.

The problem is that your tap water contains a lot of dKH (somewhere around 20 dKH), which means that you need a large amount of CO2 dissolved before you get much drop in pH away from the carbonate equilibrium ~pH8 value.

cheers Darrel

 

[Cat]

Hi I just thought I'd let you know I'm doing a water change today. I've added Prime ( I had no idea how concentrated it was amazing stuff!) although it does say that if I'm adding it directly to the aquarium I should dose for the whole tank volume so I have to dose twice as much? I have replaced the carbon and chloramine cartridges too. I'm doing a pH profile today, just out of interest, and I'm doing a profile tomorrow so I've got one without a water change in it.

Thank you for all your advice.

 

[lilirose]

Hi I just thought I'd let you know I'm doing a water change today. I've added Prime ( I had no idea how concentrated it was amazing stuff!) although it does say that if I'm adding it directly to the aquarium I should dose for the whole tank volume so I have to dose twice as much? I have replaced the carbon and chloramine cartridges too. I'm doing a pH profile today, just out of interest, and I'm doing a profile tomorrow so I've got one without a water change in it.

If you're adding it directly to the tank, yes, you have to dose for the whole tank.