Low Ph but is tap water the reason?

[gordon30]

Hello,

Hoping someone can help please.

The tank is approx 5 weeks old.

Recently nitrite and nitrate levels have been good.

Notice yesterday they seemed high (0.25 - 0.5 mg/l) did 10% water change and then this morning still seemed high so did another 20% water change. This morning also noticed pH reading was 6.4 or less - limit of the test kit and KH was between 0 and 3, so low. Am I right in thinking low pH can affect good filter bacteria? Secondly low KH will lead to lower pH value.

I tested the tap water, wondered if there was a link - tap water results are again low pH 6.4 or less and as we live in Scottish Highlands a low 0-3 reading for KH.

So... should I do more frequent water changes to help with nitrites and keep an eye for a few days or do I need to raise the pH by adding bicarbonate of soda to tap water, if so what's the procedure / amounts to add etc

Thanks,
Gordon

 

[Byron]

The main issue right now is nitrite. Yes, daily water changes of 50-70% should be done until nitrite is zero and remains at zero. Using a conditioner that detoxifies nitrite would also help; Prime (by Seachem) is one, Ultimate (not sure the manufacturer) is another. These detoxify nitrite temporarily (24-36 hours) so the water changes are still needed but the changes plus conditioner will get the fish through this.

Do not attempt any pH adjustment. The pH is related to the GH and KH, and dissolved CO2 also factors in.

First thing to determine is the GH, KH and pH of your source (tap) water. You/we must know these values in order to go forward. And when testing pH in tap water you must ensure the dissolved CO2 (if any) is out-gassed; easiest way to do this is let a glass of tap water sit for 24 hours then test. This is only relevant to pH and tap water, not needed when testing pH in the aquarium water.

Second, what fish species do you now have, or intend having? Some will be fine with soft (if it is soft) and acidic water, some will not.

 

[gordon30]

The main issue right now is nitrite. Yes, daily water changes of 50-70% should be done until nitrite is zero and remains at zero. Using a conditioner that detoxifies nitrite would also help; Prime (by Seachem) is one, Ultimate (not sure the manufacturer) is another. These detoxify nitrite temporarily (24-36 hours) so the water changes are still needed but the changes plus conditioner will get the fish through this.

Do not attempt any pH adjustment. The pH is related to the GH and KH, and dissolved CO2 also factors in.

First thing to determine is the GH, KH and pH of your source (tap) water. You/we must know these values in order to go forward. And when testing pH in tap water you must ensure the dissolved CO2 (if any) is out-gassed; easiest way to do this is let a glass of tap water sit for 24 hours then test. This is only relevant to pH and tap water, not needed when testing pH in the aquarium water.

Second, what fish species do you now have, or intend having? Some will be fine with soft (if it is soft) and acidic water, some will not.

Hi Byron,

Thank you for the reply.

I will continue with the water changes and not try any pH adjustment.

I did test the tap water again, before your reply so did the test straight away and got a reading of 6.8 pH

Two types of fish - green neon tetras and cory dory. All fish look well and are lively in behaviour.

Even though I have been trying to feed only what's consumed in 3 mins once a day I could be guilty of overfeeding and therefore contributing from uneaten food decomposing. I have been removing left over uneaten food in the mornings. This is another area for me to get under control.

Thanks,
Gordon

 

[Byron]

I did test the tap water again, before your reply so did the test straight away and got a reading of 6.8 pH

This mighty be accurate or it might not due to the CO2. Test it after 24 hours. Or some suggest briskly agitating a small jar of tap water for several minutes, then testing; this can out-gas the CO2.

Two types of fish - green neon tetras and cory dory. All fish look well and are lively in behaviour.

These fish prefer soft and acidic water. If by "green neon" you mean the species Parachierodon simulans, this is a very soft and acidic water species. So a pH below 7, no matter how low it goes, is ideal. But we need to pin down the GH. If you do not already know this, see if you can get it from the water authority, check their website or call them. We need the number and their unit of measure (this can vary).

Even though I have been trying to feed only what's consumed in 3 mins once a day I could be guilty of overfeeding and therefore contributing from uneaten food decomposing. I have been removing left over uneaten food in the mornings. This is another area for me to get under control.

Yes, there should never be food left over in the morning. The upper fish should eat what you put in within a few seconds, not m inutes. Cories are a bit different as you feed them sinking foods and it can take an hour or two for the cories to dig through one of these tabs/pellets/disks, depending upon the type. Overfeeding causes health issues for the fish, regardless of nitrates and water issues.

 

[gordon30]

This mighty be accurate or it might not due to the CO2. Test it after 24 hours. Or some suggest briskly agitating a small jar of tap water for several minutes, then testing; this can out-gas the CO2.

I'll leave for 24 hrs and test again

These fish prefer soft and acidic water. If by "green neon" you mean the species Parachierodon simulans, this is a very soft and acidic water species. So a pH below 7, no matter how low it goes, is ideal. But we need to pin down the GH. If you do not already know this, see if you can get it from the water authority, check their website or call them. We need the number and their unit of measure (this can vary).

I've attached a couple of pieces of water quality info from Scottish Water, Killiekrankie is the supply to the house.

Yes, there should never be food left over in the morning. The upper fish should eat what you put in within a few seconds, not m inutes. Cories are a bit different as you feed them sinking foods and it can take an hour or two for the cories to dig through one of these tabs/pellets/disks, depending upon the type. Overfeeding causes health issues for the fish, regardless of nitrates and water issues.

Okay less food it is!

Thanks!

 

[gordon30]

off topic but I've had tropical tanks before, not for many many years and never seen one of these which I removed from the tank at the weekend.......think it arrived on the plants.

 

[Byron]

OK, in the first link the hardness (this is the GH) is given in mg/l [mg/l = ppm] and dGH. These two are the same obviously, and both units (ppm and dGH) are used in the hobby. There is variance for the different locations, and I've no idea where you are in this. Most are on the soft side (the one is moderately hard). The pH will have little buffering, so it will naturally lower in an aquarium. This is all fine for the soft water fish mentioned, and nothing needs to be done.

I have zero GH/KH souorce water, and I add nothing. The pH is in the 4-5 range in some tanks, low 6 in one or two others. I leave it alone for stability, and only acqujire suitable fish.

 

[Essjay]

Since the water quality report you give is for Killiecrankie, I presume we need to look at the hardness for there as well?

That area has hardness 57 ppm and 3.2 dH.



And your nitrate mean is 0.62 ppm. Many regions of the UK would give their eye teeth for nitrate as low as that

 

[seangee]

That area has hardness 57 ppm and 3.2 dH.
...
And your nitrate mean is 0.62 ppm. Many regions of the UK would give their eye teeth for nitrate as low as that

Actually just for water like that

 

[The Lumpfish Guy]

IF it helps The Ph in Scotland seems to be fluctuating at the moment, I think there is a lot of stuff coming from the hills into the water supply from all the storms/snow/rain or any permutation of all three.

@seangee and @essjay We are quite lucky in Scotland with the water quality. I was in Wilts before coming up here it it was almost concrete.And down in Plymouth the parameters fluctuated so much, SWW were rubbish at controlling the water supply

 

[Byron]

Now that we all agree that you have very soft or soft water, I can respond to your question on the pH lowering. [Lumpfish Guy has a valid point, the pH and also the GH/KH of the source water can be affected by external forces, but there is the natural chemistry in all aquaria that I am dealing with here.]

The GH, KH and pH are connected. The higher the GH/KH (these two usually go together but not always) the stronger their influence on the pH. They serve as a sort of buffer to prevent the pH fluctuating. This is one reason why using so-called "pH adjusters" is so dangerous--the natural buffering capability is going to override all attempts to change the pH up to the point where the attempts literally overpower the natural chemistry, and then you have pH crashes and dead fish. And it is also why successful adjustment of the pH (if this is even needed) must include adjustments to the GH and KH.

In any aquarium, the accumulation of organics causes an increase in CO2 as the many bacteria species break the organics down. This CO2, along with the CO2 being added by the respiration of fish, plants and other bacteria, creates carbonic acid, and the pH will naturally lower. How much/far this occurs depends upon the GH/KH and pH initially, along with the fish load (the source of most of the organics), water changes, live plants, etc.

There is also the diurnal pH shift. This is most evident in tanks with live plants. It is also natural, and occurs in all tropical watercourses. In the planted aquarium where it is most obvious, the plants take in CO2 during the daylight to drive photosynthesis, but at night they stop so the CO2 naturally increases. This means that the pH at the beginning of the day will be at its lowest, while at the end of the day it will be at its highest. This diurnal fluctuation is generally just a few decimal points, say from 6.2 at 8 am to 6.5 or 6.6 at 5 pm. This is why when testing pH you should always do the test at the same time of day if you want to get a perception of the basic pH. If you always test in the morning at say 9 am and the pH every day is around 6.2 or 6.3 you will know the system is stable; testing at say 6 pm and finding it is 6.6 might cause you to think something is wrong when it is not.

As you can see, a great many factors are involved--another reason never to target pH alone. It is all part of a complex biological system.

So in your situation, the GH/KH is quite low, so the pH will tend to lower naturally. Leave it alone. Provided you select fish that are suited to your water GH, you will not have problems. The fish mentioned earlier will thrive in your water. Enjoy them.