I'm sick and tired of people talking about the 'PH' a fish needs

[anewbie]

One huge pet irritation is when people say "well my tap water is ph x so i should buy this kind of fish"; well it is bull horns ground down to mash.

What is important is the chemical composition of the water - usually broken down to kh and gh.

Now my comment is a bit of an over simplification but you give me water that is ph 8 and i can certainly turn it into water that is ph 6 in an hour or so and it will still be just as hard as it was prior and just as 'bad' for a softwater fish. PH is mashed horns and nothing more. If you don't believe me I'll let you put the super duper sensitive fish that requires (in your word) ph 5 to live in water with kh 10 and gh 20 with a ton of co2 so your favorite meter reads 5 and lets see how it does.

 

[Deleted member 155700]

I know the only other test my big box LFS does apart from the usual other 3 is PH, so combined with recalling fish deaths I had in the past, I assumed it was important, at least not to have wild swings. People also say fish will adjust to your PH, and to focus on stability. I don't know concerning water hardness - perhaps much of the lack of attention given to it has filtered through from the pet store trade not being informed enough and thus not advising customers comprehensively. The API liquid tests which virtually everyone uses: the full kit only supplies you with the PH, high range PH, ammonia, nitrite and nitrate tests (freshwater).

 

[TwoTankAmin]

For the most part one does not need to test for GH very often. It matter most when testing one;s water source. Once you know it's Hardness, you only need to check now and then to make sure ut has not changed. How ever, the cycle itself is acidic. This means if we do not do water changes, the pH of the water will drop over itme. This is typical in cases of old tank syndrome.

And then there is the consideration of the toxicity of the Total Ammonia (TA) in a tank. 2.5 ppm of TA in one tank at 77F and 6.8 pH is not seriously harmful and not nearly fatal. And then .60 ppm in another tank at 8.5 pH and a temp. of 82F can be doing harm and with long enough expoure may be fatal. Ph matters greatly here.

I will bet you most of you have never kept Alrum angels fresh from the wild. When I received them the second time they came into a tank that was pH 4.2 and the TDS were in the 30 ppm range. In the wild the TDS may have been a bit lower. As to why this matters has to do with the immune system of the fish.

Many bacteria cannot survive in a pH that low. This includes some of the ones which result in diseases common in our tanks. As a result the fish in the wild have their immune systems compromised as far as those bacteria are concerned. Since the bacteria are not in the wild the fish have not developed any immunity to them.

It is almost impossible to have a pH in the 4.0 range range and also to have anything close to hard water.

I tend to measure TDS as opposed to GH. I am usually more concerned with KH. What contributes to this is included in TDS but not in GH.

However, within reason, hardness matters more than pH, but not 100% of the time. And for the most part a low pH and low hardness usually go together as do higher hardness and higher pH. This is especially true when considering the extreme ends of the ranges.

What I find even more strange is sites which give a KH need for fish. Fish do not need any specific KH. However, since KH goes a long way towards determining the pH, and since KH contributes to TDS, it tends to vary based on the pH and TDS of any body or tank of water.

 

[Colin_T]

I think a better title would be pH and GH, not just pH on its own.

Fish do require a certain pH and if you get wild caught fish that come from water with an acidic pH, and put them into water with a high pH, there's a good chance they will all be dead within a month. This can happen regardless of if the GH is high or low. I have seen fish that were put in soft water (GH below 50ppm, KH around 50ppm) and the pH was 8.0 and they died within 2 weeks. They didn't have a disease and it wasn't water quality related, it was the high pH.

General hardness (GH) is another thing to consider and fish that come from soft water (GH below 150ppm) should not be kept in hard water because they can't get rid of the minerals they take up from the water. This leads to calcium deposits in their organs and premature death. It takes more than a few months to kill fish this way but it happens.

Keeping hardwater fishes in soft water is another issue and most fishes from hard water need lots of minerals in the water and in their body. Without these minerals they end up dying. Mollies are a classic example and get the shimmies when kept in soft water and they usually die within a month of being kept in soft water.

Carbonate hardness (KH) is of lesser importance but fish from soft water should not be kept in water with a high KH (above 150ppm). Generally a high KH is linked to a high pH and vice verse (low KH linked to low pH).

All three factors (pH, GH and KH) are important, with pH and GH being the most important, and KH being less of an issue unless it's really high and you keep soft water fishes.

 

[anewbie]

The bacteria aspect is important for different reasons however a fish that require soft water that has been transition to high ph (and the different types of bacteria found in alkaline water) should be fine as long as the water is soft. Now there is a partial contradiction here because sufficiently soft water should have low ph but of course we are talking more about theory than practicality so in this statement we have for the water to have an artificially high ph despite being soft.

However - as most of my tanks are now balckwater i am aware of the bacteria issue - the ammonia issue describe by @TwoTankAmin is real but also again not specific to fish requirement as it leans towards a more specialize incident. I stand by my statement that the fish generally speaking doesn't care about the ph as long as the mineral content is appropriate and the ph is stable.

 

[GaryE]

We love test kits, and pH was one of the first available. It's so easy to test.

For fishkeeping, GH and KH matter more. I go with TDS, because it's easier to measure and works for my purpose. I know my water from the tap, and can look up monthly reports from the city for variation. It's important to know your water. GH, KH, pH and TDS together give good info.

I was able to keep, but never breed altum angels for quite some time. But the average hobbyist doesn't take that leap into really difficult fish. pH at least gives a vague indication of hardness, although a real test of hardness is much more valuable.

 

[anewbie]

We love test kits, and pH was one of the first available. It's so easy to test.

For fishkeeping, GH and KH matter more. I go with TDS, because it's easier to measure and works for my purpose. I know my water from the tap, and can look up monthly reports from the city for variation. It's important to know your water. GH, KH, pH and TDS together give good info.

I was able to keep, but never breed altum angels for quite some time. But the average hobbyist doesn't take that leap into really difficult fish. pH at least gives a vague indication of hardness, although a real test of hardness is much more valuable.

I think the reason I got ticked off is people measure ph from the tap; but many water companies will artifically raise the ph to protect older pipes; much like the issue with bacteria acidic nature of water has other implications. However this artifically raised water might actually be soft and so inexperience people make broad incorrect assumptions based off of this ph reading. Of course they could resolved this issue by letting the water sit out in a container for 24 or 48 hours as most of these chemicals will dissipate (why i don't know just what i've been told) as does chlorine. More than once a person will declare their water is 'hard' water based off the ph only to discover that they actually have mild or even soft-water after letting it sit out overnight.

TDS is a useful base measurement though my vague understanding (please correct me if i am mistaken) is that many softwater fishes are more sensitive to long term calcium buildup (kh); of course this isn't totally true as certainly certain hard metals and similar would have a negative effect. For wild caught fishes they talk about blackwater, clear water and white water but all three tend to have very low kh.

Of course since my current interest is with dwarf cichild from the amazon most of my tanks are blackwater or near blackwater (after all i enjoy breeding these fishes and the eggs require soft water to become fertilize forcing me to push the tds down to low values even if the fishes can survive in water with higher mineral content.

My current view of ph is stability across the acidic/alkaline line is more important than the actual value. That is the nitrification bacteria is both sensitive and different but what is not clear to me is if it is the actual ph or the chemical composition that makes that ph (i.e, ion content). After all when you run a tank with co2 injection and you push the ph from 7.5 to 6.5 your nitrification bacteria doesn't die off and the tank doesn't crash @TwoTankAmin which makes me suspect it is more than the actual ph value that impact the bacteria.

 

[Magnum Man]

I have rock hard, alkaline water, here, from my well… rift lake Cichlids are popular in this area… I did them, when I had tanks 25 years ago, so I wanted something different when I restarted the tanks a couple years ago… honestly, I have not tested my water for anything, in the past 6 months ( since adding a dedicated RO unit for my tanks… I’ve gone completely away from adding any chemicals, fertilizer, or Ph, or remineralization… and I have fish thriving, I could have never dreamt of keeping prior to RO… I do add an Indian Almond leaf, every time the previous one disappears, and I do driftwood, in my scraping, and lots of hardy terrestrial plants grown out of the tanks… assuming most of my tanks are likely mid 6’s on Ph, but not something I monitor…

 

[anewbie]

I have rock hard, alkaline water, here, from my well… rift lake Cichlids are popular in this area… I did them, when I had tanks 25 years ago, so I wanted something different when I restarted the tanks a couple years ago… honestly, I have not tested my water for anything, in the past 6 months ( since adding a dedicated RO unit for my tanks… I’ve gone completely away from adding any chemicals, fertilizer, or Ph, or remineralization… and I have fish thriving, I could have never dreamt of keeping prior to RO… I do add an Indian Almond leaf, every time the previous one disappears, and I do driftwood, in my scraping, and lots of hardy terrestrial plants grown out of the tanks… assuming most of my tanks are likely mid 6’s on Ph, but not something I monitor…

Well this is way off topic; but yea ro water is great. My discus tank has become a forest of plants despite being ro water @83. Depending on the aquarium et all i use a combination of leaves/driftwood/peat to stablize the ph. My discus tank has no peat in the filter but the ph meter suggest the ph hovers around 5.7 - gotta say i don't know why so many people say plants don't grow in these conditions - i could never grow micro swords before but now the stuff is running amok and is quite aggressive weed (yea yea so some plants do better in soft water than medium soft water - what can i say). Forget the fishes just go with the plants

 

[Back in the fold]

You can’t change pH , in my experience , it always goes back to where it was . I have 8.0 and I use R/O water for the soft water fish I like and they are fine in alkaline soft water . I bought a test kit and rarely if ever use it . I wish I had the thirty bucks back . I take care of my water changes regularly and have never had any of the problems that the chemistry set says I should have .

 

[TwoTankAmin]

I have never stated that the nitrifying bacteria die off due to a low pH or a high pH. However, the pH of wtaeis the major determinant of how toxic any total ammonia in the water will be. Temperature also matters here but way less so than pH. However, the bacteria prefer ammonia (NH3) over ammonium (NH4). They can still use NH4, but do so much less efficiently than they can use NH3. The cycle doesn't stop in acid water, but it does slow, often markedly.

The nitrifiers are not so easy to kill, especially in a tank. When deprived of ammonia, oxygen or inorganic carbon they do not die, they go into a state of dormancy.

But, when it comes to any species of fish and pH/GH/TDS, there is not a single number any species needs for any of these things. What they do need is to be within a specific range. The further out of that range they get, the less well they will do. And that can shorten their lifespan or even kill them depending on the species and the conditions.

 

[Colin_T]

I think the reason I got ticked off is people measure ph from the tap; but many water companies will artifically raise the ph to protect older pipes; much like the issue with bacteria acidic nature of water has other implications. However this artifically raised water might actually be soft and so inexperience people make broad incorrect assumptions based off of this ph reading. Of course they could resolved this issue by letting the water sit out in a container for 24 or 48 hours as most of these chemicals will dissipate (why i don't know just what i've been told) as does chlorine. More than once a person will declare their water is 'hard' water based off the ph only to discover that they actually have mild or even soft-water after letting it sit out overnight.

That's what we have here. We get desalinated water (r/o) and they buff the KH so the pH is around 8.5. It's easy enough to drop but the pH is artificially high while the GH is 0ppm.

TDS is a useful base measurement though my vague understanding (please correct me if i am mistaken) is that many softwater fishes are more sensitive to long term calcium buildup (kh); of course this isn't totally true as certainly certain hard metals and similar would have a negative effect. For wild caught fishes they talk about blackwater, clear water and white water but all three tend to have very low kh.

TDS measures everything dissolved in the water and includes minerals, single celled algae, sediment, tannins, etc. In my opinion it's a rough way to measure the water and not as accurate as GH and KH test kits. However, they don't test for much either (GH measures calcium and magnesium chloride; KH measures carbonates and bicarbonates) so we're stuffed whichever way we go.

 

[GaryE]

we're stuffed whichever way we go.

Truer words have never been spoken.

We work with partially good tools, and do our best. For new aquarists, it seems like we overcomplicate things. To chemists, we're fumbling in the dark. Ideally, we should have water company results, KH, GH and pH tests, and test results from the aquifer or lake our water comes from. That is really complicating life .

I get my water from a blackwater lake system. It looks like Amazon water does in photos (I've taken a look at the lake). It's filtered to remove the tannins, and agents are added to harden it to protect the pipes. Before they did that, copper pipes were corroding all over town. It comes out of the tap at a high pH, and then drops to slightly acidic. I love this local water because it lets me easily keep all the weird African fish I love, as well as a lot of South American rainforest species.

I use a tds pen to monitor whether the hardness is rising. It is highly inexact, but it gives me an idea to work with. I also regularly take water samples from the tap I use, and check what's happening with the water supply. Its TDS varies (slightly) seasonally, as I'm sure the lake does with evaporation, heavy rain, etc.

 

[anewbie]

Anyway at least for the wc sa fishes i'm keeping; i think i'll just keep my target of 50 ec or lower and not worry about kh/gh
[The bulk of the tanks are below 25 ec; for those who don't know about ec 50 is 25 tds because there is no such thing as tds all your tds pens are really ec pens with the number 1/2; go figure - i.e, we arent' actually measuring total dissolve solids to begin with....]

 

[Naughts]

What does ec stand for? What is it measuring?