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

[TwoTankAmin]

We have pretty much omitted one important consideration in thiis thread, fish reproduction. In many cases this can be more parameter specific than survival requires.

Many soft water fish can not reproduce successfully in harder water. The reason is usually that the egg shell become to hard for the incipient wiggler to break through.

And why do we know how hard it is to spawn Altum angels or clown loaches in a tank. Part of it is hitting the right parameters and other conditions needed.

For almost any rule one can elucidate re keeping fish, I can find exceptions.
Rule #1 is that all fish live in water.
Rule #2 is that all fish need to eat some form of food.
Rule #3 is all species of fish must spawn or risk extinction.
Rule #4 is that it is easier, in a stable fashion, to raise most parameters than it is to lower them.
Rule #5 is you cannot keep a live 4 foot long fish in a 1 foot long tank.

 

[gwand]

On the Seriously Fish website the discussants frequently say that a certain species requires a pH between 4-6, for example, for breeding purposes. Sometimes the discussant will say the fish species needs soft water. Soft water and acidic pH are not synonymous terms. You can have very soft water and still not have a pH as low as 4. So I guess there is a place for pH in fish keeping.

 

[anewbie]

We have pretty much omitted one important consideration in thiis thread, fish reproduction. In many cases this can be more parameter specific than survival requires.

Many soft water fish can not reproduce successfully in harder water. The reason is usually that the egg shell become to hard for the incipient wiggler to break through.

And why do we know how hard it is to spawn Altum angels or clown loaches in a tank. Part of it is hitting the right parameters and other conditions needed.

For almost any rule one can elucidate re keeping fish, I can find exceptions.
Rule #1 is that all fish live in water.
Rule #2 is that all fish need to eat some form of food.
Rule #3 is all species of fish must spawn or risk extinction.
Rule #4 is that it is easier, in a stable fashion, to raise most parameters than it is to lower them.
Rule #5 is you cannot keep a live 4 foot long fish in a 1 foot long tank.

I fail to see with how this is related to using kh/gh instead of ph. If your kh is 5ppm and your gh is 6ppm your water is going to be very soft and acidic. If your kh is 300000ppm and your gh is 5ppm your water is going to be very alkaline. If your water is ....

The problem is that kh/gh are the relevant values NOT ph and if PH was the relevant value give me any sort of water you want and i'll pump enough co2 into it until it reads acidic but it still won't be suitable for a blackwater fish.

 

[WhistlingBadger]

On the Seriously Fish website the discussants frequently say that a certain species requires a pH between 4-6, for example, for breeding purposes. Sometimes the discussant will say the fish species needs soft water. Soft water and acidic pH are not synonymous terms. You can have very soft water and still not have a pH as low as 4. So I guess there is a place for pH in fish keeping.

True. My local water is very soft, but tends to have a fairly high pH. Most softwater fish seem to do fine, but they seldom breed. I suspect that, for the more finicky species, you have to get both right.

 

[anewbie]

On the Seriously Fish website the discussants frequently say that a certain species requires a pH between 4-6, for example, for breeding purposes. Sometimes the discussant will say the fish species needs soft water. Soft water and acidic pH are not synonymous terms. You can have very soft water and still not have a pH as low as 4. So I guess there is a place for pH in fish keeping.

No. The issue is that you can have low gh and not so low kh. The issue isn't ph but kh.

Anyway my very finicky softwater fishes breed just fine:


And I don't bother to measure their ph just their ec. These are said to require ph very low 5s to 4s to breed. Though just because someone claims that i have no clue what they actually require but they are much more finicky than some of my other species.

 

[gwand]

KH is determined by concentrations of bicarbonate and carbonate ions in water. KH is a measure of buffering capacity. The higher the KH the more stable the pH when tank conditions are threatened by factors that would unfavorably increase or decrease pH. KH is therefore a metric of pH homeostasis.

 

[anewbie]

KH is determined by concentrations of bicarbonate and carbonate ions in water. KH is a measure of buffering capacity. The higher the KH the more stable the pH when tank conditions are threatened by factors that would unfavorably increase or decrease pH. KH is therefore a metric of pH homeostasis.

I think in my crude and imperfect understanding it is more than stability; i think it is that buffering which holds the ion that raises kh. You can artificially change the ph (which is why i hate it when tools mention the ph) without fundamentally changing the water (injecting co2 is my favorite example); However over time the water will return to a stable value relative to its ability to hold ions. In my case i use water with near 0 kh and over time the ph tends to drift lower. For the above fish i do not measure the ph but on my discus tank i do have a ph meter (though i doubt it is accurate) which has drifted down to very low 5 or high 4 as the ec has settled around 27. Worse i'm not sure any of these cheap (less than instrument quality which might be $$$$$$$) ph meter are that accurate at very low end at least that is what others have told me. The home meters which cost around ~$100 are ok for basics.

I mostly just depend on ec and ack that if the water is soft enough the ph will be low. The real question i suppose one should ask is when starting from 0 just how much buffering does it take to raise the bar. Alas with our puny test kit that work off of drops we won't be able to guess that answer - and i just don't want to invest in a ppm kh test kit. The only good thing i can say is when i dip my finger in aquarium water that is 4.7 it doesn't burn like it does if i were to dip it in [pick your favorite OUCH acid]