When to change the pH of a fish's water?

[twoluvcats]

I read your post about Ph above 7.6 being bad for bettas. My tanks are all at 8...with super hard water. But, what I've been told by other fish geeks is its way better to leave the Ph where it comes out of the tap than to try to chemically swing it around. So I was a bit shocked by your avocation to force it down. Now I feel like I should be forcing mine...at least in my betta tanks. Or is it a "of it ain't broke, don't fix it" situation?

[amanichen]

Here's three questions which I see frequently, and here's my answers to them:

If you get new fish, should you try to adapt them to your water chemistry?

It depends highly on where the fish came from. If your fish was raised in 6.5 and low hardness then I would NOT try to adapt new fish them to 8.0 and a high hardness. Forcing them to adapt to hard water with a high pH would significantly impact their longevity.

I'd make sure you get the pH for any new fish as close as possible to what they were living in from the breeder/store. The less you force them to adapt, the better off they'll be.

Should you try to change the pH for your existing fish?

I know it sounds like I'm arguing a technicality here, but if you go by that (flawed) logic that says any pH is fine, I should be able to keep a neon tetra in a pH of 8.5, with a hardness of 30dH and it should be fine. Unfortunately, that's just not the case. Even the captive bred ones will not thrive in an environment like that.

For most hobbyists, keeping a stable, but slightly improper pH is safer for the fish than the hobbyist trying to go about changing it, especially when they don't have a full understanding of water chemistry and how different chemicals affect the pH. The typical hobbyist will get into more trouble trying to change the water chemistry than they will keeping their betta in a pH that's slightly high or slightly low.

However, this isn't an unrestricted liscence to keep your fish in whatever pH you want to. Bettas in the wild often live in a habitat that changes seasonally. Most tropical fish from the ocean live in environments that measure changes over hundreds and thousands of years. And of course there's numerous fish in between these two extremes. If any fish could live in any water chemistry, then nobody would have any sort of trouble keeping exotic marine fish alive in captivity. If you know anything about saltwater fishkeeping then you know that a marine tank requires much more diligence than your average freshwater tank.

In short, it's best to leave it where it is, unless you're way off the mark. If your fish does best in pH = 6.5, and your water is 7.0, leave it. If your water is instead 8.5, you will want to look at gradually bringing the pH down.

What should I do when I decide to change the pH for my existing fish?

Changes don't have to be made suddenly and shouldn't be made suddenly. If you switch to the pH to 6.5 in a day, then, your fish will hate you. If you get to 6.5 over a month or two, the fish will have fewer issues. Water chemistry isn't horribly complex, but it's not as simple as pH-up and pH-down bottles either.

For more information on this read my article:

s94779296.onlinehome.us/website/Fish/articles/phchem.html

[twoluvcats]

Ok...so what do I do...cause they ARE all living in a pH of 8.0. I use a high range test kit, so I know its not higher than 8.

[amanichen]

twoluvcats said:

Ok...so what do I do...cause they ARE all living in a pH of 8.0. I use a high range test kit, so I know its not higher than 8.

If it was me I'd prepare water beforehand that was a mix of tap water, and distilled or R/O water. This would both lower the pH of the water, as well as soften it. So you mix water up that has the target pH you're looking for, maybe 7.4 to 7.6. You'll do water changes using that water, so eventually your tank reaches 7.6, or whatever you're shooting for. This change can be as slow as you want, but a month is a practical timeframe.

The pH drop in a normal community tank can be 7.0 to 6.6 in a month with no water changes, so there's lots of real world evidence that shows that many freshwater fish can easily survive a gradual change with minimal ill effects.

Again, whether you end up doing this depends on your choice. You might not notice any changes in the fish's health (positive or negative) from doing this pH change. For me, I know that if the pH is right, it's one less thing to worry about. It just what I'd do in the given situation =)

[twoluvcats]

Thanks Amanichen.

**sigh** Ok, looks like I'm going to have to push harder for our whole-house R/O system...*I* don't drink my tap water...so I guess I shouldn't expect my fish to live in it untreated. I'm going to leave the pH in my big tank alone. Everyone's ok in there...but my bettas do tend to have ragged tails (w/out fin rot)...and i have often wondered if it was our water doing it.

[starlight]

TwoLuv...I switched to 100% r/o water about two years ago. Many people use a 50/50 mix and that's great since the water has minerals in it. I can't do that since my buildings' water system was the problem.

I use a ten gallon tank to prepare the water with an AquaClear 150 filter to mix things. I use 1 tsp R/O Right to add back the minerals. <1/2 tsp salt, less than 1 teaspoon/10 gallons Seachem Neutral Regulor and the ph remains stable at 7.0. Getting the r/o was the best thing that I ever did for my bettas. Sometimes our water (mine) was not the best environment for our bettas. Ph is so important. I had problems with too low ph burning the fins.

[amanichen]

Here's another article that Twoluvcats found. It's supplementary reading which I agree with:

www.myfishtank.net/forum/showthread.php?t=26495