# Low pH May Be Killing Some of My Fish



## BSquared18 (Mar 6, 2009)

Hi,

About a year ago I queried an aquarium expert at the Minnesota Science Museum about how to maintain neon tetras. He suggested using a combination of about three fourths reverse-osmosis and one fourth Minneapolis tap water, and replacing about four gallons of water once a week in my 30-gallon tank. As he suggested, I also put a live plant in the tank.

I have been following the water-change regimen consistently over the past year with generally very good results. In my 30-gallon tank I have, in addition to seven neons, a few black tetras, some skirted tetras, a couple congos, etc. They seem to be thriving.

Also in the tank was a large plecostomus that had been with us at least six or seven years. A while back I introduced a cory catfish to help keep the tank bottom clean. It died after a few weeks; I then introduced another one, which died within a day. Then, today, I noticed that the plecostomus was dead.

I checked the pH of the water, and the test sample was yellow, indicating an acidic condition of about 5.0.

I'm reasonably sure with the water changes I'm doing that the water hardness is low enough. The tetras seem to be doing fine. But should I do something to raise the pH somewhat so that fish like plecos and cories can co-exist with the tetras? Or should I not mess with it? From what I've read, adjusting the pH is tricky, since the changes can cause more problems than they solve.

Instead of keeping fish like plecos and cories in the tank, should I simply rely on vacuuming and scrubbing during the weekly water changes to control the algae and build-up of uneaten food?

I'm eager for suggestions.

Thanks,
Bill


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## BSquared18 (Mar 6, 2009)

By the way, the pH of the water going into the tank every week is about 7. One website suggested that, first, I probably don't need to change the pH since most fish can tolerate a wide range, and, second, if I want to raise it safely, add some coral (such as in a filter bag in the filtering system). Opinions?

Bill


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## Dmaaaaax (Nov 20, 2008)

Are you doing a strip test rather than a chemical test to get that reading or is 5.0 just the lowest the chemical test goes to? Neons are normally found in waters ranging from about 5.8 to 6.8 in the wild, but 5.0 seems a bit too acidic. 

Soft water is also subject to greater pH swings, and this is not good for the fish. You want to keep the water buffered a bit. I would shoot for a kH/GH of at least 2-3. This will keep your pH more stable when you are adding in 7.0 water.

Also do you have anything in your tank that could be lowering the pH like peat moss, or driftwoods?


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## BSquared18 (Mar 6, 2009)

dmaaaaax: "Are you doing a strip test?" No. A chemical test, so I don't know if the reading would go lower with a wider-range test. I'll look into buying some test strips.

dmaaaaax: "You want to keep the water buffered a bit." Would the tap water included in the water change do that? I've been working on the assumption that soft water is essential for neons. And all the tetras seem to be doing well. It's the bottom feeders that apparently suffered, for some reason. So, I thought I'd just vacuum the tank each week during the water change and not use any bottom feeders.

If I add a bit of crushed coral in a net bag in the filtration system, would that increase the water hardness along with increasing the pH? Again, I'm assuming that I should keep the water soft.

daaaaax: "...do you have anything in your tank that could be lowering the pH...?" Not really, except maybe what was used in the small container that contains a live plant I bought at a pet store.

Bill


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## Dmaaaaax (Nov 20, 2008)

Since you use a combo of RO/DI and tap, you can test your tap water for hardness and hopefully get to "better" mixture...ex.) 50/50? A kH and GH of 4 is still considered low but it would be better buffered than 1-2. This might also help stabilize your pH to around 6, which you could then read more accurately with your test kit. This would be preferred over having to add something like crushed coral.

Ohh, don't get test strips, they are useless compared to chemical testing. I wanted to make sure you weren't using strips to test your pH. Cory cats are also from the amazon area so they should be fine with an acidic pH. Consider shrimp as another alternative for bottom "scrubbers".


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## shocktrp (May 24, 2009)

You don't want the test strips - get the API liquid kit.

Do daily 50% water changes to get your PH back closer to neutral.


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## beaslbob (May 29, 2009)

I simply don't believe the pH of 5. 6.5 is much more believable. Perhaps a typo.

FWIW I have found that peat moss in the substrate allows neon tetras to thrive. I use 1" peat moss, 1" play sand, with 1" pc select (or aquarium gravel) layered from bottom to top. With that the dkh stays around 4 and dgh around 9 or so. For years with tap water and no water changes.

I also heavily plant the tank. after a couple of weeks my pH is 8.4-8.8 using the api high range test kit. The tank also has no circulation and no mechnical filters. Neons have lived for over 3 years in that setup.

.02


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