Ph too low, why?

[ChickenScratch930]

Hi,

I have a twenty gallon tank with 4 rasboras, lots of snails, and quite a few plants including java fern, banana plant, moneywort, and several unidentified. My tap water is about 7.5 ph, and I try to keep my tank at 7 ph.

Recently my ph has been quite low, about 6.4, and I'm not sure why?

I have been doing small 10% water changes twice a week because my snails have been producing a lot of waste, and even after replacing some of the water my ph doesn't stay up.

What are the main reasons of ph being too low? waste? plants?

my ammonia and nitrite are at zero.

Thanks

 

[rdd1952]

My tap water is about 7.5 ph, and I try to keep my tank at 7 ph.

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Does this mean you are doing something to lower the pH from 7.5 to 7.0? If so, I'd say you are overdoing it. Do you have any driftwood in the tank or do you use CO2 injection for your plants? Both of those can lower pH. Have you checked the KH (buddering capacity) of your tap water? As for the pH of 6.4, that is actually just about perfect for the rasboras.

As a general rule, it's best not to try to "doctor" the pH (actually it's best not to use any chemicals other that dechlorinator). Most all fish can adjust to the pH of you water and do just fine. The one thing that is bad for them is a pH that bounces up and down and never stays consistent. Changes in pH are very hard on fish.

 

[ChickenScratch930]

I don't add chemicals to lower ph.I don't have any driftwood or co2 injection. I haven't checked the KH.

One of the main reasons I want the ph at 7 is because below 7 the snails shells can start to dissolve.

 

[rdd1952]

If your not adding anything to the water and it's still dropping, I'd say you KH is probably 0 or 1 like mine. If you can get your hands on some crushed coral (a very small amount) that will work to keep the pH steady. My tap pH is 7.0 and my KH is 0 so my pH tended to steaily drop. I experimented with some crushed coral I had and it works well. For a 20 gallon tank, try adding about 1/2 teaspoon to the filter pack (or simply hang or lay a filter pack in the tank with some in it if you are using something other than a HOB filter). Be careful not to use too much or your pH will jump too high. I use about 3/4 to 1 teaspoon in my 29 gallon and about 2 teaspoons in my 75 gallon and it works great.

 

[ChickenScratch930]

Thanks a lot for your replies . I had no idea about the KH .

 

[modernhamlet]

KH can definitely be a culprit.

Have you tested your nitrates? If they're high (not enough water changes relative to new waste) and your KH is low, that can cause pretty scary pH drops.

After testing, the first thing I'd do is a nice big 50% water change.

 

[Vivienne]

rdd,
Think I'll end up in the same situation eventually. Is crushed coral something you can buy ? Where do you get it from ?

 

[rdd1952]

You can get it from most any LFS. A lot of people that keep cichlids use it to keep the pH up in the 8.0 range. You really don't need much. It would be good if you could find someone in your area that you can get some from. As I said, for my 75 gallon, I only have about 2 teaspoons in the filter pack (just hanging in the tank) and I have never changed it or added to it in the 5 months I've had the tank set up. A handfull will be enough to last a very long time.