freshwater tank ...ph rebounding...

[swishy]

I have setup a 10gal tank a month ago with 2 neon tetras the cycling is almost complete with the ammonias , nitrites and nitrates at the right levels but the Ph is stuck on 7.6..I have been trying to get it down with 'PH Down' giving 4 treatments a day of 3 drops of the the 'PH Down' solution 3 hours apart but the ph is still at 7.6 today...
Please help..I do not have any crushed coral gravel or any plants in the tank..Also I am given to understand that the buffer simply maintains the ph once a balance is achieved so first i need to bring the ph down to desirable level and then use buffer to maintain it..
I am lost as to what to do..its so frustrating to check the ph everyday and it being stuck on the same number or just rebounding back to 7.6 even if it goes down to 7.4..
Help with some advice........

[An t-iasg]

Hi swishy and welcome to Aquarium Advice!

The pH Down is an acidic product. I'm afraid that adding that much acid to your tank, at frequent intervals of 3 times a day, will harm your fish. I use a mix of RO and tap water in my tanks to lower my pH, which is 8.0 to 8.2 from the tap.

I have to go now (I hear a horn beeping in my driveway!) I'll check back later, and I'm sure others will check in with excellent advice!

[chasgood]

What you are seeing is the buffer effect or KH. If you keep adding PH down you will depleat the buffer and then all at once the PH will crash. It is best to not use chemicals to lower PH. Better to let the fish get used to your water.

I am pasteing this from another site. http://www.netmax.tk/
German for Karbonate Hardness, also known as temporary hardness, buffer or alkalinity. Measured in ppm or degrees (divide ppm by 17.9), aquarists usually refer to how many degrees of buffer they have (dkH). Water with a low buffer is more susceptible to problems with pH instability. Any pressure on the pH, either from materials decaying (acidifying, causing the pH to drop), or from rocks leeching (adding calcium carbonates causing the pH to rise) will be more effective when the buffer is low. This can have undesirable effects in the normal routine of materials decaying (fish waste, dead plant matter, uneaten food etc). It is recommended to keep your buffer above 4dkH, and to be careful if your source water is normally below 4dkH. The effect of acidification it to consume the buffer, before affecting the pH, so as soon as the buffer is zero, pH swings will occur. While baking soda will boost kH without significantly affecting gH, the usual treatments for low buffer are to do more water changes, gravel vacuum more and add calcium carbonate leeching stones into the tank or filter.
Measured on a logarithmic scale, neutral water is defined as 7.0pH. Anything below 7.0 is defined as acidic, and above 7.0 as alkaline. A pH of 6.0 is ten times more acidic than 7.0 pH. Fish generally come from a pH range of 6.8 to 8.4pH, with several species coming from even greater extremes. Ideally, small fish should not be exposed to more than a 0.25pH change per day, while larger fish will tolerate 0.5pH per day. The ability of a fish to adapt to changes depends a lot on its size and condition.
It may be desirable to naturally soften your water and add some tannic acids (almost essential for breeding some species). Driftwood, peat moss, Terbang and Oak leaves are all commonly used for this purpose. Recipe depends on material being used.

There are chemical means to acidify water (highly acidic solutions). Chemical methods have a tendency to either produce no pH changes (while exhausting the buffer) or cause a very significant pH drop (after buffer has been exhausted). For this reason, chemical methods should only be used in storage containers (or aquariums without fish) while slower natural methods can be used in the aquarium with fish (with some monitoring).

[TankGirl]

There is no reason that you can't keep happy fish in an aquarium with 7.6 pH. Mine is 7.4 out of the tap and I have no trouble at all with many different fish. So many fish are bred in harder, more alkaline water, like what is found in Florida where many LFS fish start their life, so if you want to reduce your stress and make your maintenance easier you can skip it.

Otherwise, a simpler way is the one suggested by An t-iasg, mixing RO water with every water change.

[AtodaJ]

Agreed

Stop trying to change your PH. A stable PH is MUCH more important than the actualy number. Products like PH Down should be banned in my humble opinion. Many a fish have they killed.

[An t-iasg]

Hi swishy,
How are the fish today? What is your pH out of the tap? Get a glass of water out of the tap, and let it sit out for 24 hours, then measure the pH.

If it is 7.6, I agree with the others that it should be fine. Fish are adaptable and a stable pH of 7.6 will be fine for them.

If you still want to lower the pH, use a mix of RO and tap water. I get some RO water from a machine at the grocery store. It's 39 cents a gallon. I mixed different amounts of RO and tap water and measured the pH, and I ended up at a mix of half tap water and half RO water for a pH of 7.4-7.6. I have two 5.5 gallon tanks, so I use one gallon of RO water a week. Your tank is also small enough that getting some RO water at the store shouldn't be inconvenient, but as TankGirl said, your tank maintenance will be easier if you don't need to.