ph swing..

[giar]

sorry if i seem to ask too many questions.. but im here to learn.. so pardon me ...

i just did water change today. so after removing about 40% water, i double dose the seachem prime for my entire tank volume, then slowly add water direcrly from the tap.. i let it sit about 5minutes then i dose the seachem stability to compensate the compromised BB... then i turned on the filters etc... my tap water ph reading is about 6.2, my tank ph was about 7.5. after i did my wc the tank ph dropped to 6.5.. after one hour i checked the ph again, and now is at 6.8...my fish seems breathing heavily.. but they still have good appetite for foods and swim actively..

so is this ph swing ok for the fish? do i need to worry about the heavy breathing? is there anything i should have done differently?

ive spent hours to researched about ph swing, but most of the cases that i found in google was the ph of their tap water is higher than the tank, which is the opposite from my case.. since i couldnt find what i am looking for, so here i come to the forum again lol.. so im sorry to ask so many questions

 

[Yuki Rihwa]

*First, you will need to check whats the actual PH of your tap water after you lets it sit for few days in storage.
*Second, check your tank water PH after few days or before the water change to see the PH different compare to your tap water PH.
*Third, some fish species will withstand minor PH swing but some will not. If you experience the heavy breathing after water change then it's not a good sign, you will need to correct it for future WC or disaster will happen soon or later.

 

[giar]

*First, you will need to check whats the actual PH of your tap water after you lets it sit for few days in storage.
*Second, check your tank water PH after few days or before the water change to see the PH different compare to your tap water PH.
*Third, some fish species will withstand minor PH swing but some will not. If you experience the heavy breathing after water change then it's not a good sign, you will need to correct it for future WC or disaster will happen soon or later.

ok so does it mean i can not add tap water directly to my tank anymore? gotta let the water sit for 24-48hours prior to WC?..

 

[Yuki Rihwa]

ok so does it mean i can not add tap water directly to my tank anymore? gotta let the water sit for 24-48hours prior to WC?..

You can still add tap water direct to your tank but I would suggest do multi smaller WC (2 times a week or at least 1 a week) rather than a huge WC in a long time. Also, usually tank water PH tend to drop overtime not going up overtime unless you have something in your tank that make PH rise up overtime (crushed coral substrate for example), once you find the cause and correct it you will be fine and your fish will adapt to your water conditions.

 

[giar]

perhaps aeration causes the ph to go up?.. you mentioned about minor ph swing, is it like 0.5 swing? or less than that?

 

[Yuki Rihwa]

perhaps aeration causes the ph to go up?.. you mentioned about minor ph swing, is it like 0.5 swing? or less than that?

In my own tank experienced:
My tap water PH is 8.4+ and my tank water before water change is dropped to 7.6 after a week. I do 30%-40% WC every week and the PH different is less than 1 and my live stock are fine with it. I did went on a vacation before and I didn't do WC for a month and my tank PH dropped down around 6.4 and I did 75% WC and the PH swing did shocked my live stock and cause them have heavy breathing but they are fine few hours later.

 

[giar]

m

In my own tank experienced:
My tap water PH is 8.4+ and my tank water before water change is dropped to 7.6 after a week. I do 30%-40% WC every week and the PH different is less than 1 and my live stock are fine with it. I did went on a vacation before and I didn't do WC for a month and my tank PH dropped down around 6.4 and I did 75% WC and the PH swing did shocked my live stock and cause them have heavy breathing but they are fine few hours later.

mmm.. ok... tomorrow or 2 days later i will try to do 20% WC and adding water directly from tap water and see how my fish reacts.. i hope there wont be a huge ph change like today

so u said the water ph drops over time.. i took a sample of my tap water before i did my wc, i put it in a mug, now it has been about 12 hours and the ph reads 6.8 from originally 6.2.. im confused lol.. so there is something goin on with my tap water

 

[Pomatomus]

I believe I know your problem. 99% sure.

If your tap water comes in acidic and rises over time with aeration (gas exchange) then it is VERY likely that your tap water is high in CO2. This is fairly normal, especially with well water.

In water CO2 forms carbonic acid. This lowers the pH. It's a little different than dealing with other acids as if doesn't consume alkalinity, but will still lower pH. This means that after the CO2 gases off, the pH will come back up.

Your fish are breathing heavy because they are dealing with water high in CO2 and likely low in oxygen. Again, this is typical when you pump water from the ground. We pump 100,000 gallons of water from our well every day at work. It all has to run through a degassing tower or else it would kill our fish.

I would heavily aerate the water before or while adding it. This is easy with a small tank as you can let a bucket sit out for a couple of hours or just add an airstone to it for maybe 10 minutes. With a larger tank I'd add an airstone in the tank and keep it running as high as possible. I would also try to increase how much the new water mixes with air by spraying it into the tank or by dispensing it from higher up, creating lots of bubbles as it plunges into the tank.

You could also try to make some sort of an airlift that the water must flow through on its way to the tank.

Feel free to ask more about this if you're curious. Again, this sounds like a textbook case of dissolved gases. You should also aerate to prevent supersaturation of nitrogen. It's a silent killer for fish. Also common in water pumped from the ground.

 

[duanes]

I agree with the above, and doing smaller water changes more often, will help.
The pH may instantly drop because fish urine builds up, and the buffering capacity of the tap is being used up by the urine.
1 point on the pH scale is 100Xs difference in either acid or base depending upon which side of the scale. Many fish can handle that bump, rain is usually much lower in pH the say lake water.
The more dangerous part for your fish is the time between water changes where fish urine builds up in the tank between water changes. Doing a few smaller changes during the week will make for a more stable environment.

 

[Fish Tank Travis]

I think you can fix this by aging your water. My water behaves similar to yours. Out of the tap it is 7.6 and then rises to 8.4 if left sitting.

I got several 55 gallon plastic drums (have to be food grade) that I fill with the hose, let the water heat up with a 300W heater (will take the water from ~60 degrees to 80 degrees in less than ten hours) and keep a 200gph powerhead running in it. I then use this water for water changes once it's been sitting about a day or so.