PH Question regards tap water.

Aldofish
Member
I've been reading through this thread and as helpful as it has been, I feel that I still need to ask as my situation seems a little more drastic than a lot of the situations I am reading about.

After having had a problem with dropping Ph (from 7.6 to below 6 in a matter of hours.) I have discovered that My Ph reads at 7.6 from the tap, however, If I take a second sample and shake it for a while to "gas it off" the same water reads at below 6. How far below 6 I cannot tell. I already have crushed seashells in the filter and also a bunch of them in the bottom of the tank. These were put there to combat the Ph lowering properties of the driftwood i have in the aquarium. These do not seem to be making any difference.

The tank itself is a 40 long which is coming to the end of its fishless cycle. I have been buffering? the Ph with Bicarbonate of Soda to keep it around the 7.5 level and this has been working fine and the cycle has held.

How can I manage this? The water in this area is also notoriously soft. One of my big concerns is doing water changes once there are livestock in the tank as there will be notable swings in the Ph if I am adding my source water. I've looked into getting a Water Butt, but am concerned this might be a difficult thing to maintain. I would hope to stay away from chemical solutions as that seems to be a "Band Aid" rather than a proper fix.

Any thoughts?

Thanks in advance fish heads
 
Mudminnow
Member
That is odd. I've always had water that rose in pH after leaving it out a while. This is often due to there being more dissolved CO2 in my tap than water that just sits around. So, once it off gasses, the pH rises. Given that your pH falls, I would guess that, for some reason, your water source has next to no dissolved CO2. After you set it out, it is not "off gassing", but "in gassing." I mean the water might be absorbing atmospheric CO2 to drop your pH. Now I'm not a chemist, and I don't know if the typical 2-3ppm of CO2 in standing water is enough to entirely account for your pH drop. But, that's my guess.

On the up side, I've found pH swings are not a problem. I've kept several high tech planted tanks where the pH swings between night and day, and it never stresses any of the fish or plants. It is not the swing but the pH reached. I mean, if you have fish that need hard water, they won't like the pH swinging low. But, if you have fish/plants from soft water environments, they won't be bothered by it at all.

If you're worried about soft water impeding your cycle, I wouldn't be. There are many soft water habitats around the world that process nitrogen just fine. I myself had a 75 gallon black water tank for years. In this tank, my substrate was pure peat, there was a ton of driftwood, and I was injecting CO2. My source water was very soft: close to 0 KH and 0 GH. My pH fluttered around 5.0 or so. I had no trouble cycling this tank. And, despite it being fully stocked with fishes, I never ran into any problems.

So, if I was in your situation, I wouldn't bother tinkering with buffers and such to try and keep my pH in a specific range. Instead, I would just keep livestock that was from soft water environments.
 
  • Thread Starter
Aldofish
Member
Mudminnow said:
That is odd. I've always had water that rose in pH after leaving it out a while. This is often due to there being more dissolved CO2 in my tap than water that just sits around. So, once it off gasses, the pH rises. Given that your pH falls, I would guess that, for some reason, your water source has next to no dissolved CO2. After you set it out, it is not "off gassing", but "in gassing." I mean the water might be absorbing atmospheric CO2 to drop your pH. Now I'm not a chemist, and I don't know if the typical 2-3ppm of CO2 in standing water is enough to entirely account for your pH drop. But, that's my guess.

On the up side, I've found pH swings are not a problem. I've kept several high tech planted tanks where the pH swings between night and day, and it never stresses any of the fish or plants. It is not the swing but the pH reached. I mean, if you have fish that need hard water, they won't like the pH swinging low. But, if you have fish/plants from soft water environments, they won't be bothered by it at all.

If you're worried about soft water impeding your cycle, I wouldn't be. There are many soft water habitats around the world that process nitrogen just fine. I myself had a 75 gallon black water tank for years. In this tank, my substrate was pure peat, there was a ton of driftwood, and I was injecting CO2. My source water was very soft: close to 0 KH and 0 GH. My pH fluttered around 5.0 or so. I had no trouble cycling this tank. And, despite it being fully stocked with fishes, I never ran into any problems.

So, if I was in your situation, I wouldn't bother tinkering with buffers and such to try and keep my pH in a specific range. Instead, I would just keep livestock that was from soft water environments.

That sounds good enough for me. Thankyou
 
Dechi
Member
Soft water refers to GH, not KH. If you want to know how soft your water is, you need to measure GH.

If your fish are good to live in a PH of 6.0, then don’t do anything to it, except letting the water sit for 24 hours before using it to make a water change. If not, your fish will have to endure the PH swing, which is not ideal.

If you want to help your PH go a little higher and fluctuate less, you could use aragonite sand as your substrate. A good 2-3 inches should help raise the PH 4-5 degrees. It will take a while though, it doesn’t happen overnight.
 

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