Low Ph

[confusion]

My ph situation is all jacked up, and I mean that sincerely.

I am trying to set up a co2 system, and I bought a ph controller. I calibrated it and it show the water in my tank at a ph of 5.8. The water coming out of my tap is around 8.2. Mind you, I do actually change the water about 50% per week in fact.

My concern is that 1) the ph in my tank is markedly different that my tap water and 2) if I start dosing CO2 to the level that I need, my ph will be roughly 5.1.

Will I have floating fish?

I have a myriad of gouramis (honey, dwarf, pearl, and gold), dojo loaches, a small herd of angels and about 5 swordtails.


So, I just finished draining off 50% of my tank and started refilling. Now the ph is back up to about 6.4 at the moment. Still has a lot to go.

Will my low ph cause problems for the fish?

 

[fry_lover]

how about ditching the co2?

none of them fish need a pH that low

 

[confusion]

That's not an option - I guess I'm stuck with having to use kh buffer.

 

[rdd1952]

Are you 100% sure the pH controller you got is accurate. Thats a huge drop in pH. Usually, high pH and high KH go hand in hand but not always. I would use a standard test kit to check the pH just to make sure. Also, test the KH of the water.

That being said, most fish can adjust to any stable pH. All of the fish with the exception of the swordtails prefer acidic water anyway so a 5.8 should be fine especially if you can rehome the swordtails.

 

[confusion]

I'm not at all convinced that the ph is stable. Nor my kh.

Earlier today - no CO2 dosing started:
ph: 5.8
kh: <10ppm

Immediately after 50% water change (about 4 hours ago):
ph: 7
kh: <10ppm

Now - with CO2 dosing, set point at ph of 6.5
ph: 6.5
kh: <10ppm

Tap water:
ph: 8.4
kh: 30ppm

I tested my water with a hagen master kit, and the ph was too low to measure when I first started (it only goes down to 6). The ph controller and the test kit agree on the current ph reading in the tank, and on the ph of my tap water.

 

[BigC]

Buy yourself a small Reverse Osmosis system. (cheap) With a DI cartridge attachment, this should lower you tapwater's pH and carbonate hardness levels, then mix the resulting water back with some tap water to get the desired level for you fish/plants.

 

[rdd1952]

It definitely sounds as if the CO2 is what is lowering it. What is the CO2 level of your water? It sounds as if you are just adding too much CO2 which in itself lowers the pH. I have a theory that deaths that are blamed on pH crash are often just due to a sudden rise in CO2 and the low pH is just a side effect. You said you couldn't stop with the CO2 but you may have to at least reduce the amount you are using.