"Acceptable" pH swing?

[enrgizerbunny]

I know this topic has the potential to turn into a firestorm, but excluding extra sensitive species (discus, GBR, etc) what would be considered an "excessive" swing in pH?

The reason I ask is because I am experimenting with baking soda to modify my tap water so that I don't have to age it. I got it pretty close this evening, and my tank dropped from 7.4-5 to 7.2. My rainbow shark isn't lethargic, which to me is a sign that it wasn't a very big swing for my fish, since he seems to be the most sensitive to it.

As far as the experiment goes (for those concerned). My tap water has a pH somewhere at or below 6 straight from the faucet. I need to get a lower range pH test to actually determine it. I added 1 tsp baking soda per 5 gallons. I think 2 tsp will do the trick next time. I do not have chlorine (well). This is my fix until I get a whole house neutralizing filter.

 

[Caliban07]

It might be a good idea to measure the dkh of your water then do some research to find out what dkh level is acceptable to prevent ph swings.

For example, reef aquarists typical aim for 8dkh as an absolute minimum.

If you know your current dkh and target dkh then you can use this calculator to maybe prevent ph swings.

http://reef.diesyst.com/cf/alkalinitycf.html

 

[mrvincent]

Fishs are really sensitive for PH swings. Raise KH and Ph will be more stable at higer values...

(Read on increasing KH with baking soda and/or calcium carbonate.

 

[Delapool]

On my ph up and down bottles I've seen 0.2 to 0.3 change over 24 hrs listed. I've never really used them.

I'd say 0.5 change is highest I've seen listed as ok but I'm not sure with co2 injected tanks (don't have one).

 

[mrvincent]

I'm using CO2 injection and I get 0.3 ph swings everyday/night. Fishs are fine since 6-8 months.

 

[enrgizerbunny]

Once the water is in the tank, I have crushed coral for stability, and my WCS is 50% every two weeks, or as needed. I have (what I believe) is dissolved CO2 in my tap, but I haven't bothered to test it yet.

Sent from my SCH-I435 using Aquarium Advice mobile app

 

[Caliban07]

You still have to be careful using baking soda though as too much will raise ph.

Carbonates bind with the hydrogen ion for stability. Since there are less hydrogen ions the solution becomes more basic.

It's trial and error really but obviously not good for fish. A change in .2-.3 can be 2-3 times more acidic or basic whereas a change in a ph of 1 will be 10 times more acidic or basic.

I don't think a small change in ph will be too drastic for the fish but a full shift of one may take it's toll if it is a fast change.

 

[enrgizerbunny]

The point of the baking soda is to raise pH. I draw 5 gallon buckets and then add baking soda.

Sent from my SCH-I435 using Aquarium Advice mobile app

 

[mrvincent]

Baking soda is to raise KH and sodium. Ph tend to raise with higher KH.

With higher KH, the PH is higher, but more stable.

KH must be raised slowly overtime, and aquarium require very little dose of baking soda, not huge doses or it'll stress fishs.

The best is to add baking soda to new water into the bucket for each water change, so it remains stable.

 

[mrvincent]

It might be a good idea to measure the dkh of your water then do some research to find out what dkh level is acceptable to prevent ph swings.

For example, reef aquarists typical aim for 8dkh as an absolute minimum.

Reef Alkalinity CalculatorÂ*©

My tap KH is 2 dKH° but I like to keep it at 4 in the tank. Here we're in a freshwater discussion.

But I keep my alk between 8 and 9 dKH° in my reef.

 

[enrgizerbunny]

The best is to add baking soda to new water into the bucket for each water change, so it remains stable.

This is what I am doing, and I have crushed coral in the filter to maintain the KH while it is in the tank.

I am doing this because my tap pH is too low and will change once it is aerated, which would wreak havoc on the fish if I didn't age/aerate it or treat it with baking soda, my only concern is if the pH will continue to rise as the water ages in the tank. I'll find out in a few minutes when I test.

Sent from my SCH-I435 using Aquarium Advice mobile app

 

[Delapool]

I've also found that my kh is varying over start and end of summer. Seem it get a higher kh in winter. I think I do more kh tests then anything now.

 

[enrgizerbunny]

Well it appears that the pH continues to raise as the water ages and becomes aerated in the tank, so now my pH is closer to 7.6. Fish don't seem stressed, the rainbow shark is active. I think I may have to invest in a RO unit if I ever want to fill a tank directly from the tap.

Sent from my SCH-I435 using Aquarium Advice mobile app

 

[mrvincent]

Well it appears that the pH continues to raise as the water ages and becomes aerated in the tank, so now my pH is closer to 7.6. Fish don't seem stressed, the rainbow shark is active. I think I may have to invest in a RO unit if I ever want to fill a tank directly from the tap.

Sent from my SCH-I435 using Aquarium Advice mobile app

Remineralize the RODI water before you put it in the tank

 

[enrgizerbunny]

Started new thread, disregard.

Sent from my SCH-I435 using Aquarium Advice mobile app