Could top-offs significantly affect pH?

[Azedenkae]

I realize that I top-off around 20% of my water volume a week (3+ gallons of fresh water added in a tank with 15 gallons of water).

Could this potentially reduce my pH significantly enough over time?

 

[Biglew11]

It all depends, are you dosing a little at a time throughout the week with an ato? Or dosing all at once? If dosed all at once then yes it could affect the ph but it should be temporary. Also if this is done all at once your other parameters would also swing wildly.

 

[DarthChaos]

Mine does, because I add Kalk to my ATO

 

[Azedenkae]

It all depends, are you dosing a little at a time throughout the week with an ato? Or dosing all at once? If dosed all at once then yes it could affect the ph but it should be temporary. Also if this is done all at once your other parameters would also swing wildly.

Either way my pH ended up lower than what the salt mix is (7.8 vs. 8.2), long term. It seems more like an issue with the large amounts of top-offs rather than whether it was done quickly or not.

 

[Azedenkae]

So, I am considering increasing the pH of my freshwater before doing a top-off, the only thing is I have never really ever wanted to actually do. But seems like it might be necessary. :/

 

[Garf]

Either way my pH ended up lower than what the salt mix is (7.8 vs. 8.2), long term. It seems more like an issue with the large amounts of top-offs rather than whether it was done quickly or not.

I would have thought this was organic / detritus building in your system rather than water changes unless the new salt has chronically low alkalinity.

Edit - are we talking freshwater top off or salt water-change

 

[Azedenkae]

I would have thought this was organic / detritus building in your system rather than water changes unless the new salt has chronically low alkalinity.

Not water changes, top-offs. Since the freshwater constantly introduced is closer to neutral pH.

 

[mdb_talon]

I really dont think the ph of your topoff is relevant to any large extent and should quickly equalize to the the same co2 level of the tank assuming you had adequate aeration.

Unless you are talking about increasing ph by using a alkalinity buffer of some sort, but then you are increasing your alk(which is fine if that is what you want).

 

[Garf]

Not water changes, top-offs. Since the freshwater constantly introduced is closer to neutral pH.

If it’s RODI it has little effect on pH unless it’s absorbed a lot of CO2 from the air, but even then it’s ability to lower the pH of saltwater would be minimal. How come you’re evaporating 3% / day? Guess you’ve got some nice weather.

 

[Azedenkae]

If it’s RODI it has little effect on pH unless it’s absorbed a lot of CO2 from the air, but even then it’s ability to lower the pH of saltwater would be minimal. How come you’re evaporating 3% / day? Guess you’ve got some nice weather.

Yep, or terrible climate depending on how you look at it. I live in Chicago, and it is a super dry place. We have to run humidifiers 24/7 or our skin starts cracking. Yep, that level of dry.

My actual water volume is 15 gallons, and I lose a gallon every two days. Very annoying.

I considered an ATO, but it looks kinda ugly. So I do manual top-offs. Creates a bit of a parameter swing, but nothing cares about it so have been keeping that up.

 

[BanjoBandito]

I have an overactive ATO due to my insistence on using a bigger pump than I should have in my overflow....I really have to watch it.

 

[jurgenph]

So, I am considering increasing the pH of my freshwater before doing a top-off, the only thing is I have never really ever wanted to actually do. But seems like it might be necessary. :/

don't dose anything just for the purpose of adjusting PH.
dose according to Alk consumption and the level you want to keep it stable at.

J.

 

[BanjoBandito]

don't dose anything just for the purpose of adjusting PH.
dose according to Alk consumption and the level you want to keep it stable at.

J.

This is the right move.

 

[KrisReef]

Yep, or terrible climate depending on how you look at it. I live in Chicago, and it is a super dry place. We have to run humidifiers 24/7 or our skin starts cracking. Yep, that level of dry.

My actual water volume is 15 gallons, and I lose a gallon every two days. Very annoying.

I considered an ATO, but it looks kinda ugly. So I do manual top-offs. Creates a bit of a parameter swing, but nothing cares about it so have been keeping that up.

I would think that would create salinity swings in the system. I also lose a lot of water to evaporation and the corals really enjoyed the stability of the ATO. I just have to remember to fill the 5 gallon bucket 1-5 times per week, depending on the weather, temperature, wind, etc.