Ph downs

[oldschool52]

I have had problems keeping Ph up. I add about 1 gal of RO/DI water each day to my 72g and about 1/2 gal of water to my 30g because of evaporation. I get the Ph somewhere between 8.1 and 8.4 then check it later (4-8 hrs) and it's down to 7.9 to 8.0
Finally figured it out !!!!

Everybody talks about TDS for RO/DI water. Mine is at 0. Never thought of checking the Ph. Checked Ph using a freshwater test kit and the Ph of my RO water is 6.2 . My tap water is 6.4. Only thing I worried about was TDS but now I add 1/2 tsp of sodium bicarb (baking soda) to each half-gallon of RO water that I use to top off tanks for evaporation. Ph of RO water is then 8.2. This has solved my Ph drop in my tanks and it now stays pretty constant.

 

[rostato]

Nothing you can do. Unless you wanna be hard core and add some baking soda to up the PH a little. Personally, I wouldnt care...

 

[tdwyatt]

CO2 wil go through your RO/DI filter, and as a result is what makese RO 2ater acidic. If you run a pump in your receiving reservoir that bubbles the water at the surface, or run a fountain with the water, it will reach whatever level your environment above the water will allow (based on the pCO2 of that air column). Using this water should not have an effect on your ultimate tank pH, as the buffer in the seawater will have the effect of driving the water to whatever pH is isoelectric for the buffer as the level of disolved CO2 reaches equilibrium with the air in the room.


HTH

 

[rostato]

I simply cannot get my PH over 8.0, ever. I tried for a while to get it higher, but ended up having to do water changes to fix what I messed up.

So I run an average of 7.8 all the time, and everythign in my tank is fine. All softies, LPS, SPS, and clams grow and look nice. Sometimes my PH will Peak on its own at artound 8.0 if the windows are opend but normally my tank runs at 7.8-7.9 durign the day, and 7.6-7.7 at night with my fuge light on.

Thats the percs of a new tightly sealed brick home...

 

[oldschool52]

I rechecked my data on ph of my RO water - yes it is 6.2 with the freshwater API test kit and my Pin Point Ph meter after I recalibrated it with calibration solutions. I then did some research to make sure I wasn't crazy and found this:

"Dr. Joseph R. Sachleben
>Research Scientist Campus Chemical Instrument Center
>The pH of RO water will start out near what the
>tap water was. The pH of DI water will start out
>neutral. After sitting out a while, both will
>go to a pH of about 5.5 because of CO2 disolving
>into the water."

"The pH of RO water will start out near what the
> tap water was. The pH of DI water will start out
> neutral. After sitting out a while, both will
> go to a pH of about 5.5 because of CO2 disolving
> into the water. The H2CO3, HCO3- buffer system
> ends up being the buffering that naturally occurs
> in RO/DI water.
>
> Joe Sachleben
> jsachleb at chemistry_ohio-state.edu"

Hope this helps.

I have had no more problems in over a week since I sarted adding 1/2 tsp of baking soda to each half gallon of ro/di top-off water. Ph in tank is now always between 8.2 and 8.3 with dkh @ 8.5 to 10. I've checked it on all 3 tanks and they are all stable.

 

[rostato]

My top off runs through a kalk reactor...still low PH

 

[rostato]

Yeah I am setting up my calcium reactor soon. Hoefuly that helps

 

[rostato]

that's what I lthink will help me. I am just trying to get my tank stable on a regular basis. Hopefully I can rid myself of Kalk.