RO Water exclusively

[Squawkbert]

Something is wrong here.

If you are replacing your WC water with RO/DI water after five 30% WCs only17% of the original water should remain in your tank.

TR

But, if that 17% has appreciable buffering capacity, pH won't move until it's nearly all gone. Remember, the titration curve for a buffered system, or system w/ a strong acid or base is sigmoid shaped, so you see nothing linear about the pH and % salt/acid/base remaining in the water.

 

[jones57742]

Squawk:

Please note that I was very careful in the wording of my post as I could not explain as concisely as you have inverse logarithmic Ph.

TR

 

[sschind]

Another thing that I have always thought is that the fish waste and decomposition from the plants has to replenish some of the minerals in the system. For top off I would think RO/DI would be fine as, like sqwuak said, the salts do not evaporate.

 

[haiau79]

But, if that 17% has appreciable buffering capacity, pH won't move until it's nearly all gone. Remember, the titration curve for a buffered system, or system w/ a strong acid or base is sigmoid shaped, so you see nothing linear about the pH and % salt/acid/base remaining in the water.

hmmm, so when will the ph start to drop? I'm gonna do another WC tomorrow using pure RO water again.

 

[gmh]

What is the source of this RO water? Have you measured it for GH and KH? Sometimes water marketed as RO can be quite hard if it has not been serviced properly.

 

[haiau79]

What is the source of this RO water? Have you measured it for GH and KH? Sometimes water marketed as RO can be quite hard if it has not been serviced properly.

I get it from a water store across the street. Its the best water in town!

 

[jones57742]

hmmm, so when will the ph start to drop? I'm gonna do another WC tomorrow using pure RO water again.

This is rough but when you have completed seven 30% WCs with the RO/DI water your Ph should be approximately 7.4

TR

 

[SchizotypalVamp]

Hope you don't have any fish in the tank, it could drop quickly and drastically

 

[Rbishop]

I get it from a water store across the street. Its the best water in town!

Got a shot of the bottle label?

 

[OldMan47]

RO water is very low in minerals so it can be dangerous to use straight RO as anything but top off. RO/DI is even lower in minerals and presents an even greater risk if used for much more than top off. If your tap is very hard, RO can be used to dilute it down to reasonable mineral content levels. Once you arrive at the desired concentrations, you will need to mix the RO with tap water to keep the concentration constant in the tank. Your pH is a completely separate issue, once the water in the tank is a reasonable hardness normal approaches to reducing pH such as peat in the filter or driftwood in the tank will work to lower pH.
I do use RO on my big community tank because I keep lots of SA species in it and they tend to favor softer water than I get from tap water. I do not adjust my pH even though it runs about 7.6 from the tap and in the RO/tap mix. The fish seem to adapt very well to a constant and not too high pH like that. It keeps me from constantly having to fight the pH and causing large swings that hurt my fish.