High PH in RO water

Alan

Admin
Joined
4 May 2007
Posts
5,974
Reaction score
124
Location
KZN
Guys can anybody help me here. Firstly i have really cr*py tap water. It comes out of the tap with a PH of around 8.5 and has chloramine in it. So i have to first remove the chlorine and then filter through zeolites to absorb the ammonia and then through the RO membrane. Marco and myself spent many hours getting this right. My first membrane lasted about 2 months before the ammonia destroyed it, my second one has been in for about 4yrs and only gives me a TDS reading of 5, which is still fine after all that time. I do run through DI resin after the membrane to get the TDS to 0.
My ro water still has a PH of about 8.5 after the RO/DI process which is not a problem in itself with a marine system although i used to struggle with discus.
My question is this:With that amount of buffer[what ever it is] would it impede the dissolving of Calcium Chloride to add to the system, as i know the higher the alk and PH in salt water the less CA it can hold?
 

Alan

Admin
Joined
4 May 2007
Posts
5,974
Reaction score
124
Location
KZN
No dont want to buffer RO, i use it to add calcium to the system and so dissolve a fair amount in the ro water to drip into the system over a period of time about 1 hour.
 

viper357

Admin
Joined
4 May 2007
Posts
29,910
Reaction score
1,419
I know we are straying off topic here but why do you not want to buffer your RO? Many people do, Anthony Calfo has always strongly advocated the buffering of RO water before it is added to the aquarium.
 

Alan

Admin
Joined
4 May 2007
Posts
5,974
Reaction score
124
Location
KZN
We really are getting side tracked here, i do buffer my top up water, what i need to know is will the high ph in the RO water impede its ability to hold an extremely high CA content used for raising the CA in my main system.
 
Joined
8 May 2007
Posts
2,420
Reaction score
25
Location
Durban
We really are getting side tracked here, i do buffer my top up water, what i need to know is will the high ph in the RO water impede its ability to hold an extremely high CA content used for raising the CA in my main system.
Yes...the higher the ph the less soluble calcium (ie a shot of vinegar with your top allows you to supersaturate)....however i find it highly unlikely that ro water with 0 tds could possibly have such a high ph...something not right there
 

Alan

Admin
Joined
4 May 2007
Posts
5,974
Reaction score
124
Location
KZN
Yes...the higher the ph the less soluble calcium (ie a shot of vinegar with your top allows you to supersaturate)....however i find it highly unlikely that ro water with 0 tds could possibly have such a high ph...something not right there
Has always been that way, really tried to get to the bottom of it when i bred Discus, but couldn't get the answers. I really dont know what they buffer the water with. But believe me when i say TDS 0 and PH 8.5 confuses me aswell and had Marco baffeled.
 
Joined
6 May 2007
Posts
745
Reaction score
2
Location
the slums
mekaeel said:
well we havent actually taken alans age into consideration there ;)
hahaha very funny, i love the staff i reserve the right to insult them:lol:

alan said:
We really are getting side tracked here, i do buffer my top up water, what i need to know is will the high ph in the RO water impede its ability to hold an extremely high CA content used for raising the CA in my main system.
why wouldn't it?
 
Joined
6 May 2007
Posts
745
Reaction score
2
Location
the slums
yes i know but why wouldn't it in RO, do you know of any reason that it wouldn't happen in the RO as opposed to SW
 
Joined
6 May 2007
Posts
745
Reaction score
2
Location
the slums
i am assuming your are buffering your RO water with calcium?
 

Alan

Admin
Joined
4 May 2007
Posts
5,974
Reaction score
124
Location
KZN
RO normally has a slightly acidic PH of about 6.5 because of the lack of ALK, so would be able to saturate with CA. Now with the higher ALK levels can it still saturate with CA?
 

Alan

Admin
Joined
4 May 2007
Posts
5,974
Reaction score
124
Location
KZN
i am assuming your are buffering your RO water with calcium?
Phat you cant buffer with CA you can only add it to the water.
Buffer normally refers to alkalinity, which inturn buffers the Ph, hence it is termed a buffer.
 

Top