RO/DI vs Fairfax county tap water

[mling]

After reading all about RO, I just bought a RO/DI system.  But after discussing RO with a friend,  I am now having doubts about using it for my tank.  In short my friend tells me that he does not like RO because it strips the water of everything and then you have to buy supplements to bring up the PH, etc.                

 

It is true that if the county water system is “acceptable” for aquarium use, it is better to just use tap water and use water conditioners to get rid of chlorine, versus RO ?      

 

Is there a “natural” way to raise the PH level in a reef tank ?

[tree]

The problem with just using tap water is testing it for all the various heavy metals that may be in the system in minute quantities.  These will accumulate over time in the tank.  Most of the local water supply is also very high in phosphates.  I have an RO/DI unit.  I use the Instant Ocean Salt mix and the PH has been in acceptable ranges with that mix.  I'm sure most of the mixes on the market have acceptable PH when mixed properly but others will need to comment on specific brands other than IO.

[michaelg]

You don't need to add anything back that is expensive.  Are you using pickling lime aka kalkwasser?  If so, the water will be well buffered.  A little baking soda will work as well.

Phosphates are added to help prevent pinholes from forming in copper lines.  What sort of additives did your friend say needed to be added back?  I think this is probably much much more of an issue for freshwater tanks.

[Caribbean Jake]

I live in Fairfax County - Herndon, and bought an RO/DI system.  I use instant ocean for salt and found that the PH is around 8.2.  I add pickling lime to top off water and add KENT supplemets/minerals to tanks during the week.  Have had no problems so far but I only had it for two month, making 10% water changes bi-weekly.  If you find someting or know of something that may affect the water please advise at your earliest.

Jacob