distilled water the way to go?

You can go with distilled water but a 5gallon container of RO water will be no more than $3-5 in your LFS. It would be cheaper than buying toones and toones of distilled water.

 

The biggest problem with tap water is inconsistencey, its never the same day to day or even hour to hour. Most municipalities have multiple sources be it deep wells, streams, rivers, lakes, reservoirs, impoundments, canals..whatever.
Sources change just as demands change so what you have today may be different tomorrow. Add an additional well or surface water source and treatment changes. The pH goes down so thye begin adding orthophosphates or polyphosphates to control corrosion in the distribution system. Chlorine dissipates at the ends of the distribution system so they switch to chlorine dioxide or chloramines. A storm blows through and stirs things up so they add more chemicals and coagulants/filter aids to assist with particulate removal.

Joe Contractor hits a fire hydrant down the street while he is instaling a new sewer service. Big problem. The industrial plant on the edge of town has a bad backflow preventer and gallons of process water get sucked back in to the mains. Your neighbor left his garden hose in the treewell after fertilizing his trees and that gets sucked in when the hydrant gets hit and causes a backflow. The cooling tower down at the local shopping mall sends pressurized cooling water back into the mains.

The list goes on and on and all of these things happen daily.

The point is you have zero control over tap water even if it left the treatment plant in pristine condition. You might test for nitrates 10 minutes from now and they are low but what about the benzene from the industrial plant or the leaking gas station tank on that vacant property? Or the phosphates they added this morning when the pH dropped?

With RO and especially RO/DI you get consistency, even moreso if you own and maintain the RO/DI system yourself. I would never ever, did I say never, use tap water in a reef system no matter where I am located or what the source. You get too much invested and we as reef hobbyists should be serious about the inhabitants we are keeping. If I did not think I could keep a anemone, coral or fish for its entire lifespan I would not be in this hobby. I for one take it seriously so choose to provide the best care I possibly can.

 

See what I mean? As if I don't take it seriously because I used tap water for a year. :

AZ is right, of course, about not having control with tap. But I'm also right that there are zillions of folks who have successful long term setups using tap.

Don't get me wrong, I'll advise you to use RO/DI - from the start ideally. But I'm not going to act like $150 is cheap (it is to me, but I wouldn't ever assume it's a drop in the bucket for everyone) nor that it's impossible, irresponsible, or a lack of seriousness if you use tap.

 

It really doesn't make sense to not use RO/DI.

We take corals and fish out of their natural environments and stick them in a little glass box. We agonize over the best lights, reflectors and ballasts, best salt mix, best rock and substrate, even the best pumps and flow. Why not the best water? $150 for a RO/DI is much less than I spend on light bulbs every year, not to mention all the power it takes to run them. Without good water all those other things are useless.

30 years ago I used tap then switched to purchased RO water in 1990 when the City switched from deep wells to treated Colorado River water and finally bought my first RO system in 1992. Haven't looked back since.

 

Understand about the RO/DI. However, what about the initial set-up. Could you use tap water for the initial fill, and then after the addition of live rock and when the ammonia/nitrite levels are down begin to use the RO/DI?

 

I wouldn't. There are metals and things which are cumulative and will never go away. Its up to you but I even cured my initial 168 lbs of live rock I had flown in air freight from Tonga in RO/DI. Just didn't want to take the chance myself. At a nickle a gallon to make my own of a quarter a gallon to buy it it was cheap insurance.

 

well i guess thats getting put to the top of the list. i dont want to scrap the water i already have but should i test more things than i have been? ive been using my hydrometer and testing high range ph, nitrates, nitrites, and ammonia. i also started my tank with tap water and used the buffer start right.

 

never tap water. Distilled has real low PH so u have to buff. Ro/di is the way to go do not cheap out on this part..You will have an ongoing water quality issue.

 

If you plan to use your tap water to cure the rock at least check for phosphates and silicates first. As i said, I wouldn't do it but its up to you.'

You do not have to buffer distilled or RO/DI water, its basically neutral pH. There are too few ions to accurately measure the pH. Once added it adjusts itself to whatever it is added to and causes little pH change if any.

 

would i want to run my current water that i have in the tank salted and whatnot through the system? sorry if its a dumb ? but i was curious.